ACA5-20RM Series True-rms-AC Ammeters with 5A CT Inputs FEATURES N Scales and displays the true-rms output of 5A current transformers N Accurately measure complex ac current waveforms N Perfect for measuring current in IT applications N Available in three input ranges: 0-100A, 0 to 200A, or 0 to 500A N Functionally complete: On-board, low-burden toroid sensor Scaling/interface circuitry Precision A/D converter N Reliable single-board construction N Easy-to-read, red LED display with 0.37"/9.4mm digits N Two AC power options: 85-140Vac & 170-264Vac (50/60Hz) N 2000V isolation between ac supply and external CT N Digital replacement for analog meters Murata Power Solutions’ ACA5-20RM Series accept the output of external 5A current transformers (CTs) and accurately display the true-rms value of complex, non-sinusoidal ac currents up to 500A. Operation and setup is straightforward: simply pass the external 5A CT’s secondary 0-5A output leads through the ACA5-20RM’s on-board toroid sensor, apply ac power, and the ammeter is fully operational. All models are totally self-contained—other than the external 5A CT, no other user-supplied components are required. Three input ranges measure 0-100.0 amps (with 0.1A resolution), 0-200 amps (0.1A resolution), and 0-500 amps (1A resolution). 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. And, precision auto-zeroing 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. ACA5-20RM Series rms 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 also panel-cutout compatible with Murata Power Solutions’ DMS-20RM Series of rms-reading ac voltage monitors, making ACA5-20RM ammeters perfect replacements for older, less reliable, analog voltmeters and ammeters in today’s sophisticated instrumentation. PRECISION rms-to-DC CONVERTER BUILT-IN TOROID SENSOR L1 A B TB1 For full details go to www.murata-ps.com/rohs Figure 1. ACA5-20RM Series simplified schematic www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_ACA5-20RM.A01 Page 1 of 5 ACA5-20RM Series True-rms-AC Ammeters with 5A CT Inputs Performance/Functional Specifications ~ The specified full-scale current is the ac current circulating through the meter’s built-in 5A current transformer’s primary circuit L1 (i.e., the external current transformer’s 0-5A output current). Typical at TA = +25°C, unless otherwise noted. Full-Scale Primary Current ~ All Models Min. Typ. Max. Units – – 5.0 rms Amps 1.5 x Rated full-scale rms current Overcurrent Rating Display Readings with 5A Flowing through the Ammeter’s Current Transformer Model Number Display Reading ACA5-20RM-3-ACX-RL 100.0 ACA5-20RM-5-ACX-RL 199.9 ACA5-20RM-9-ACX-RL 500 The overcurrent rating of 1.5 times the rated full-scale current is a continuous rms rating and applies to the current passing through the built in current transformer (CT). Accuracy is only guaranteed up to the rated full-scale CT current of 5Arms. 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 5.00Arms/60Hz current flowing through the ammeter’s built-in 5A CT. All specified maximum power supply currents are steady state; larger surge currents can occur at initial turn-on. Performance Sampling Rate 2.5 Samples per second ±0.4%FS ±3 Counts with 60Hz Sine-Wave Input Accuracy Input Frequency Range 47–63 Ordering Information ACA5-20RM-3-AC3-RL-C ACA5-20RM-3-AC4-RL-C 100.0A Range, 85-140Vac power 100.0A Range, 170-264Vac power ACA5-20RM-5-AC3-RL-C ACA5-20RM-5-AC4-RL-C 199.9A Range, 85-140Vac power 199.9A Range170-264Vac power ACA5-20RM-9-AC3-RL-C ACA5-20RM-9-AC4-RL-C 500A Range, 85-140Vac power 500A Range, 170-264Vac power Hz Measurement Type 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 Breakdown Voltage 2000 – – Vdc ACA5-20RM-X-AC3-RL 85 120 140 Vac/47-63Hz ACA5-20RM-X-AC4-RL 170 220 264 Vac/47-63Hz ACA5-20RM-X-AC3-RL — 30 50 mA/47-63Hz ACA5-20RM-X-AC4-RL — 30 50 mA/47-63Hz Power Supply Voltage Accessory Current Transformers for above*: Power Supply Current 7020-01038-0 7020-01040-0 39-3681409 100A Current Transformer, RoHS compliant 200A Current Transformer, RoHS compliant 500A Current Transformer, not RoHS compliant * See data sheet titled “Current Transformers” at www.murata-ps.com for more information Power Supply Terminal Block (all models) Wire Size 16-22AWG, Solid or 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___” Model dependent; see “Display Readings” above Display Reading/Decimal Point Physical/Environmental Operating Temperature Storage Temperature Humidity (non-condensing) Dimensions 0 – +60 °C –40 – +75 °C – – 85 % Model dependent, see page 4 & 5 Weight All models 1.1 Ounces (31 grams) nominal www.murata-ps.com TECHNICAL NOTES IMPORTANT! To ensure safe and reliable operation, ACA5-20RM ammeters must be installed and serviced by qualified technical personnel. Contact Murata Power Solutions if there is any doubt regarding ammeter installation and/or operation. 1. Measurement Type: ACA5-20RM ac ammeters employ a true rms input circuit to measure the output of external 5A current transformers. Stated accuracy specifications are measured using a sine-wave current at, or close to, the full-scale input range, at nominal line frequency of 60Hz. 2. Calibration: Periodic recalibration of ACA5-20RM ammeters is not required under normal, indoor operating environments. If user calibration is necessary, it should be performed by qualified technical personnel. Calibration is performed with potentially lethal voltages applied to the ACA5-20RM and its associated wiring, with 5.0 amps flowing through the ammeter’s built-in toroid sensor. A plastic, fully-insulated adjusting tool must be used to access the calibration potentiometer located on the back of the meter (see Mechanical Specifications). Contact MPS if additional information is required regarding calibration, setup, or any other technical issue pertaining to ACA5-20RM ammeters. Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_ACA5-20RM.A01 Page 2 of 5 ACA5-20RM Series True-rms-AC Ammeters with 5A CT Inputs 3. Wire Gauges and Fusing: Wires specified in the Functional Specifications section must be used for making connections to ACA5-20RM Series ammeters. All power-supply and load wiring must be rated for the supply voltages and currents they will conduct and must comply with any code or application-mandated requirements pertaining to the user’s specific installation. 6. Isolation: The built-in toroid sensor (L1) provides a minimum of 2000Vdc isolation between the external CT’s 5A secondary conductors and the ammeter supply voltage connected to TB1. 7. CT Precautions: In normal operation, a 5A CT’s secondary circuit operates at a very low voltage due to its closed-loop operation and low burden resistance. However, a CT can still generate potentially lethal voltages if its output current is suddenly interrupted. For example, loose 5A CT secondary connections can cause a condition referred to as “inductive kick”. Inductive kick can generate extremely high voltages across a CT’s intermittent secondary connections. The supply wires connected to both the ammeter and the load must be fused according to the current rating of the wire gauge being used, in accordance with applicable regulatory codes. Also, wire insulation should 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. TB1 is to be used only for powering the meter’s internal circuitry; It must not be used to supply current to any external loads. Therefore, implementing connections to any 5A current transformer’s output leads must only be performed with zero load-current flowing the CT’s primary load-circuit. 8. CT Connections and Grounding: Some applications require connecting one of the external 5A CT’s output leads to earth/chassis ground. In the USA, consult the latest revision of the National Electrical Code (NEC) for more information regarding CT grounding. All models draw minimal steady-state supply currents (50mA max.), and in most applications they can be fused according to the supply wire’s maximum amperage rating. However, these models can draw significantly higher surge currents for brief periods when the ac line voltage is initially applied. After all mechanical assembly is completed, connect the two output leads of the external 5A CT to each other after they are run through L1’s center hole. Pressure-style connectors (commonly referred to as “wire nuts”) are acceptable as long as they are rated for the number of conductors and voltage involved. 4. AC Supply Polarity and Grounding: The two supply inputs, TB1-A and TB1-B, on ACA5-20RM ammeters are not in themselves polarity sensitive, that is, they have no internal “AC LO” or “AC HI” designations. ACA5-20RM ammeters do not include or require a connection to earth/ chassis ground. 9. Replacing Analog Panel Meters: ACA5-20RM ammeters can be used as direct replacements for most analog panel meters driven by external 5A CT’s. All wiring operations must be performed with both the load and the supply power sources completely de-energized. 5. Connector Torque Ratings: It is important to tighten TB1’s, screw-terminals to their rated torque specification of 3.6 pound-inches (0.4Nm). Proper tightening will minimize connector losses and ensure safe, reliable operation. BACK VIEW A FUSED AC POWER TB1 B L1 Figure 2. Typical wiring diagram www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_ACA5-20RM.A01 Page 3 of 5 ACA5-20RM Series True-rms-AC Ammeters with 5A CT Inputs PANEL INSTALLATION All connections to ACA-20RM Series ammeters must be made after the ammeter 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. plastic standoffs over the bezel’s threaded studs. Install the ACA5-20RM pc-board assembly as shown and 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. Care should be exercised when passing conductors through the ammeter’s built-in toroid sensor L1. The installed wire-positions should be such that minimal mechanical forces are applied to L1, TB1, or to the ammeter itself. In high-vibration environments, it is strongly recommended that adequate strain reliefs be used for all wiring. 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 or modifications. Using Figure 3 as a guide, carefully insert the bezel/color filter assembly into the panel opening. From the rear of the panel, install the four round PANEL 0.032 (0.8) Thick Gasket Standoff Gasket Nut Standoff 0.190 (4.83) Board-Cutout Bezel ACA5-20RM AC Ammeter SIDE VIEW Figure 3. 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_ACA5-20RM.A01 Page 4 of 5 ACA5-20RM Series True-rms-AC Ammeters with 5A CT Inputs MECHANICAL SPECIFICATIONS FRONT VIEW 2.100 (53.34) 100-10 M9 100-10 M9 1.400 (35.56) BACK VIEW A CAL B TB1 Lead Length 2.0 (50.5) min. 0.35 (8.9) Diameter SIDE VIEW 0.250 (6.35) 0.480 (12.19) MECHANICAL DIMENSIONS: Inches (mm) TOLERANCES: 2 PL DEC ±0.02 (±0.51) 3 PL DEC ±0.010 (±0.254) 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 01/27/09 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_ACA5-20RM.A01 Page 5 of 5