ACA-20RM Series True-RMS-AC Ammeters with Built-in CT FEATURES N Built-in CTs provide true-rms values of complex waveforms N Perfect for measuring AC current in IT applications N Five ranges measure: 0-0.2A, 0-2A, 0-20A, 0-30A and 0-50A N 50A models features a split-core CT for easy installation N Self-powered from 85-140Vac or 170-264Vac N Large, easy-to-read, red LED display with 0.37” digits N Reliable single-board construction N Digital replacement for analog meters N UL and CSA recognized components Murata Power Solution’s new ACA-20RM Series are the world’s first digital ac-ammeters to incorporate a built-in current transformer (CT) to directly measure the true-rms value of complex, non-sinusoidal ac currents from 2 to 50A – no bulky and expensive 5A “donut” CTs are required! Operation and setup is straightforward: simply pass the load-carrying wire through the on-board CT, apply power, and the ammeter is fully operational. Five input ranges measure 0-0.2 amps (0.1mA resolution), 0-2 amps (0.001A resolution), 0-20 amps (0.01A resolution), 0-30 amps (0.1A resolution) or 0-50 amps (0.1A resolution). The 50A model features an oversized split-core current transformer that easily accommodates wires sizes up to 4 AWG (21.2mm2). Two power supply options are available: 85-140V (47-63Hz), and 170-264V (47-63Hz). All models are totally self-contained; no external components are required. Power consumption from a nominal 120V or 220V ac supply is less than 50mA. And, precision autozeroing circuitry, super-stable components, and an rms-to-dc converter circuit combine to achieve excellent performance when measuring the complex, non-sinusoidal, ac currents found in today’s computer/telecom equipment. ACA-20RM Series ammeters feature full-size, 0.37” (9.4mm) high, 3½ digit, bright red LED-displays and a built-in bezel/filter assembly that features metal fasteners. They are panel-cutout compatible with MPS’s DMS-20 Series of ac voltage and frequency monitors, making ACA-20RM ammeters perfect replacements for older, less reliable, analog panel meters in today’s sophisticated IT instrumentation. CAL. + 3½ DIGIT A/D CONVERTER – +V –V LED DISPLAY RMS-to-DC CONVERTER (L1) BUILT-IN CURRENT TRANSFORMER A B TB1 For full details go to www.murata-ps.com/rohs POWER CONVERTER MEASURED AC LOAD CURRENT www.murata-ps.com AC INPUT POWER Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_ACA-20RM_B02 Page 1 of 5 ACA-20RM Series True-RMS-AC Ammeters with Built-in CT Performance/Functional Specifications ~Specified full-scale currents are those passing through the ammeter’s built-in current transformer’s primary load-circuit. See Notes 2 and 3 below for additional model-specific information. Typical at TA = +25°C, unless otherwise noted. Min. Typ. Max. Units ACA-20RM-O-ACX-RL – – 199.9 mA ACA-20RM-1-ACX-RL – – 1.999 A ACA-20RM-2-ACX-RL – – 19.99 A ACA-20RM-4-ACX-RL – – 50.0 A ACA-20RM-5-ACX-RL – – 30.0 A Rated Full-Scale Current ~ 1.5 x Rated Full-Scale Current Overcurrent Rating Performance Sampling Rate RMS Responding, Crest Factors of 1-5 Temperature Drift (0 to 60 °C) – ±0.2 ±0.4 Cnts/°C Zero-Current Reading (within 30 sec.) –001 000 001 Cnts Dielectric Withstanding Voltage 2000 – – Vdc ACA-20RM-X-AC3-RL 85 120 140 Vac/47-63Hz ACA-20RM-X-AC4-RL 170 220 264 Vac/47-63Hz ACA-20RM-X-AC3-XX – 30 50 mA/47-63Hz ACA-20RM-X-AC4-XX – 30 50 mA/47-63Hz Power Supply Voltage Power Supply Current Power Supply Terminal Block Wire Size 16-22AWG, Solid and stranded Insulation Strip Length 0.250 inches Screw Tightening Torque 3.6 pounds-inches (0.4Nm) Rated Voltage 310Vac Display Display Type and Size 3½ Digit Red LED, 0.37”/9.4mm High Overrange Indication “1___” Decimal Point Fixed, model dependent (see full-scale input Current) Physical/Environmental Operating Temperature 0 – +60 °C Storage Temperature –40 – +75 °C Humidity –40 – +95 % Dimensions (non-condensing) Specified 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 scale. Ammeters are calibrated with a near full-scale 60Hz sine-wave current flowing through the ammeter’s built-in CT. All specified maximum power supply currents are steady state; larger surge currents can occur at initial application of line power. 2.5 Samples per second ±0.4%FS ±3 Counts with 60Hz Sine-Wave Input Accuracy Measurement Type 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, it does not apply to any external circuit-wiring or external loads. Accuracy is guaranteed up to the rated current level. Model dependent, see page 3 & 4 Ordering Information ACA-20RM- 1 - AC3 - R L - C Add -C for RoHS LED Color: RL = Low-Power Red Input Range: Power: AC3 = 85-140Vac@50/60Hz 0 = 199.9mA AC4 = 170-264Vac@50/60Hz 1 = 1.999A 2 = 19.99A 4 = 50.0A (with split-core flying-lead CT) 5 = 30.0A (with flying-lead CT) Accessories: DMS-20-CP Panel Cutout Punch TECHNICAL NOTES IMPORTANT! To ensure safe and reliable operation, ACA-20RM ammeters must be installed and serviced by qualified technical personnel after reading this data sheet in it's entirety. Contact DATEL if there is any doubt regarding their installation or operation. 1. Measurement Type: ACA-20RM ac ammeters employ true-rms input circuitry to measure the stepped-down output of their on-board current transformers (CT). Stated accuracy is measured using a sinewave input at, or close to, the specified full scale input, at a nominal line frequency of 60HZ. 2. Calibration: Periodic recalibration of ACA-20RM ammeters is not required under normal indoor environments. If user calibration is deemed necessary, it must be performed by qualified technical personnel since potentially lethal voltages and currents are applied to the ACA-20RM during the calibration process. Weight ACA-20RM-0,1,2-XXX-XX 1.1 ounces (31 grams) nominal ACA-20RM-4-XXX-XX 2.1 ounces (60 grams) nominal ACA-20RM-5-XXX-XX 1.5 ounces (43 grams) nominal www.murata-ps.com Calibration is performed with approximately 95% of the specified full-scale current flowing through the ammeter’s built-in CT. A fully insulated, non-metallic adjusting tool must be used to adjust the calibration potentiometer, located on the back of the ammeter (see Mechanical Specifications section). Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_ACA-20RM_B02 Page 2 of 5 ACA-20RM Series True-RMS-AC Ammeters with Built-in CT The calibration potentiometer has approximately ¾ of a turn of rotation; do not force its adjustment screw past the end stops. Contact MPS if additional information is required regarding calibration, setup, or any other technical issue pertaining to ACA-20RM ac ammeters. 3. Wire Gauges and Fusing: Use only the wires specified under the Functional Specifications Section when making connections to ACA20RM Series ammeters. All power supply and load wiring must be adequately rated for the supply voltages and currents they will carry, and they must comply with all code- or application-mandated requirements pertaining to the user’s installation. The supply wires connected to ACA-20RM ammeters must be fused in accordance with applicable regulatory codes. Also, wire insulation should be stripped to within +/-10% of the stated dimensions; wires should be inserted into TB1 such that the screw terminal does not pinch their insulation. TB1 can only used for supplying power to the meter’s internal circuitry; it must not be used to supply current to external loads. AC-powered models draw minimal steady-state supply currents (less than 0.050A) and they can be fused according to the supply wire’s maximum amperage rating. However, these models can draw higher surge currents for brief periods (in the microsecond range) when power is initially applied. 4. AC Supply Polarity and Grounding: The two supply inputs, TB1 ‘A’ and ‘B’, on ACA-20RM ammeters are not polarity sensitive, that is, they have no ‘AC LO’ or ‘AC HI’ designations. Also, ac-powered ACA-20RM ammeters do not include or require a connection to earth/ chassis ground. 5. Connector Torque Ratings: Be sure to tighten TB1’s screw-terminals to 3.6 pound-inches (0.4Nm). Proper tightening will ensure reliable long-term operation. 6. Isolation: The on-board CT (L1) provides a minimum of 2000Vdc isolation between the current-carrying load conductor passing through its opening and the ammeter’s power source that’s connected to TB1. Of course, this isolation rating applies only to applications where the load wire does not connect directly or indirectly to TB1-A or TB1-B (i.e., where two different ac supplies are involved). 7. Split-Core CT (Clamp-on) Models: 50A models feature a split-core current transformer that can be clamped around a current-carrying load conductor without having to disconnect or remove power from the load’s power source. This live-connection capability can only be used if the load’s power source is isolated (see technical note 6) from the ammeter’s own power source that’s connected to TB1. The ammeter’s ac power supply must always be denergized before making connections to TB1. Refer to the ‘Panel Installation’ section of this data sheet for additional information. WIRING DIAGRAMS First pass and carefully dress one external load wire through L1, then connect the AC supply and load wires to TB1 as shown. Ensure all wires are stripped and properly tightened. For accurate operation, make only one pass with load wire through the on-board CT (only one primary turn). For split-core CT models, make sure to fully engage the CT's Locking mechanism BACK VIEW BACK VIEW A A FUSED AC POWER TB1 FUSED AC POWER B TB1 B TO AC LOAD L1 L1 TO AC LOAD FROM AC SUPPLY Figure 2. Connections for pc-board mounted CT's FROM AC SUPPLY Figure 3. Connection for flying lead CT's www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_ACA-20RM_B02 Page 3 of 5 ACA-20RM Series True-RMS-AC Ammeters with Built-in CT PANEL INSTALLATIONS All connections to ACA-20RM Series ammeters must be made after the ammeter is securely attached to its panel and with all associated load and supply voltages de-energized (off). However, using extreme caution and observing all safety measures applicable to the user’s installation, 50A split-core CT models can be connected to energized current-carrying load conductors, but connections to TB1 must always be made with the ammeter’s power source off. Using Figure 4 as a guide, carefully insert the bezel/color filter assembly into the panel opening. From the rear of the panel, install the four round plastic standoffs over the bezel’s threaded studs. Install the pc-board assembly then attach and securely tighten all four hex nuts. 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 ammeter itself. The recommended range of panel thickness that can be used with the supplied hardware is 0.040 inches (1.0mm) to 0.125 inches (3.2mm). Panel thickness outside of this range will require additional user-supplied hardware and/or modifications. Care should be exercised when passing the load-carrying conductor through the meter’s built-in CT---particularly when larger conductors are used. The installed wire-positions should be such that minimal mechanical forces are applied to the built-in CT, TB1, or to the ammeter itself. In high-vibration environments, it is strongly recommended that adequate strain reliefs be used for all load and supply wiring. PANEL 3TANDOFF 'ASKET 4HICK 'ASKET .UT 3TANDOFF "OARD#UTOUT "EZEL !#!2!#!MMETER 3)$%6)%7 Figure 4. Panel Installation BEZEL AND PANEL CUTOUT RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS 0.187 (4.75) 0.55 (13.97) FRONT VIEW 1.280 (32.51) INTERNAL CORNER RADII: 0.032 (0.81) MAX. 1.07 (27.18) 0.116 (2.95) 0.838 (21.29) 1.336 (33.93) 0.145 (3.68) 1.826 (46.38) 1.626 (41.30) 0.093 (2.362) DIAMETER (4 REQUIRED) www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_ACA-20RM_B02 Page 4 of 5 ACA-20RM Series True-RMS-AC Ammeters with Built-in CT MECHANICAL SPECIFICATIONS ,%!$%$30,)4#/2%#4-/$%,3 &2/.46)%7 ,%!$%$#4-/$%,3 &2/.46)%7 2.100 (53.34) 2.100 (53.34) - - - 0#"/!2$-/5.4%$#4-/$%,3 &2/.46)%7 2.100 (53.34) - - - 1.400 (35.56) 1.400 (35.56) 1.750 (44.45) "!#+6)%7 "!#+6)%7 "!#+6)%7 CAL TB1 Lead Length 5.0 (127.0) min. L1 Lead Length 2.0 (50.5) min. 0.35 (8.9) Diameter 1.575 (40.00) 0.40 (10.2) Diameter 3)$%6)%7 3)$%6)%7 0.26 (6.6) Diameter 0.984 (24.99) 3)$%6)%7 0.250 (6.35) 1.024 (26.01) 0.250 (6.35) 0.250 (6.35) 0.480 (12.19) 0.551 (14.00) 1.00 (2.54) For 2A and 20A Models MECHANICAL DIMENSIONS: Inches (mm) TOLERANCES: 2 PL DEC ±0.02 (±0.51) 3 PL DEC ±0.010 (±0.254) 0.480 (12.19) USA: Murata Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 www.murata-ps.com email: [email protected] ISO 9001 and 14001 REGISTERED 12/23/08 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. © 2008 Murata Power Solutions, Inc. www.murata-ps.com Mansfield (MA), Tel: (508) 339-3000, email: [email protected] Canada: Toronto, Tel: (866) 740-1232, email: [email protected] UK: Milton Keynes, Tel: +44 (0)1908 615232, email: [email protected] France: Montigny Le Bretonneux, Tel: +33 (0)1 34 60 01 01, email: [email protected] Germany: München, Tel: +49 (0)89-544334-0, email: [email protected] Japan: Tokyo, Tel: 3-3779-1031, email: [email protected] Osaka, Tel: 6-6354-2025, email: [email protected] China: Shanghai, Tel: +86 215 027 3678, email: [email protected] Guangzhou, Tel: +86 208 221 8066, email: [email protected] Singapore: Parkway Centre, Tel: +65 6348 9096, email: [email protected] Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_ACA-20RM_B02 Page 5 of 5