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I SMI No. RDSO/2016/EUSMI/0293
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Rev. 'O',Dated 29.07.2016
I Issued in 2016
Government of India - Ministry of Railways
Research,Designs& StandardsOrganization, LUCKNOW-
226011
226011
Tele/Fax: 2465754& 42226 (Rly)
e-mail: dse4cs@gmail.com
No. EL/3.1.1 0/2
Date 29.07.2016
Chief Electrical Engineer,
1. Central Railway, Mumbai, CST-400 001.
2. East Central Railway, Hazipur-844101.
3. East Coast Railway, Chandrashekharpur, Bhubaneshwar751016.
4. Eastern Railway, Fairlie Place, Calcutta-700001.
5. North Central Railway, Block-A, Subedarganj, Allahabad211033.
6. Northern Railway, Baroda House, New Delhi-110001.
7. South Central Railway, Secunderabad-500 071.
8. South East Central Railway, Bilaspur-495004.
9. South Eastern Railway, Garden Reach, Calcutta-700 043.
10. Southern Railway, Park Town, Chennai-600 003.
11. West Central Railway, Jabalpur-482001.
12.Western Railway, Churchgate, Mumbai-400 020
1.
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SPECIAL MAINTENANCE INSTRUCTION No. RDSO/2016/ELlSMI/0293 Rev. '0'
Dated: 29.07.2016
1.0 Title: Maintenance instructions for roof mounted air conditioning system
for cabs of Electric Locomotives.
2.0 Object:
Roof mounted cab AC units are being provided on the electric
locomotives. In order to have better reliability of the equipment a need for
comprehensive maintenance instruction was being felt. This SMI has been
prepared to lay down guidelines for maintenance of cab ACs for electric
locomotives.
3.0 Maintenance activities during minor schedules:-
SN
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.1.6
Activities
IT
General
Check the loco logbook and attend the defects ,f
recorded.
Run the AC unit in (Off, Auto, Manual cooling) all .y
modes. Attend to any abnormalities observed.
Clean dust from control panel by compressed air
or vacuum cleaner and tighten the cable
terminals.
Remove return air filters by opening the grill.
Clean these filters with water/vacuum cleaner or
compressed air.
Check for damaqed/iointed cable.
Ensure top cover of AC unit proper locking and
gasket. Replace gasket if damaged.
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Page 2 of 6
SN
3.1.7
I
SMI No. RDSO/2016/EUSMI/0293
Activities
Run the AC unit for half an hour and record the
current drawn by various equipments with the help
of clamp tester.
Nominal Current
Equipment
4.5 - 6.0 Amp.
AC unit in cooling mode
2.0 - 3.0 Amp.
AC unit in heating mode
2.0 - 4.0 Amp.
Compressor Motor
0.6 - 0.8 Amp.
Condenser Motor
0.4 - 0.6 Amp.
Blower Motor
Switch 'ON' the AC unit (Blower motor ON,
Condenser motor ON, Compressor ON) and
rotary switch set the manual cooling mode then
check the time delay relay for its operation.
Compressor must start within 180+15 Sec.
3.1.9 Run the AC unit in auto mode and check the cut-in
and cut-out of thermostat. If thermostat is not
working properly check the following:
• Clean the cooling sensor probe and heater
sensor probe.
• Ensure Thermostat connector is properly
tightened.
3.1.10 Ensure that there is no leakage of condensate
water from trough to driver cab. Rectify any
leakage.
Control Panel
3.2
3.2.1 Check intactness of control panel connectors.
3.2.2 Check working of rotary switch by rotating forward
and backward. Replace, if found loose, damaged
and jammed.
3.2.3 Check the working of all LED's indications for
proper function:
i) Rotate the rotary switch in manual cooling mode
position and check the status of LED (Main -ON,
BLR-ON, CaMP-ON, COOL-ON).
ii) Rotate the rotary switch in Auto mode position
and check the status of LED (Main- ON, BLR-ON,
CaMP-ON, COOL-ON in summer) and (Main ON, BLR-ON, HTR-ON in winter).
In case LEOs do not light up, check 110 V AC
control supply. Rectify any abnormalities.
3.2.4 Check and clean step-down transformer (Control
Transformer) 415V/11 OV and its connections.
Condenser motor and blower motor
3.3
3.3.1 Clean the body of condenser motor and blower
motor by compressed air.
3.3.2 Check condenser motor visually for crack on
blade or body.
3.3.3 Check and ensure mounting fasteners are
properly tightened.
3.3.4 Check connection at terminal boxes of motor for
proper tightens & cables are terminated with IUQs.
3.1.8
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Rev. 'O',Dated29 07 2016
IT
Issued in 2016
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I Page 3 0[6
I SMI No. RDSO/2016/EUSMI/0293
Rev. 'O',Dated29.07.2016
I Issued in 2016
SN
Activities
IT IA IB IC
3.3.5 Check insulation resistance of motors by 500 V DC
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megger from the control panel. Attend the motors if
insulation resistance is less than 2 MO.
3.3.6 Check motors for any abnormal sound while running.
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Compressor
3.4.1 Check and ensure mounting fasteners are properly
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tightened.
3.4.2 Check electrical terminal box is properly tightened and
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cables are terminated with lugs.
3.4.3 In case of abnormal sound:
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• Check the sequence of electric connection.
• Ensure that the winding resistances of compressor
motor between UV, VW and WU phases are
balanced ± 3%.
3.5
Heater
3.5.1 Ensure proper mounting of heater without touching
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side bodies.
3.5.2 Ensure proper clamping of electric wires to heater.
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3.5.3 Remove dust accumulation on heating element gently
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by soft brush/dry air.
3.5.4 Clean thermostat temperature probe (OHP). Replace if
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cracked or broken.
3.5.5 Check heater at the beginning of winter season by
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checking current drawn at control panel by clamp
tester. (Nominal 2.0 - 3.0 Amp.)
3.6
Trough
3.6.1 Make sure condensate/rain water drains properly. This
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can be checked by opening the evaporator top and
condenser top of the system by pouring water into the
trough and clean the trough pipe by adequate size of
round brush. It should be assured that there is no
blockage in drain pipes.
3.6.2 Ensure that there is no leakage of water to cab.
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3.7
OHP (Over heat protection), HP (High pressure), LP Low _Q_ressurel
3.7.1 Check the mounting fasteners are _Qro_2_er!y_
tl9_htened.
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3.7.2 Ensure that control wires to HP/LP/OHP cut-out are
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properly clamped.
3.8
Time Delay Relay (TOR)
3.8.1 Clean the complete assembly by compressed dry air
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jet.
3.8.2 Check the condition of the TOR for physical dama_g_e.
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3.8.3 Tighten terminal & mounting screws.
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3.8.4 Replace damage thimbles/lugs.
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3.9
MCBs (Miniature circuit breaker) & MPCB (Motor protection circuit
breaker)
3.9.1 Clean the MCSs and MPCS with dry_com_Qressedair.
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3.9.2 Check the condition of MCBs and MPCB for physical
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damage.
3.9.3 Ensure that end locks are provided.
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3.4
I Page4 of6
SN
3.9.4
3.10
3.10.1
3.10.2
3.10.3
3.11
3.11.1
3.11.2
3.11.3
I
SMI No. RDSO/2016/EUSMI/0293 Rev. 'O',Dated 29.07.2016
I Issued
in 2016
Activities
IT IA IB IC
Tighten electric cable connections and DIN rail
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screws.
Contactors
Clean the contactors with dry compressed air.
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Check continuity between the incoming and outgoing
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terminals.
Ensure tightness of connection.
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Connector
Open the connectors and check for flash
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marks/damage to _gins.
Ensure that they are tightened properly.
'>/
'>/
'>/
Remove moisture b_y_
blowing air through hot air gun.
'>/
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" "
" "
" "
4.0 Maintenance activities during major schedules:SN
Activities
4.1
4.2
4.2.1
All items of IC schedule
General
Remove return air filters by opening the grill.
Clean these filters with water/vacuum cleaner or
compressed air.
Ensure proper locking of top cover of AC unit
and provision of gasket. Replace gasket if
damaged.
Condenser motor and Blower motor
Run motor on no load for 15 minutes and check
the following:
• Bearing noise- Normal noise
• Bearing temperature rise above ambient
should not more than 10°C.
• SPM (Shock pulse meter) reading - 20 dBN
max. (Green zone)
Replace bearings if defective.
"
"
Replace
Overhauling of blower and condenser fan motor:
• Measure Insulation Resistance (IR)
between motor terminals and frame
before and after overhauling. The value
should not be less than 10 MO when the
measured with 500 V megger.
• Check terminal block and connecting lead
for any physical damage or any flash
mark.
• Perform HV (Oi-electric) test on stator by
applying 1.5 kV AC apply for one minute.
The leakage current which should not
exceed 1.0 mA.
• SCT (Surge comparison test) of stator at
1 kV.
• Measure starting current of motors on no
"
"
4.2.2
4.4
4.4.1
4.4.2
AOH
"
IOH
"
PO
H
'>/
Replace
'>/
I
I Page5 of6
4.5
4.5.1
4.5.2
4.6
4.6.1
4.6.2
4.6.3
4.7
4.7.1
4.7.2
4.8
4.8.1
I
SMI No. RDSO/2016/EUSMI/0293
Rev. 'O',Dated 29.07.2016
I Issued
in 2016
load. It should not exceed 14A. No load
current of motors should not exceed 1.4
A.
• Measure winding resistance of motors
between UV, VW and WU phases.
Ensure that they are balanced ± 10%.
• Spray water over running motor by jet
having 10 mm dia from all side. After
spray check IR value. It should not be
less than 10MO.
Refrigerant pipe line /Thermostatic eX_Q_ansion
valve
Check visually for proper clam_Q]n_glsu_QJ:)_ort. j_
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Ensure that thermostatic expansion valve of
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distributors to evaporator coil does not have any
sharp bend or kinks.
Evaporator/Condenser Fins
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Check that the mounting fasteners are properly -v
-v
tightened.
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Ensure that there is no damage to fins.
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-v
Clean the evaporator and condenser fins with
-v
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pressurised water and blow dry with moisture
free air at 10-15 psi.
OHP (Over heat protection), HP (High pressure), LP (Low
pressure) Cut-outs:
'.j
Disconnect blower motor through MPCB to '.j
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cause compressor tripping on low pressure (LP)
30±5 psi.
Disconnect condenser fan motor through MPCB
to cause compressor tripping in (HP) 450±15
psi.
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Check the tripping of heater through OHP by -v
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switching off the blower. The probe of digital
thermometer should be placed near the OHP
sensor and the heater should trip at 65°C.
Time Delay Relay (TOR)
'.j
Check the time setting on test bench. (180±15 -v
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sec.)
5.0 Trouble Shooting
SN
5.1
Fault/Indication
HP Trip- Glows
when
the
pressure
of
compressor
is
(Max.
high
450±15 psi).
•
•
•
•
•
•
Examine / Trouble shoot
Ensure 3-phase supply.
Check that all MCBs are ON.
Ensure availability of 11OV supply.
Check and ensure that return & supply air
opening are not obstructed or blocked.
Check air flow of condenser fan. It should be in
upward direction.
Check the suction pressure by pressure gauge
and ensure it is between 60 to 65 psi when
compressor is running.
I Page 6 of6
5.2
I SMI No. RDSO/2016/EUSMI/0293
LP Trip- Glows
the
when
of
pressure
is
compressor
Low (Min. 30±5
psi).
•
•
•
•
•
•
5.3
Compressor
trip-Glows when
compressor trips.
•
•
•
5.4
OHP trip- Glow
is
when there
excess of heat
through
heater.
(65±5°C)
•
•
5.5
Less Cooling
•
•
•
•
•
5.6
Over current
•
•
Rev. 'O',Dated 29.07.2016
I Issued in
2016
Check all MCBs and ensure 3-phase supply.
Check availability of 11 OV supply.
Check and ensure that return & supply air
opening are not obstructed or blocked.
Air flow of blower fan motor should be in
downward direction.
Feel the cooling coil by hand when compressor
is running.
Check the suction pressure by pressure gauge
and ensure it is between 60 to 65 psi when
compressor is running.
Check all MCBs and ensure 3-phase supply.
Check that supply and return air filter are clean.
Check the current of compressor. (2.0-4.0
Amp.)
Check all MCBs and ensure 3-phase supply.
Check and tighten all power lead connections at
terminals.
Air flow of blower fan motor should be in
downward direction.
Check the setting of OHP.
Check that return air filter is not blocked
Check that the current of compressor is not less
than 2.0 Amp.
If the suction pressure is less than 80 psi, when
compressor is OFF and steady state is
achieved, check leakage from joint of
compressor, HP/LP cut-outs and filter drier with
soap solution. Attend any leakage and recharge
with refrigerant as indicated in the number
plate.
Check that supply and return air filter are clean.
Check that the suction pressure is between 60
and 65 psi.
6.0 Application to Class of Locomotives:
All Electric locomotives fitted with cab AC units.
7.0 Agency of Implementation:
All Electric Loco sheds.
POH workshops
~
(~akiya)
for Director General I Electrical
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