Murata | MULTI-7000 | ACM3P Series - Murata Power Solutions

ACM3P Series
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s
Three-Phase AC Ammeters
Actual size
C
®
US E156931
FEATURES
PRODUCT OVERVIEW

Measure and display the true-rms current of 3-phase
power systems

Universal 85-264Vac (47-63Hz) operating supply
range

Three built-in current transformers measure up to
100A per phase

Ideal for power distribution units (PDUs) and backup
power systems

Low power consumption: less than ¼watt from
120Vac supply

One-piece polycarbonate housing fits ‘0U’ & ‘1U’
rack spaces

Low-profile surface mount design occupies minimal
behind-the-panel space

Available in red, green, or blue LED-displays with
phase annunciators
Murata Power Solutions’ ACM3P series 3-phase AC ammeters measure and display the
true-rms values of 2- or 3-phase ac mains current. A front panel touch switch enables the
selection of a continuous reading of any of the three phases. All ACM3P ammeters are functionally complete, with built-in L1, L2, and L3 current transformers—no other user-supplied
components or hardware are required.
ACM3P series AC ammeters are available with a 0-100A input range (150A peaks) and
provide a resolution of 0.1 Amp. Their 85-264Vac (47-63Hz) operating supply range makes
these ammeters perfect for worldwide 3-phase current monitoring applications. And, unlike
conventional average-responding products, ACM3P ammeters can accurately display the
true-rms values of triangle waves, square waves, and other irregularly shaped AC current
waveforms, with an accuracy of ±2% of full scale.
Their large (0.36"/9.2mm), bright LED display, available in a choice of red, blue, or green,
enables ACM3P ammeters to be easily readable from as far as 15 feet (5 meters). All
units are packaged in a one-piece, vibration resistant, polycarbonate housing that can be
installed in vertical ‘0U’ or horizontal ‘1U’ rack spaces. Their miniature size is ideal for UPS
backup power sources, power strips, alternative energy metering, and any other applications that require precise monitoring of 2- or 3-phase ac current.

Low Cost; approvals to UL/cUL/IEC/61010-1
SIMPLIFIED SCHEMATIC DIAGRAM
L1
L2
L3
PHASE 1
+5V
PHASE 2
L1
L2
PHASE 3
A/D
CONVERTER
L3
+5V
CURRENT
LIMITED
85-264 Vac
47-63 Hz
SUPPLY
B
A
+5V
AC/DC
CONVERTER
MICROCONTROLLER
For full details go to
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SEL
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MPM_ACM3P Series.A04 Page 1 of 6
ACM3P Series
Three-Phase AC Ammeters
Performance/Functional Specifications
Typical at TA=+ 25ºC, 120Vac @ 50Hz, unless otherwise noted
Measurement Limits
Min.
Typ.
Max.
Units
AC (rms) Current, L1, L2, L3 ➀
0.0
—
100.0
Amperes
Overcurrent Rating ➁
1.5 x Rated full-scale current
Performance
Sampling Rate
1.5 samples/sec
Current Accuracy ➂
±2%
Measurement Bandwidth (L1, L2, L3)
±3%
14kHz
Temperature Drift (0 to 60ºC)
0.5 Counts/ºC
Zero-Current Reading (within 1 sec.)
1
UL/IEC61010-1
Counts
Measurement category II
Supply Voltage (TB1)
All Models
85
120
264
Vac/47-63Hz
ACM3P-X-AC1-R-X-C
35
50
110
mA
ACM3P-X-AC1-G-X-C
50
75
165
mA
ACM3P-X-AC1-B-X-C
50
75
165
mA
Supply Current ➃
Power Supply Terminal Block (TB1)
Wire Size
16-22AWG, solid or stranded
Insulation Strip Length
6.4mm (0.250 in)
Screw Tightening Torque
0.4Nm (3.6 lb-in)
Rated Voltage
Display
4 Digit LED, 9.14mm (0.36in) high
Overrange Indication
Flashing display
Decimal Point Selection
Automatically Set
Physical/Environmental
Operating Temperature:
Storage Temperature:
Humidity (non-condensing):
Dimensions:
0
—
+60
ºC
-40
—
+75
ºC
0
—
85
%
See mechanical specifications
Weight, all models
2.6 oz (74g)
Notes
➀ Specified full-scale currents are those passing through the power meter’s built-in current
transformer’s primary load-circuit. See Notes 2 and 3 below for additional information.
➁ The overcurrent rating of 1.5 x the rated full-scale current is a continuous rating and applies to
the current passing through the built in current transformer. Accuracy is guaranteed up to the
rated current level.
➂ Power Meters are calibrated with near full-scale 50Hz sine-wave inputs.
➃ All specified maximum supply currents are steady state. Larger surge currents can occur at
initial application of line power.
ORDERING INFORMATION
ACM3P-4-AC1-R-C
100A, 85-264Vac Supply, Red LED Display
ACM3P-4-AC1-G-C
100A, 85-264Vac Supply, Green LED Display
ACM3P-4-AC1-B-C
100A, 85-264Vac Supply, Blue LED Display
!
IMPORTANT! To ensure safe and reliable operation, ACM3P ammeters must be installed and serviced by qualified technical personnel.
Contact Murata Power Solutions if there is any doubt regarding their
installation or operation.
1. Measurement Type: ACM3P series 3-phase ammeters employ a
precision energy metering integrated circuit and a low-power microcontroller to measure and display the rms value of 2- or 3-phase
ac-mains current. However, while the unit has an upper bandwidth
of 14kHz, dc components or frequencies below 47Hz will not be
measured accurately.
2. Basic Operation: Upon application of ac power to TB1, the unit
will first perform a self-test routine and then continuously display
amperes, with one of the three phase-annunciator LEDs illuminated
(L1, L2, or L3). The display will remain fixed in one of these reading
modes as long as the front panel ‘SEL’ button is not touched. Assuming phase L1 is initially illuminated, momentarily touching the ‘SEL’
button two times in succession will cycle the display to phase L2, and
then to phase L3. Momentarily touching ‘SEL’ a third time will return
the unit back to displaying phase L1 current.
If power is removed and then restored, the ACM3P will perform a
self-test and then return to displaying the last selected phase, i.e.,
the phase it displayed just before power was removed.
300Vac
Display Type and Size
TECHNICAL NOTES
Configuring for 2-Phase Operation: As shipped, ACM3P ammeters
are configured to measure and display 3-phase currents (L1, L2, and
L3 current transformers are all active). The unit can be set to display
2-phase currents (only L1 and L2 are active) by performing the following procedure:
A. Press and hold the SEL button for approximately five seconds and
then release the button once the words “LinE SEt” appear on the
display.
B. Briefly tapping the SEL button will alternate the display reading
between ‘2-Ph’ and ‘3-Ph’ each time SEL is tapped.
C. To change the factory default 3-phase mode to 2-phase, leave the
display fixed in the ‘2-Ph’ reading for at least five seconds.
To revert the unit back to 3-phase operation simply repeat the above
procedure but, in step C, allow the unit to display a fixed ‘3-Ph’ for at
least five seconds.
3. Overrange Indication: ACM3P ammeters have an overcurrent rating of 1.5 times rated current, or 150A. However, accuracy is only
guaranteed up to 100A, and the display will flash on and off when the
current is at or above 120A.
4. Calibration: Due their digital design, ACM3P ammeters cannot be
calibrated in the field. ACM3P ammeters are factory-calibrated to
meet their specified accuracies with the factory supplied current
transformers. Use of any other current transformers will produce
significant errors.
Contact Murata Power Solutions if additional information is required
regarding calibration, setup, or any other technical issue pertaining to
ACM3P ammeters.
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MPM_ACM3P Series.A04 Page 2 of 6
ACM3P Series
Three-Phase AC Ammeters
TECHNICAL NOTES, CONTINUED
8. Connector Torque Ratings: It is important to tighten TB1’s screwterminals to their rated torque specification of 3.6 pound-inches
(0.4Nm). Proper tightening will minimize connector losses and ensure
safe, reliable operation.
5. Wiring: All power supply and load wiring must be rated for the voltages and currents they will carry and must comply with any code or
application-mandated requirements pertaining to the user’s specific
installation.
9. Isolation: Except for the 2-56 thread metallic mounting studs, all of
the ACM3P ammeter’s internal components (printed circuit board,
resistor, capacitors, current transformers L1, L2 and L3’s secondary
leads, etc.) are at the ac-mains potential connected to TB1. ACM3P
ammeters are designed to be powered from one ac power-source
only. Any other connection schemes could introduce significant measurement errors.
6. Supply Fusing, and Grounding: Wires specified in the Functional
Specifications section must be used for making connections to ACM3P series ammeters’ TB1 terminal block. No connection is required
for earth/chassis ground.
ACM3P series ammeters are not internally fused. Terminal block TB1
is to be used only for powering the ammeter's internal circuitry; it
must not be used to supply power to external loads. The supply wires
feeding these power meters must be fused with a 0.5A/250V time
delay/time lag fuse, in accordance with applicable regulatory codes.
Wire insulation must be stripped to within ±10% of the stated dimensions, and wires should be inserted into TB1 such that their insulation
is not pinched by the screw terminal.
7. Current Transformer Phasing: Since the ACM3P only measures
amperes, transformer phasing is not required. ‘Phasing’ refers to the
direction of the current-carrying wire as it passes through the primary
hole of each of the three built-in current transformers.
The three built-in current transformers have a dielectric breakdown
rating of 2kV minimum, allowing them to safely monitor 480V,
3-phase ac mains currents. This dielectric rating pertains only to the
insulated load-carrying wire as it passes through the built-in CT’s
primary hole. However, attention must still be paid to ensure adequate
wire-to-wire spacings, and wire-to-metallic surface spacings. Properly rated wiring and fusing must be used for all installations, as noted
in Technical Notes 5 and 6 above.
IMPORTANT: Even though ACM3P ac ammeters can be used in 480V
current monitoring applications, the ac supply connected to TB1 must
never exceed the maximum rating of 264V/47-63Hz.
PANEL INSTALLATION
PANEL
2-56 Hex Nuts (4 places)
Tighten each nut to 15 to 20
ozf-in (0.106 to 0.140 N-m).
ACM3P
Panel Cutout
L1
L2
L3
SIDE VIEW
All connections to ACM3P ammeters must be made after the unit is
securely attached to the panel, and with all associated load and supply voltages de-energized (off), using extreme caution and observing
all safety measures applicable to the user’s installation.
Care should be exercised when passing conductors through the
ammeter’s built-in current transformers L1, L2, and L3. The installed
wire-positions should be such that minimal mechanical forces are
applied to the current transformers, TB1, or to the ACM3P ammeter
itself. In high-vibration environments, it is strongly recommended that
strain reliefs be used for all wiring.
Using Figure 1 as a guide, carefully insert the ACM3P assembly into
the panel opening. From the rear of the panel, install and then tighten
the four #2-56 hex nuts over the threaded studs. Tighten each nut to
15 to 20 ozf-in (0.106 to 0.140 N-m). Use only the factory-supplied
hardware as the use of substitute hardware could result in an unsafe
installation and/or adversely affect the reliability of the installation.
The recommended panel thickness range that can be used with the
supplied hardware is 0.040 inches (1.0mm) to 0.25 inches (6.4mm).
Panel thicknesses outside of this range may require additional usersupplied hardware or modifications.
Figure 1. Panel Installation
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MPM_ACM3P Series.A04 Page 3 of 6
ACM3P Series
Three-Phase AC Ammeters
TYPICAL WIRING DIAGRAMS
PHASE A
PHASE B
L1
L2
L1
L2
B
TB1
A
L3
Note: Line and phase currents
are the same for Wye systems.
Fuse*
L3
PHASE C
85–264 Vac
47–63 Hz
Figure 2. Wiring diagram Wye systems
*See technical note 6.
L1
PHASE A
L1
L2
PHASE B
B
L2
TB1
A
L3
Fuse*
L3
PHASE C
85–264 Vac
47–63 Hz
Figure 3. Wiring diagram for Delta systems monitoring line current
*See technical note 6.
PHASE B
L1
L2
L2
B
L1
TB1
A
L3
PHASE A
PHASE C
Fuse*
L3
85–264 Vac
47–63 Hz
Figure 4. Wiring diagram for Delta systems monitoring phase current
*See technical note 6.
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MPM_ACM3P Series.A04 Page 4 of 6
ACM3P Series
Three-Phase AC Ammeters
PANEL CUTOUT
RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS
INTERNAL CORNER RADII:
0.032 (0.81) MAX.
1.07
(27.18)
The panel opening must be centered vertically and
horizontally between the four 0.093 (2.362mm)
diameter holes.
0.870
(22.10)
1.426
(36.22)
1.626 (41.30)
0.093 (2.362) DIAMETER (4 REQUIRED)
MECHANICAL SPECIFICATIONS
2.10 (53.3)
0.51
(12.95)
Dimensions are in inches (mm).
0.12 (3.05) (min)
1.43
(36.3)
L1
L2
L3
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.51)
.XXX ± 0.010 (0.254)
Angles ± 2˚
1.07
(27.20)
Side View
Components are shown for reference only.
SEL
MULTI-PHASE AC AMMETER
0.40
(10.16)
Front View
0.12 (3.05) (min)
L1
Lead Length
5.0 (127) min.
0.22 (5.59)
(min)
1.63
(41.4)
B
TB1
A
0.33 (8.39)
(min)
L3
Bottom View
0.086 DIA (REF)
2-56 UNC THREAD
L2
0.60
(15.24)
(max)
Back View
Diameter:
Inner: 0.57 (14.5)
Outer: 1.175 (29.8)
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MPM_ACM3P Series.A04 Page 5 of 6
ACM3P Series
Three-Phase AC Ammeters
1. Description of safety marks:
Caution, risk of electrical shock
Caution, risk of danger
Equipment is protected throughout by double or reinforced insulation
2. Cleaning Instructions: Gently clean with dry cloth only.
3. Caution: if the equipment is used in a manner not specified by Murata Power Solutions, the protection provided by the equipment may be impaired.
NOTES
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other
technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply
the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without
notice.
© 2014 Murata Power Solutions, Inc.
www.murata-ps.com/support
MPM_ACM3P Series.A04 Page 6 of 6
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