www.murata-ps.com ACA-20RM-ALM Series True-rms-AC Ammeters with Alarm Function C US E156931 FEATURES 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 Usersettable, visual alarm function alarm function. When the preset over current level is exceeded, the LED display continu- Flashing display indicates overcurrent faults ously ashes from high to low intensity. All models are totally self-containedno other Measures the true-rms value of complex ac current user-supplied components are required. A built-in current transformer greatly simpli es waveforms most ac ammeter applications: just pass the load conductor through the built-in current transformer, apply ac power, and the ammeter is fully operational. Includes built-in current transformers Two input ranges are available: 0-30.0 Amps, or 0 to 50.0 Amps, both with 0.1A resolu- Ideal for measuring current in sensitive IT applications tion. The 50 Amp model features a convenient split-core type current transformer which Available in two input ranges: 0-30.0A, and 0 to 50A 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 50A model features convenient split-core CT 220V ac supply is less than 50mA. Super-stable components and an rms-to-dc converter Easy-to-read, red LED display with 0.37 /9.4mm high circuit combine to achieve excellent performance when measuring the complex, non-sinu- digits soidal, ac currents found in todays computer/telecom equipment. Two AC power options: 85-140Vac & 170-264Vac All ACA-20RM-ALM Series true-rms ammeters feature full-size, 0.37 (9.4mm) high, (50/60Hz) 3 digit, bright red LED-displays and a built-in bezel/ lter assembly that includes metal fasteners. They are also panel cutout compatible with MPSs DMS-20RM Series of rms- 2000V isolation between ac supply and load conductor reading ac voltage monitors, making ACA-20RM-ALM ammeters the ideal upgrade for Approvals to UL/cUL/IEC/61010-1 todays sophisticated instrumentation. CAL. + 3 DIGIT A/D CONVERTER +V V LED DISPLAY RMS-to-DC CONVERTER POWER CONVERTER (L1) BUILT-IN AB CURRENT TRANSFORMER TB1 MEASURED AC CURRENT LIMITED For full details go to LOAD CURRENT AC SUPPLY www.murata-ps.com/rohs Figure 1. ACA-20RM-ALM Series simpli ed schematic www.murata-ps.com/support MPM ACA-20RM-ALM.B01 Page 1 of 5ACA-20RM-ALM Series True-rms-AC Ammeters with Alarm Function Performance/Functional Speci cations Speci ed full-scale currents are those passing through the ammeters built-in current transformers primary load-circuit. See Notes 2 and 3 below for ad- Typical at TA = +25C, unless otherwise noted. ditional model-speci c information. Min. Typ. Max. Units Rated Full-Scale Current 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 only, ACA-20RM-4-ACX-RL-ALM 50.0 Amperes it does not apply to any external circuit-wiring or external loads. Accuracy is ACA-20RM-5-ACX-RL-ALM 30.0 Amperes guaranteed up to the rated current level. 1.5 x Rated Full-Scale Current Overcurrent Rating Speci ed accuracy applies to inputs with crest factors (CF) up to 2.0, where CF = Vpeak/Vrms. Crest factors of 2 to 5 introduce an additional error of 3% of full Performance scale. Ammeters are calibrated with a near full-scale 60Hz sine-wave current Sampling Rate 2.5 Samples per second owing through the ammeters built-in CT. 0.4%FS 3 Counts with 60Hz All speci ed maximum power supply currents are steady state larger surge Accuracy currents can occur at initial application of line power. Sine-Wave Input Measurement Type rms Responding, Crest Factors of 1-5 Ordering Information Temperature Drift (0 to 60 C) 0.2 0.4 Counts/C ACA-20RM-4-AC3-RL-ALM-C 50.0A Range (split-core CT), 85-140Vac power ACA-20RM-4-AC4-RL-ALM-C 50.0A Range (split core CT), 170-264Vac power Zero-Current Reading (within 001 000 001 Counts 30 sec.) ACA-20RM-5-AC3-RL-ALM-C 30.0A Range, 85-140Vac power ACA-20RM-5-AC4-RL-ALM-C 30.0A Range, 170-264Vac power Dielectric Withstanding Voltage 2000 Vdc UL/IEC61010-1 Measurement category II See www.murata-ps.com/dpm-availability for model-speci c availability. Power Supply Voltage TECHNICAL NOTES ACA-20RM-X-AC3-RL-ALM 85 120 140 Vac/47-63Hz IMPORTANT To ensure safe and reliable operation, ACA-20RM- ACA-20RM-X-AC4-RL-ALM 170 220 264 Vac/47-63Hz ALM ammeters must be installed and serviced by quali ed Power Supply Current technical personnel. Contact Murata Power Solutions if there is ACA-20RM-X-AC3-RL-ALM 30 50 mA/47-63Hz any doubt regarding ammeter setup, installation, or operation. ACA-20RM-X-AC4-RL-ALM 30 50 mA/47-63Hz 1. Measurement Type: ACA-20RM-ALM ac ammeters employ a Alarm Function true-rms input circuit to measure current owing through L1. Stated Flashing Display with actual current accuracy speci cations are measured using a sine-wave current Display indication reading and display intensity change at, or close to, the ammeters full-scale input range, at nominal line Settable range frequency of 60Hz. ACA-20RM-4-ACX-RL-ALM 13 45 50 Amps 2. Calibration (Potentiometer R7): Periodic recalibration of ACA- ACA-20RM-5-ACX-RL-ALM 8 24 30 Amps 20RM-ALM ammeters is not required under normal, indoor operating Power Supply Terminal Block environments. If user calibration is necessary, it must be performed by quali ed technical personnel. Calibration is performed with poten- Wire Size 16-22AWG, Solid or stranded tially lethal voltages applied to the ACA-20RM-ALM and its associated Insulation Strip Length 0.250 inches wiring. A plastic, fully-insulated adjusting tool must be used to access Screw Tightening Torque 3.6 pounds-inches (0.4Nm) the calibration potentiometer R7 located on the back of the ammeter Rated Voltage 310Vac (see Mechanical Speci cations section). Contact MPS if additional Display information is required regarding calibration, setup, or any other technical issue pertaining to ACA-20RM-ALM ammeters. Display Type and Size 3 Digit Red LED, 0.37/9.4mm High Overrange Indication 1 3. Overcurrent Alarm Setup and Adjustment (Potentiometer R3): ACA-20RM-ALM ammeters feature a user-settable, overcurrent visual Fixed, model dependent Decimal Point (see full-scale input current) alarm indication which can be used to alert operators that a load cir- cuit breaker or fuse is approaching an overload condition. When the Physical/Environmental load current sensed by L1 exceeds this preset level, the ammeters Operating Temperature 0 +60 C LED display will ash from normal intensity to dim intensity at rate of Storage Temperature 40 +75 C approximately 1.5 times per second. Humidity (non-condensing) 0 85 % As shown in Figure 3, the alarm circuit consists of jumper JP1, and Dimensions Model dependent, see page 4 & 5 adjustment potentiometer R3. As shipped, R3 is factory set to trip Weight when the load current is approximately 24 Amps for 30A models, and ACA-20RM-4-XXX-XX-ALM 1.5 Ounces (43 grams) nominal approximately 45 Amps for 50A models. When R3 is set to its maxi- mum clockwise position, the alarm indication will not activate until the ACA-20RM-5-XXX-XX-ALM 2.1 Ounces (60 grams) nominal load current owing through L1 exceeds the maximum rating of the ammeter, i.e., above 30.0A, or above 50.0A, depending on the model. www.murata-ps.com/support MPM ACA-20RM-ALM.B01 Page 2 of 5