SM-4574G

SM-4574G
Union Switch & Signal Inc., an Ansaldo Signal company
SM 4574G
1000 Technology Drive, Pittsburgh, PA 15219 ● 645 Russell Street, Batesburg, SC 29006
PV-250
2-Element
AC Vane Relay
(100 Hz)
US&S Part No.
N322555-010
♦ Installation
♦ Operation
♦ Maintenance
Copyright © 2004
Union Switch & Signal Inc.
SM 4574G, Rev. 5
November 2004
Proprietary Notice
This document and its contents are the property of Union Switch & Signal Inc. (hereinafter
US&S). This document has been furnished to you on the following conditions: no right or
license under any patents or any other proprietary right in respect of this document or its
content is given or waived in supplying this document. This document or its content is not to
be used or treated in any manner inconsistent with the rights of US&S, or to its detriment, and
are not to be copied, reproduced, disclosed to others, or transferred without the prior written
consent of US&S.
Important Notice
US&S constantly strives to improve our products and keep our customers apprised of changes
in technology. Following the recommendations contained in the attached service manual will
provide our customers with optimum operational reliability. The data contained herein purports
solely to describe the product, and does not create any warranties.
Within the scope of the attached manual, it is impossible to take into account every eventuality
that may arise with technical equipment in service. Please consult your local US&S Account
Executive in the event of any irregularities with our product.
We expressly disclaim liability resulting from any improper handling or use of our equipment,
even if these instructions contain no specific indication in this respect. We strongly recommend
that only approved US&S spare parts be used as replacements.
SM 4574G, Rev. 5, November 2004
i
Revision History
Revision History
Rev.
Date
Nature of Revision
Original
July 1977
Initial Issue
*
December 1993
N.A.
*
November 1997
N.A.
*
March 2000
N.A.
4
October 2004
Revised Field Calibration Procedures
5
November 2004
Modified Field Calibration Test Procedure
*Revisions were not assigned numbers at the time these versions were issued.
ii
SM 4574G, Rev. 5, November 2004
Table of Contents
Table of Contents
Section 1. Introduction......................................................................................................................1-1
1.1. Description ...................................................................................................................................1-1
1.1.1. General .................................................................................................................................1-1
1.1.2. Coils......................................................................................................................................1-1
1.1.3. Contacts................................................................................................................................1-1
1.2. Specifications...............................................................................................................................1-1
1.2.1. Electrical ...............................................................................................................................1-1
1.2.2. Mechanical............................................................................................................................1-1
Section 2. Installation........................................................................................................................2-1
2.1. General ........................................................................................................................................2-1
2.1.1. Care in Handling...................................................................................................................2-1
2.2. Mounting base .............................................................................................................................2-1
2.3. Relay Indexing .............................................................................................................................2-1
2.4. Receptacle Contact Springs ........................................................................................................2-2
2.4.1. Old-Style Base Only .............................................................................................................2-2
2.4.2. Improved One-Piece Base Only...........................................................................................2-2
2.4.3. Installing Wires In Receptacle Contact Springs ...................................................................2-4
2.5. Relay Insertion .............................................................................................................................2-4
Section 3. Maintenance.....................................................................................................................3-1
3.1. Periodic Performance Test ..........................................................................................................3-1
3.1.1. Cleaning................................................................................................................................3-1
3.1.2. Service Requirements ..........................................................................................................3-1
3.2. Calibration....................................................................................................................................3-1
3.2.1. Recommended Test Equipment...........................................................................................3-1
3.2.2. Shop Calibration Test Procedure .........................................................................................3-2
3.2.3. In-Service and Field Calibration Test Procedure .................................................................3-4
3.3. Contact Resistance......................................................................................................................3-5
3.4. Shop Maintenance.......................................................................................................................3-5
3.4.1. Cleaning and Inspection .......................................................................................................3-6
3.4.2. Recommended Cleaning Materials ......................................................................................3-6
3.5.
Contact Burnishing and Cleaning Procedure .......................................................................3-6
3.5.1. Contacts that are Severely Burned ......................................................................................3-7
3.5.2. Contacts with Heavy Tarnish, Slightly Rough or Pitted Surface ..........................................3-7
3.5.3. Contacts with Surface Film or Oxidation (not Pitted) ...........................................................3-7
3.6. Check-Out Procedure (Performance Test)..................................................................................3-7
3.7. Repairs, Replacement and Adjustment of Relay Components ...................................................3-7
3.7.1. Recommended Tools and Test Equipment..........................................................................3-7
3.7.2. Vane Removal ......................................................................................................................3-8
3.7.3. Vane Installation ...................................................................................................................3-9
3.7.4. Contact Block Replacement and Adjustment.....................................................................3-11
3.7.5. Contact And Counterweight Adjustment Procedures.........................................................3-12
Section 4. Parts List ..........................................................................................................................4-1
4.1.
4.2.
4.3.
Main Assembly N322555-010 (Figure 4-1) .................................................................................4-1
Contact Block Assemblies N376449, N376450 (Figure 4-5).......................................................4-7
Relay Mounting Base Assembly N438689-003 (Figure 4-6).......................................................4-8
Section 5. Technical Support...........................................................................................................5-1
SM 4574G, Rev. 5, November 2004
iii
Table of Contents
List of Figures
Figure 2-1
Figure 2-2
Figure 3-1
Figure 3-2
Figure 3-3
Figure 3-4
Figure 3-5
Figure 3-6
Figure 4-1
Figure 4-2
Figure 4-3
Figure 4-4
Figure 4-5
Figure 4-6
-
Typical Plug-In Relay and Mounting Base ...........................................................................2-3
Receptacle Contact Springs Installed ..................................................................................2-3
AC Vane Relay Test Circuit..................................................................................................3-3
Adjustment of Heel Spring Clips.........................................................................................3-10
Method of Closing in the Lower Heel Spring Clips.............................................................3-11
Application of Bending Tools ..............................................................................................3-11
Table Torque Arm...............................................................................................................3-14
Inspecting Loose Counterweights and Loose Trunnion Screw Locknuts ..........................3-16
PV-250 Relay N322555-010 Top Assembly (Sheet 1 of 4) .................................................4-3
PV-250 Relay N322555-010 Top Assembly (Sheet 2 of 4) .................................................4-4
PV-250 Relay N322555-010 Top Assembly (Sheet 3 of 4) .................................................4-5
PV-250 Relay N322555-010 Top Assembly (Sheet 4 of 4) .................................................4-6
Contact Block Assemblies....................................................................................................4-7
Mounting Base Assembly .....................................................................................................4-8
List of Tables
Table 2-1
Table 3-1
Table 3-2
Table 3-3
Table 3-4
Table 4-1
Table 4-2
Table 4-3
iv
-
Crimping Tools.......................................................................................................................2-4
100-HZ Test Operating Values..............................................................................................3-4
Operating Values at Ideal Phase Relations...........................................................................3-4
In-Service and Field Calibration Operating Values ...............................................................3-5
Contact Resistances..............................................................................................................3-5
Main Assembly Parts Listing .................................................................................................4-1
Contact Block Arrangement...................................................................................................4-7
Contact Block Assembly Parts List........................................................................................4-7
SM 4574G, Rev. 5, November 2004
Introduction
Section 1. Introduction
This manual covers the PV-250 Plug-In AC Vane Relay used for track circuit applications. Since the
relay is a two-element AC vane type, it must be provided with the appropriate equipment to provide
the adequate phase displacement between the local and control (track windings). The earlier and later
design relays have the same operating characteristics and fit into the same mounting base. The design
of the PV-250 Relay conforms to all applicable AAR Specifications.
1.1. Description
1.1.1.
General
The relay is factory calibrated to operate across a wide environmental range. All moving parts are
enclosed in a sturdy, transparent, dust and moisture-resistant cover. To ensure the relay is inserted in
its proper mounting base, all relays have indexing pins. Relays lock securely in the plug-in position.
1.1.2.
Coils
This relay uses a double-wound coil that may be used in series or parallel for the control element and a
local element that presents the impedance to meet the specifications of Table 3-1.
1.1.3.
Contacts
Contacts of the PV-250 relay are standard low-voltage silver-to-silver impregnated carbon front and
silver-to-silver back. See Figure 4-5 for illustrations of the contact block assembly.
1.2. Specifications
This manual provides operating values and the parts list specific to PV-250 Track Relay N322555-010.
This relay has the following general specifications:
115V Local, 48/48 Turn Track Coil
6F-4B Contacts
Local 0.165 amp at 115V
The following subsections provide the electrical and mechanical specifications of the PV-250 relays
covered in this manual.
1.2.1.
Electrical
Relay electrical specifications are tabulated in Tables 3-1, 3-2, and 3-3.
1.2.2.
Mechanical
Dimensions:
Height
Width
Depth
SM 4574G, Rev. 5, November 2004
7-1/16" (17.93 cm)
4-15/16” (12.54 cm)
8-3/8 (2½ cm)
1-1
Introduction
Temperature:
-40°F (-40° C) to +185°F (85°C)
Indexing:
Determined by relay part number (see Section 2.3)
Weight:
8.0 lbs. (3.63 kg)
Mounting Base: N376442 (Old-Style) - 37 oz.
N438689-003 (New-Style) - 18 oz.
Mounting Base Dimensions: Height 7-15/16” (20.1 cm)
Width
4-15/16” (12.54 cm)
Depth
2-7/16” (6.19 cm) - (Old-Style Base)
Depth
1-25/32” (4.5 cm) -(New-Style Base)
1-2
SM 4574G, Rev. 5, November 2004
Installation
Section 2. Installation
2.1. General
Relays plug directly into a mounting base that is secured to a rack. The only installation instructions
required are for the mounting base.
2.1.1.
Care in Handling
It is very important that these vane relays be handled carefully so that undue stresses are not applied to
the vane structure, which might throw the vane out of adjustment. A piece of twine, which firmly holds
the vane, is applied to the relay when it leaves the factory, via a tapped hole in the rear of the relay.
The twine must be removed when the relay is placed in service. A plug screw 8-32 x 1/4 (included)
should be installed in this hole (Reference Figure 4-1, Item 13).
2.2. Mounting base
Secure the mounting base directly to the rack using the hardware furnished. All wiring terminates at
the rear of the mounting base to solderless terminals (contact receptacles). Mounting base details are
shown in the Figure 4-6.
2.3. Relay Indexing
Relays are factory equipped with indexing pins to prevent insertion of an incorrect relay into a
mounting base. Each relay is accompanied by an indexing plate that is applied to the mounting base at
the time of initial installation. A typical plug-in relay with indexing pins and base with corresponding
indexing plate is shown in Figure 2-1.
The following data defines the indexing that has been established for relays covered by this manual.
a.
The index code always consists of four figures (such as 5501, 5502, or 5510) and is used
for both the relay and the indexing plate on the mounting base.
b.
The index code for each relay can be determined from the relay part number and its suffix
which is marked on the name plate attached to the front of the relay. The first two digits of
the index code are the last two digits of the part number, and the second two digits of the
index code are the last two digits of the suffix. The index number thus obtained should
agree with the placement of the indexing pins in the numbered vertical rows on the back of
the relay starting with the top pin and reading down.
c.
The index code for each mounting base is determined by the placement of the holes in the
numbered vertical rows of the large white nylon indexing plate that is affixed to the front of
the mounting base. This indexing plate should not be removed from the mounting base
unless it is damaged or the indexing is to be purposely changed to accommodate a relay of a
different part number.
SM 4574G, Rev. 5, November 2004
2-1
Installation
WARNING
Never drill new holes in a base indexing plate that will permit
application of relays with different part numbers. Never change
indexing pins on the back of a relay, unless it is being
converted to a new part number. Otherwise, a hazard will be
created which may compromise safety circuit functions.
2.4. Receptacle Contact Springs
2.4.1.
Old-Style Base Only
The N376442 mounting base will normally be equipped with the required quantity of J680165
solderless receptacle contact springs, and will accommodate one or two #14 or #16 wires. It can,
however, be equipped with receptacle contact springs for one or two #10 or #12 wires (J680181), or
for one or two #18 or #20 wires (J680179). Make certain the type of solderless receptacle contact
springs that accompany the mounting base before proceeding with their installation.
2.4.2.
Improved One-Piece Base Only
The new one-piece mounting base (N438689-003) with hardware includes a full complement of
receptacle contact springs (M451142-2702) to accommodate one or two #14 - #16 wires, mounting
fasteners, and tags. It can, however, be equipped with receptacle contact springs for one or two #10 #12 wires (M451142-2703), or for one or two #18 - #20 (M451142-2701). Make certain of the type of
solderless receptacle contact springs that accompany the mounting base before proceeding with their
installation.
Each solderless receptacle contact springs should be inspected for physical damage before proceeding
with installation.
The following is recommended when installing solderless receptacle contact springs after crimping
wires:
2-2
a.
Receptacle contact springs must be inserted into the base with the lock side down or lanced
tab up (refer to Figure 2-2).
b.
Make certain the lanced tab is slightly compressed as the receptacle contact spring is
inserted along the top of the cavity. The lanced tab could have been bent during handling
and, if so, would not provide the required contact pressure after the relay is inserted. If the
lanced tab does not touch, pull it up slightly using fingers or a suitable tool.
c.
After insertion, pull firmly on the wire to make certain the receptacle contact spring is
locked in the cavity.
SM 4574G, Rev. 5, November 2004
Installation
Figure 2-1 - Typical Plug-In Relay and Mounting Base
Figure 2-2 - Receptacle Contact Springs Installed
SM 4574G, Rev. 5, November 2004
2-3
Installation
2.4.3.
Installing Wires In Receptacle Contact Springs
Use the following procedure to ensure a good electrical and mechanical connection between the
conductor wire and the receptacle contact spring. Table 2-1 identifies the correct crimping tool to be
used when installing wires in a receptacle contact spring.
1. Strip 3/16 in. (0.187 in. or 0.47 cm.) of insulation from the end of the wire.
2. Place the receptacle contact spring into the jaws of the proper crimping tool. When using only
one terminal, of any wire size, use the shortest terminal.
3. Partially close the crimping tool jaws against the receptacle contact spring to hold it in place.
(Do not crush the receptacle contact spring barrel at this time.)
4. Insert the stripped end of wire all the way into the receptacle contact spring barrel. Squeeze the
tool handles until crimping is completed and the jaws release. When using both terminals, it is
more convenient to attach the first wire to the longest terminal.
5. Remove the crimped receptacle contact spring from the tool and inspect the connection. Make
certain that the wire is flush with the crimped barrel and that there are no loose strands of wire.
Table 2-1 - Crimping Tools
Crimping Tool
Wire Size
Old-Style Receptacle
Contact Spring
Improved Base Receptacle
Contact Spring
J397138
#10 / #12 AWG
J680181
M451142-2703
J397139
#14 / #16 AWG
J680165 (Standard)
M451142-2702
J397188
#18 / #20 AWG
J680179
M451142-2701
2.5. Relay Insertion
Orient the relay to the mounting base with the name plate right side up; then plug the relay into the
base. The relay should be pushed firmly against the mounting base while depressing the latch rod.
After the relay is completely seated in the base, release the latch rod and pull on the handle to ensure
that the relay has locked in place.
2-4
SM 4574G, Rev. 5, November 2004
Maintenance
Section 3. Maintenance
This section provides the necessary periodic preventive maintenance procedures that must be
performed to ensure continuous, proper, and efficient operation of the PV-250 style relays covered in
this manual. Field maintenance covers periodic inspections and performance tests.
3.1. Periodic Performance Test
3.1.1.
Cleaning
Before inspecting and testing the relay, use a soft cloth to clean the exterior to remove any dirt or dust
that may have collected. A safe cleaning solution of alcohol and water or common laundry detergent
may be used for removal of accumulated dirt, grease, etc.
3.1.2.
Service Requirements
3.1.2.1.
General
Track relays must be inspected and tested at least every two (2) years. The tests and inspections are to
include: pick-up current, drop-away current, timing of slow operating and timing relays; and visual
inspection of contacts for damage or misalignment, corrosion or other contamination of parts, loose
parts inside of the cover, broken seal, and cracked or broken cover.
Relays not passing the above stated tests and inspections must be replaced and not returned to service
until the operating characteristics and conditions are in accordance with US&S specifications.
3.1.2.2.
Testing
Calibration Table 3-1 should be used for factory/shop environment only.
Calibration Table 3-3 should be used for field testing relays. This includes initial in-service testing
prior to going into service.
Relays that do not meet test and/or calibration specifications must be removed from service for shop
repair.
3.2. Calibration
3.2.1.
Recommended Test Equipment
•
Two variable autotransformers (Variac) - 115 V @ 1.0 Amp.
•
AC Ammeter - true RMS
•
AC Voltmeter - true RMS
•
Resistor - 100 ohms, 100 watts
•
SPST switch
SM 4574G, Rev. 5, November 2004
3-1
Maintenance
3.2.2.
Shop Calibration Test Procedure
This procedure should be used when relays are tested in a controlled shop environment of temperature,
voltage and frequency. It is to be used for new relays and relays that are shopped for readjustment and
recalibration. The In-Service and Field Calibration Test Procedure, Section 3.2.3, must be used
otherwise.
Note
When performing calibration, set local voltage as specified to within ± 1%. When
checking relay calibration, current readings are to be used. The voltage range shown in
the table is for REFERENCE ONLY. If the current and the voltage are measured
simultaneously it is possible for one of the readings to be out of the acceptable range. If
this is the case, as long as the current reading is within the specified range the relay is
acceptable.
Connect the circuit shown in Figure 3-1, with the control windings in parallel.
1. Set switch S1 to its OFF position.
2. Connect the circuit to a 115VAC, 100 Hz, isolated line.
3. Set Variac T1 to its minimum output setting.
4. Set switch S1 to its ON position.
5. Adjust Variac T2 to obtain 115 VAC ±1% across Variac T1 as read by voltmeter V2.
This voltage must be maintained throughout this test.
6. Slowly adjust Variac T1 to increase its output until the front contacts of the relay being
calibrated just close. Record the value indicated on ammeter A; this is the pick-up
current value and should be within the pick-up current range specified in Table 3-1.
Pick-up (PU) Current Value
__________________
7. Again slowly increase the output of Variac T1 until the vane in the relay just touches
the top roller. Record the value indicated on ammeter A; this is the full stroke current
value and should be within the full-stroke current range specified in Table 3-1.
Full Stroke (FS) Current Value __________________
8. Slowly adjust Variac (T1) to decrease the output until all front contacts of the relay
open. Record the ammeter A reading; this is the drop-away (DA) current value. It
should not be less than the percentage (specified in Table 3-1) of the actual pick-up
current value measured in Step 6.
Drop Away (DA) Current Value
__________
The DA current value must not be less than (0.8 x PU current value).
3-2
SM 4574G, Rev. 5, November 2004
Maintenance
115 VAC, 100 Hz
(ISOLATED LINE)
T2
* 115 VAC + 1%
CAN BE MAINTAINED
WITH VARIAC T2
ON
OFF
115 VAC + 1% *
S1
V2
MIN.
MAX.
T1
R
100
100W
V1
A
FOR
REFERENCE
ONLY
(1F)
C1
C1+
(1A)
(2F)
C2-
C2
(2A)
(8A)
L-
L+ (7A)
RELAY UNDER TEST
(New Style Base Contacts Shown with Parentheses)
Old Style Base Contacts Shown without Parentheses
Figure 3-1 - AC Vane Relay Test Circuit
SM 4574G, Rev. 5, November 2004
3-3
Maintenance
Table 3-1 - 100-HZ Test Operating Values
Torque
(Inch Grains)
275
*
Pick-Up (PU)
Volts
Amps*
(for ref. only)
0.31 - 0.39
0.54 - 0.66
Full Stroke (FS)
Volts
(for ref. only)
Amps*
0.46 - 0.53
Min. Drop-Away %
of Actual PU
0.85 0.95
80
The digital ammeter should be set to display only two-decimal place accuracy. Any additional decimal places are
insignificant to the relay calibration and should be ignored. Track coils connected in multiple. The values given
in Table 3-1 are nominally 17% higher than values at ideal phase relations shown in Table 3-2 and apply to tests
using single-phase supply with resistance in series with the track winding.
Table 3-2 - Operating Values at Ideal Phase Relations
(Values shown are for technical use and for calibration tag information only.
Not to be used for normal calibration purposes)
Pick-Up (PU)
Volts
Amps
0.3
0.51
Full Stroke (FS)
Volts
Amps
0.43
Min. Drop-Away %
of Actual PU
0.77
80
With ideal phase relations, the track volts lead the line volt 90° and the track amperes lead the line volts
24°.
3.2.3.
In-Service and Field Calibration Test Procedure
The following procedure should be used anytime a relay is tested in the field. For example: when a
relay has been in operation for any period of time or during initial in-service testing prior to going into
service, or when the environment of temperature, voltage and frequency is not controlled, as in a shop
or factory environment.
Connect the circuit shown in Figure 3-1, with the control windings in parallel.
1. Set switch S1 to its OFF position.
2. Connect the circuit to a 115VAC, 100 Hz, isolated line.
3. Set Variac T1 to its minimum output setting.
4. Set switch S1 to its ON position.
5. Adjust Variac T2 to obtain 115 VAC ±1% across Variac T1 as read by voltmeter V2.
This voltage must be maintained throughout this test.
6. Slowly adjust Variac T1 to increase its output until the front contacts of the relay being
calibrated just close. Record the value indicated on ammeter A; this is the pick-up
current value and should be within the pick-up current range specified in Table 3-3.
Pick-up (PU) Current Value
3-4
__________________
SM 4574G, Rev. 5, November 2004
Maintenance
7. Again slowly increase the output of Variac T1 until the vane in the relay just touches
the top roller. Record the value indicated on the ammeter; this is the full stroke current
value and should be within the full-stroke current range specified in Table 3-3.
Full Stroke (FS) Current Value __________________
8. Slowly adjust Variac (T1) to decrease the output until all front contacts of the relay
open. Record the ammeter reading; this is the minimum current drop-away value. It
should not be less than the percentage (specified in Figure 3-3) of the actual pick-up
current value measured in Step 6.
Drop Away (DA) Current Value _________________
DA current vale must not be less than (0.8 x PU current value).
Table 3-3 - In-Service and Field Calibration Operating Values
Current
(Amps)
Acceptance Criteria*
Pick Up (PU)
0.54 Min. – 0.95 Max.
Front contacts should be “closed”
Full Stroke(FS) Max.
0.95 Max.
Vane should touch upper roller
Drop Away (DA)
0.43 Min.
Front contacts should be “open”
*If relays don’t meet the Acceptance Criteria they must be shopped for readjustment and recalibration.
3.3. Contact Resistance
Resistance of front contacts should be measured with the armature in its full-stroke position, and
resistance of back contacts should be measured with the armature fully released. Cleaned contact
resistance should not exceed the values shown in Table 3-4.
Table 3-4 - Contact Resistances
Type of Contacts
Silver-to-Silver Impregnated Carbon
Silver-to-Silver
Front
Contacts
(ohms)
Back
Contact
(ohms)
0. 09
----
----
0. 03
Contact surfaces should not be disturbed unless there is evidence of severe pitting from excessive
loading or an accidental short through the contacts. When contacts must be dressed and cleaned refer
to Section 3.1.
3.4. Shop Maintenance
This section provides the information necessary to perform shop level repairs of the PV-250 style
relays covered in this manual. In general, relays arriving at the shop for repair have been checked in
the field and have been found to perform unacceptably or have been physically damaged.
SM 4574G, Rev. 5, November 2004
3-5
Maintenance
3.4.1.
Cleaning and Inspection
Before inspecting the relay and initiating repairs, use a soft cloth to clean the exterior carefully to
remove any dirt or dust that may have collected. A safe cleaning solution of alcohol and water may be
used for removal of accumulated dirt, grease, etc.
Inspect the relay exterior for signs of physical damage, such as cracked or broken cover, cracked or
damaged housing, and damaged and/or missing contact block terminals and indexing pins. If severe
external damage is found, a careful inspection of the interior components should be made for obvious
physical damage. Proceed with relay contact cleaning, using the following recommended cleaning
materials.
3.4.2.
Recommended Cleaning Materials
The following tools are recommended for cleaning the relay:
US&S
Part Number
Tool
Burnishing Tool, P.K. Neuses Co. No. 3-316
J397187
Burnishing Tool, P.K. Neuses Co., No. N318 (Heavy Duty)
J397187-001
Paper Cleaning Kit (50 strips, 5/8” x 7 1/2”)
J793094
Paper Strip, strips cut from 67# white Springhill Vellum Bristol Paper
J793094
Individual items from the kit are also available by ordering the part number designated beside each
item.
Also recommended (commercially available)
Emory Paper (Wet or Dry): 600 Grit, cut in strips
Alcohol #1 Solvent (Ethyl Alcohol Proprietary 190 or Equivalent)
Note
In the final cleaning procedures outlined in the following sections, it is recommended that all silver
contacts be cleaned first, followed by all silver impregnated carbon contacts. This will to prevent
contamination of the silver tips with residue that adheres to the cleaning tool after cleaning the silver
impregnated carbon contacts.
When using the paper strip, clean the back contacts first and the front contacts last. Discard the paper
strips when dirty.
3.5.
Contact Burnishing and Cleaning Procedure
Since the contacts are the major wearing parts in this relay, in most cases the relay can be restored to
proper operation by dressing and readjusting them.
3-6
SM 4574G, Rev. 5, November 2004
Maintenance
3.5.1.
Contacts that are Severely Burned
a.
Using a 600-grit emery paper strip, folded with grit side out so that both contacts can be
burnished simultaneously, stroke the contacts in the direction of the contact wipe.
b.
Using the burnishing tool, stroke the contacts several times in the direction of the contact
wipe.
c.
Place the paper strip between the open contacts, then close the contacts and withdraw the
paper strip.
d.
Repeat Step “c” several times, if necessary.
e.
Using the alcohol spray, give the contacts a degreasing/wash.
f.
Place the paper strip between the open contacts, then close the contacts and withdraw the
paper strip.
g.
Repeat Step “f” several times, if necessary.
3.5.2.
Contacts with Heavy Tarnish, Slightly Rough or Pitted Surface
a. Conduct Steps “b” through “g” of the above procedure.
3.5.3.
Contacts with Surface Film or Oxidation (not Pitted)
a. Conduct Steps “f” and “g” of the above procedure.
3.6. Check-Out Procedure (Performance Test)
After the contacts have been burnished and cleaned, and if no additional work is needed the following
must be done:
1. Conduct the contact adjustment procedure in Section 3.7.5.2.
2. Conduct the electrical calibration procedure in Section 3.
The above steps must be done before returning the relay to service.
3.7. Repairs, Replacement and Adjustment of Relay Components
3.7.1.
Recommended Tools and Test Equipment
Screw Driver - Torque Measuring
Thickness Gauges - 0.001 - 0.058 in.
SM 4574G, Rev. 5, November 2004
3-7
Maintenance
3.7.2.
Vane Removal
Dismantle the relay only to the degree necessary to complete repairs. Refer to the Appendix A for part
information and location of parts. In general, to dismantle the plug-in relay, proceed with the following
sequence:
a. Remove seal and seal wire
b. Carefully remove plastic cover
c. Remove the vane assembly as required
d. Remove contact block as required
e. Remove Local/Control Field as required
3.7.2.1.
Vane Removal Procedure
a. Remove the bottom roller stop by bending the left bracket, looking at the relay, about 1/4” to
the left. Do not move the brackets forward or to the rear.
b. Disengage the contact operating arms from the clips on the heel contact springs by pulling the
arms forward at the lower ends.
c. Remove all bushings and pins from the contact operating arms.
d. Remove the counterweight nuts from the front end of the vane assembly and loosen the lock
nuts from the trunnion screws.
e. Place the relay on its mounting surface with the contacts forward.
f. Insert a piece of paper in the air gap on each side of the vane to protect it from being scratched
by the pole pieces during removal.
g. Turn the trunnion screws out until they are flush with the inside surface of the support casting.
h. Remove the trunnion lock nuts from the shaft.
i. Lower the shaft until the vane edge rests on the machined slot of the contact blocks.
j. Move the vane shaft forward and up until the upper back contact heel springs (No. 4 and 5 can
be pushed in back of the shaft). Note: The operating arms must be held clear of the heel
springs.
k. Rotate the counterweight stud toward the contacts and slide the hub out between the heel
springs and the roller stop guide. Note: This will require a slight deflection of the upper front
heel contact springs. The crank pins and contact operating arms can then be removed after the
vane is out of the relay.
The above procedure applies to a six-front, four-back relay with a machined slot in the contact blocks
to accept the vane and machined slots in the relay frame. This allows the trunnion screws to be backed
out flush with the inside surface of the support casting.
3-8
SM 4574G, Rev. 5, November 2004
Maintenance
Relays with fewer contacts and having machined slots, such as the two-front, two-back relay, follow
the same general procedure except that removal of the vane past the contacts is more easily
accomplished.
Note
A limited number of early production relays did not have the machined slots in the contact
blocks and the relay frame. Also, a limited number had the machined slot in the contact block
but not in the relay frame. In order to remove the vane from a relay with no machined slots, it
is necessary to remove the contact blocks entirely and lower the support casting sufficiently to
allow the trunnion screws to clear the relay frame. Relays with only the machined slot in the
contact blocks require that the support casting be lowered sufficiently to allow removal of the
trunnion screws. The support casting should then be put back in place and the vane removed
as formerly described in detail.
If it is necessary to remove the fields from the supporting bracket, care must be used in
reassembling to make sure that the air gap is between 0.080 inch and 0.085 inch.
3.7.3.
Vane Installation
Vane installation is accomplished generally in the reverse order of the removal procedure. Do not
over-tighten or force parts. The following subsections provide additional instructions to be followed.
Upon completion of reassembly and readjustment electrically calibrate the relay as described in
Section 3.2.
3.7.3.1.
Vane Installation Procedure
1. Check the pivots and trunnion bearings for excessive wear. Clean them with a dry, lintless
cloth before installing the vane.
2. Assemble the contact operating arms and crank pins on the vane cranks first.
3. Insert the vane. At least one of the trunnion screw lock nuts should be started on the trunnion
screws in advance, but it may be found necessary to slide the other nut on one end of the vane
shaft in order to bring it into position.
4. Tighten the trunnion screws carefully so as not to damage the pivots. These screws should be
adjusted to center the vane in the air gap and to provide 0.010” to 0.016” endplay of the vane
shaft. With the endplay taken up on each side, rotate the vane and inspect to ensure that the
minimum clearance from the vane to the pole face is 0.012”. If the vane clearance is less
than 0.012” reset the endplay and recheck the clearance. After the endplay has been set
tighten the trunnion lock nuts.
5. Adjust the stroke of the vane by adjusting the roller stop brackets to permit maximum travel
of the vane. In either extreme position of the vane, as permitted by the roller stops (rollers at
the top of the slot), the buffer clips on the vane should be 3/32 inch from the cores. This
adjustment allows maximum travel of the vane and prevents the buffer clips from becoming
wedged in the air gap.
SM 4574G, Rev. 5, November 2004
3-9
Maintenance
6. Check that the heads of the crank pins have at least 1/16” clearance from the lock nuts on the
trunnion screws when the pin and vane shaft are shifted to make this clearance minimum.
Check that the crank pins are securely locked at the split ends so that this clearance cannot be
reduced.
7. Check to ensure that the operating arms swing freely without any tendency to bind.
3.7.3.2.
Operating Arms Installation Procedure
1. Check Operating Arms to see that warpage does not exceed 0.010". Discard any that are
warped greater than 0.010".
2. Assemble the operating pins and bushings and push them into the clips on the heel contact
springs. The lower clips should have moderate tension to hold the bushings in place once they
are assembled.
3. Adjust the heel spring clips with the specially designed pliers M263832 as shown in Figure 3-2
and Figure 3-3. All bushings should be positioned with the flanges against the heel clips.
4. Bend the heel spring supporting members sideways using alignment tool J397164-0020, as
shown in Figure 3-4, so that there is clearance of not less than 0.005” nor more than 0.055” to
each contact bushing. Note: Take up the side play of the operating arm in either direction
before they are bent. The jaw of the tool should be applied over the portion of the supporting
member where it is riveted to the contact spring.
5. Check to be sure that all split pins in the operating arm connections are properly spread.
Figure 3-2 - Adjustment of Heel Spring Clips
3-10
SM 4574G, Rev. 5, November 2004
Maintenance
Figure 3-3 - Method of Closing in the Lower Heel Spring Clips
Figure 3-4 - Application of Bending Tools
3.7.4.
Contact Block Replacement and Adjustment
3.7.4.1.
Contact Block Replacement Procedure
1. Remove the old block.
2. Use a small punch to remove the small dowel pins.
3. Attach the new block with the four screws.
SM 4574G, Rev. 5, November 2004
3-11
Maintenance
4. Drill a (#42 drill, 0.0935” Diameter) through the dowel pin holes into the contact block for
a total depth of 9/16” + 1/32 - 0.
Note
Replacement contact blocks MUST be of the same general design.
5. Install the dowel pins by carefully tapping them in until they are flush with the aluminum
surface. If it is necessary to install a used contact block from another relay, remove only
one of the dowel pins from the aluminum frame. Carefully press the block on the remaining
pin and fasten in place with the screws. One dowel pin will adequately hold the block in
place. Install the contact block mounting screws and torque them to 10 ± 2 inch pounds.
6. Do not over-tighten or force parts during reassembly.
3.7.5.
Contact And Counterweight Adjustment Procedures
All adjustments of contacts should be made by bending the brass support member with the bending
tool applied between the rivets that fasten the contact spring to it. Because of the effect of the weight
of the contact tips, all checks of contact adjustment should be made with the relay in the normal
upright position.
3.7.5.1.
Recommended Tools
Gap Gauge - 0.001" to 0.060"
Gram Scale - 0 to 30 grams
Pliers (Heel Clip) - M263832
Bending Tool - J397164-0020
Bending Tool - N451151-2401
Adjustable Torque Arm - N171156
3.7.5.2.
Initial Contact Adjustment Procedure
a. Front and Back Contacts
1. Adjust all front and back contact springs to have an initial pressure of 20 grams (10
grams each tip). This may be reduced to 12 grams, corresponding to 6 grams at each tip,
as required to meet calibration values.
2. Apply a gram scale at the center of the contact tip, on the back contact springs, to just
barely move the flexible bronze spring away from the curved stop member. The stop
member should be bent if necessary, not the spring, in obtaining this adjustment. In
order to make this check on the front contact springs, using the gram scale, the spring
assembly will have to be checked in the inverted position and the pressure should be 18
3-12
SM 4574G, Rev. 5, November 2004
Maintenance
grams (9 grams each tip), to compensate for the weight of-the contact tip. The contact
buttons of the bifurcated springs should close at the same instant.
b. Heel Contacts
1. The design of heel contact provides a flexible hinge arrangement with a rigid assembly
on the outer part of the member. The thin center spring should be straight and the
projection on the upper and lower pressure plates should both bear against the thin
center spring. This heel spring assembly should deflect through its full motion - with
very slight pressure from the operating arm. The heel spring has to be handled carefully
in order not to distort the thin center member.
2. Adjust the heel springs so that when the relay is held with the base horizontal and the
contact springs pointing downward, the heel spring will take a free position when not
connected to the operating arm without appreciable bias either toward the front or back
contacts.
3.7.5.3.
Final Contact Adjustment Procedure
The normal contact adjustment provides 0.031" compression of the front contacts with the vane just
touching the upper roller stop, 0.025" compression of the back contacts when the vane just touches the
lower roller stop, and 0.025" opening of the back contacts with the fronts just barely closed. These
adjustments can be obtained by using the proper section of three-way bending tool N451151-2401
applied as shown in Figure 3-5.
1. Align the front and back contact springs with their associated heel springs using alignment tool
J397164-0020 as explained for the heel contact springs.
2. Adjust the front contacts to have 0.055" opening with the vane resting against the lower roller
stop.
3. Adjust the back contacts so that they have 0.025" opening with the fronts just barely closed.
4. Move the vane up against the upper roller stop, the opening of the back contacts should be
approximately 0.055". As a further check, each front contact spring should have approximately
0.010” opening from its stop spring.
5. Move the vane to touch the lower roller stop. Each back contact spring should have
approximately 0.010” opening from its stop spring.
6. Check electrical calibration per Section 3.3.
3.7.5.4.
Counterweight Adjustment Procedure
The values for vane torque given in Table 3-1 refer to the counterweight torque needed to just balance
the vane so that the front contacts just barely close when the relay is in the normal mounted position
without current in the windings and the case is tapped lightly. Unless the adjustment of the
counterweight nut or the heel contact springs has been changed, or the operating values are not met,
SM 4574G, Rev. 5, November 2004
3-13
Maintenance
this check will not ordinarily have to be made. In general, it is permissible for the torque to be more
than the value shown, provided the operating values are correct.
1. Attach the “adjustable torque arm” Figure 3-5 onto the vane shaft of the relay with the opening
of the slot at the bottom, as shown.
2. Hold the “adjustable torque arm” in place by turning the arm, which is threaded on the end,
until it is tight against the vane shaft.
3. Move the small weight that is attached to the “adjustable torque arm” to give the desired
counterweight as specified in Table 3-1.
4. Adjust the counterweight nuts on the relay so that the front contacts will just make, with the
“adjustable torque arm” in a horizontal position. This can be easily determined by tapping the
relay case lightly.
VANE SHAFT
Figure 3-5 - Table Torque Arm
The notches on the arm are spaced to provide the counterweights ordinarily used. With the
small weight in the notch nearest the vane shaft a counterweight of 100 inch-grains is
indicated; in the second notch 125 inch-grains; in further 25 inch-grain steps to 300 inch-grains
and 50 inch-grain steps to 600 inch-grains, except an extra notch at 375 inch-grains.
5. Adjust the counterweight nuts on the vane so that a torque as specified in Table 3-1 is required
to just close the front contacts. This torque should be measured with the relay in its normal
operating position and with all operating arms connected to the heel contacts, using an
adjustable torque arm. At least 1/16" clearance should exist between the end of the
counterweight screw and the main support casting.
6. Lock the counterweight lock nut securely and spread the end of the screw slightly to prevent
the nuts backing off.
3-14
SM 4574G, Rev. 5, November 2004
Maintenance
3.7.5.5.
Inspection for Loose Counterweights and Loose Trunnion Screw Locknuts
WARNING
The following procedure involves the opening of a vital relay.
Individuals qualified to work on vital relays must perform this
procedure.
1. Remove the bottom cover from the relay. This exposes the contact assembly. Exercise
extreme caution not to disturb the adjustment of the contacts.
2. Remove nameplate to gain access to the counterweight assembly on the vane crank.
3. Rotate the vane so that the counterweight assembly is visible. This will reveal one or more
counterweights, with or without a locknut, on the counterweight screw.
4. As shown in the figure below, check to determine if:
a. The counterweight and locknut are tight.
b. At least two threads are visible on the counterweight screw end.
c. The split screw end is slightly spread apart. Tighten any loose counterweights and
locknut.
5. Conduct a visual inspection of the relay. Check for:
a.
Rubbing vane.
b.
Debris inside the relay.
c.
Obviously misaligned contacts.
d.
Check to see that the vane is approximately centered and that it has the correct amount
of end play (0.010 to 0.016 inch). Readjust if required.
e.
Check the vane for freedom of movement.
f.
Check to see that the operating arms, clips, and bushings are in the proper position and
are free to move.
g.
Using a wrench, check the trunnion locknuts for tightness. Tighten any that are loose.
6. Perform an electrical calibration test in accordance with Section 3.2.2. If the relay passes
the In-service/Field Calibration requirements apply glyptal to the exposed threads of the
counterweight screw and trunnion locknut, as shown in Figure 3-6.
7. Install gaskets and covers and seal with a new wire and lead seal.
SM 4574G, Rev. 5, November 2004
3-15
Maintenance
Figure 3-6 - Inspecting Loose Counterweights and Loose Trunnion Screw Locknuts
3-16
SM 4574G, Rev. 5, November 2004
Parts List
Section 4. Parts List
4.1. Main Assembly N322555-010 (Figure 4-1)
Table 4-1 - Main Assembly Parts Listing
Item
Description
US&S Part
No.
1
Frame
M376046
2
Rod, Latch
M375913
3
Button, Latch
J770536
4
Nut
M395496
5
Latch
M321728
6
Pin
J048716
7
Spring
M321861
8
Pin - Roll
J487087
9
Screw
J522042-001
10
Bottom Cover
J776304-0001
11
Screw, #8 - 32 x 7/16” Fil. Stl. T.P.
J522042
12
Gasket
J047081
13
Screw, #8 - 32 x ¼” Rd. Stl. T.P.
J052639
14
Handle
J561111
15
Washer, #10 Int. Tooth, Ph. Brz.
J047710
16
Screw, #10 - 32 x 3/8” Philp.
J525277
17
Seal, Vent
J790257
18
Tag, Calibration
S002036
19
---
---
20
Wire Seal
A043013
21
Seal
J079351
22
Plate, Name
M437859
23
Screw, #4-40 x 3/16” Rd. Stl.
J525024
24
Bracket, Support
M375890
25
Screw, #10 - 32 x ½” Flat Stl. T.P.
J052091
26
Field, Control
N377070
27
Field, Local
N272934
28
Vane
N380678
29
Screw, Trunnion (not shown)
N124889
30
---
---
31
Bushing
M232934
32
Bushing
M283459
33
Roller
M069693
SM 4574G, Rev. 5, November 2004
Note
*
4-1
Parts List
Item
Description
34
Bracket, Upper Roller
M397483
35
Bracket, Lower Roller
M161753
36
Plate
M090506
37
Lock, Bracket
M109074
38
Rivet
J049813
39
---
---
40
Pin
M381128
41
Washer, #8 Lock
J047714
42
Pin
M381129
43
Pin
M232031
44
Pin
M232935
45
Block, Terminal
M385775
46
Screw, #8-32 x 7/16” Rd. Hd. Stl. T.P.
J525106
47
Indexing Pin
J487090
48
---
---
49
Bag Part
N349711-5510
50
Block, Contact
N376449
51
Block, Contact
N376450
52
Screw, #8-32 x 7/8" Rd. Stl. T.P.
J052603
53
Arm, Operating
N390324
54
Counterweight
M451175-0303
55
Nut, Counterweight Lock
M029956
56
Cover, Top
N384546
57
Screw, #6-32 x 1/4” Fil. Hd.
J052485
58
Washer, #6 Lock
* Includes trunnion M124887, nut M029577.
4-2
US&S Part
No.
Note
J047713
SM 4574G, Rev. 5, November 2004
Parts List
Figure 4-1 - PV-250 Relay N322555-010 Top Assembly (Sheet 1 of 4)
SM 4574G, Rev. 5, November 2004
4-3
Parts List
Figure 4-2 - PV-250 Relay N322555-010 Top Assembly (Sheet 2 of 4)
4-4
SM 4574G, Rev. 5, November 2004
Parts List
Figure 4-3 - PV-250 Relay N322555-010 Top Assembly (Sheet 3 of 4)
SM 4574G, Rev. 5, November 2004
4-5
Parts List
Figure 4-4 - PV-250 Relay N322555-010 Top Assembly (Sheet 4 of 4)
4-6
SM 4574G, Rev. 5, November 2004
Parts List
4.2.
Contact Block Assemblies N376449, N376450 (Figure 4-5)
Table 4-2 - Contact Block Arrangement
US&S
Part
No.
6
5
4
3
2
1
Row
N376449
“G”
“B”
--
“F”
“F”
“F”
Section
View
N376450
“E”
“E”
--
“D”
“D”
“D”
←
Table 4-3 - Contact Block Assembly Parts List
Item
Description
US&S Part No.
1
---
---
2
Spring, Contact
N376006
3
Spring, Contact
N376007
4
Spring, Contact
N376002
5
---
---
6
Finger, Contact
M375981
7
Spring, Contact
N376003
Figure 4-5 - Contact Block Assemblies
SM 4574G, Rev. 5, November 2004
4-7
Parts List
4.3. Relay Mounting Base Assembly N438689-003 (Figure 4-6)
Item
Description
US&S Part No.
1
Molded Base
J780054
2
Strike, Relay
J792848
3
Nut, Speed Type
J480280
4
Spring Contact
M451142-2702
5
Tag, Relay ID
J075951
6
Screw, 1/4-20 x 1-1/4”, SST
J500136-0120
7
Washer, # 1/4 Lock, SST
J475121-0111
8
Washer, #1/4 Plate, SST
J475120-0112
9
Nut, 1/4-20 Hex, SST
J480211-0108
--
Contact Receptacle Spring -#18 - #20 Wire
M451142-2701
Contact Receptacle Spring -#14 - #16 Wire
M451142-2702
Contact Receptacle Spring -#10 - #12 Wire
M451142-2703
Figure 4-6 - Mounting Base Assembly
4-8
SM 4574G, Rev. 5, November 2004
Technical Support
Section 5. Technical Support
The Rapid Action Information Link Team (RAIL Team) is a group of experienced product and
application engineers ready to assist you to resolve any technical issues concerning this product.
Contact the RAIL Team at 1-800-652-7276 or by e-mail at railteam@switch.com.
SM 4574G, Rev. 5, November 2004
5-1
Technical Support
5-2
!UNION SWITCH & SIGNAL!~
SM 4574G, Rev. 5, November 2004
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