ACA-20RM-ALM Series
True-rms-AC Ammeters with Alarm Function
FEATURES
User–settable, visual alarm function
Flashing display indicates overcurrent faults
Measures the true-rms value of complex ac current
waveforms
Includes built-in current transformers
Ideal for measuring current in sensitive IT applications
Available in two input ranges: 0-30.0A, and 0 to 50A
50A model features convenient split-core CT
Easy-to-read, red LED display with 0.37"/9.4mm high
digits
Two AC power options: 85-140Vac & 170-264Vac
(50/60Hz)
2000V isolation between ac supply and load conductor
Murata Power Solutions’ ACA-20RM-ALM Series digital ac ammeters accurately display
the true-rms value of non-sinusoidal ac currents and provide a user-settable, over current
alarm function. When the preset over current level is exceeded, the LED display continu-
ously flashes from high to low intensity. All models are totally self-contained—no other
user-supplied components are required. A built-in current transformer greatly simplifies
most ac ammeter applications: just pass the load conductor through the built-in current
transformer, apply ac power, and the ammeter is fully operational.
Two input ranges are available: 0-30.0 Amps, or 0 to 50.0 Amps, both with 0.1A resolu-
tion. The 50 Amp model features a convenient split-core type current transformer which
can be clamped around insulated live conductors. Two power supply options are available:
85-140V (47-63Hz), and 170-264V (47-63Hz). Power consumption from a nominal 120V or
220V ac supply is less than 50mA. Super-stable components and an rms-to-dc converter
circuit combine to achieve excellent performance when measuring the complex, non-sinu-
soidal, ac currents found in today’s computer/telecom equipment.
All ACA-20RM-ALM Series true-rms ammeters feature full-size, 0.37" (9.4mm) high,
3�½ digit, bright red LED-displays and a built-in bezel/filter assembly that includes metal
fasteners. They are also panel cutout compatible with MPS’s DMS-20RM Series of rms-
reading ac voltage monitors, making ACA-20RM-ALM ammeters the ideal upgrade for
today’s sophisticated instrumentation.
CAL.
+
3�½ DIGIT
A/D CONVERTER
–
+V
rms-to-DC
CONVERTER
–V
LED DISPLAY
(L1)
POWER
CONVERTER
BUILT-IN
CURRENT
TRANSFORMER
A
B
TB1
For full details go to
www.murata-ps.com/rohs
MEASURED AC
LOAD CURRENT
AC INPUT POWER
Figure 1. ACA-20RM-ALM Series simplified schematic
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MPM_ACA-20RM-ALM.A01
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MURATA-PS [ MURATA POWER SOLUTIONS INC. ]
