DMS Accessories 5 Amp AC Current Transformers Order online at www.datel.com These commercial grade, UL & CSA recognized, donut with DATELs ACA5 series ammeters). However, any CT can generate style AC current-transformers (CT) provide an isolated 0-5A potentially lethal voltages if its output current is suddenly interrupted. output that can be used with DATELs ACA5 Series of digital For example, loose secondary connections can produce a condition ammeters. Installation is straightforward: simply pass the load- referred to as inductive kick. Inductive kick can generate extremely carrying conductor through the 5A CTs primary window, and high voltages across the open secondary connections. then route its secondarys leads through the ACA5-ammeters Therefore, all connections made to a CTs secondary leads must only built-in, low-burden, toroid sensor. be performed with zero current flowing in the primary circuit. Never All models feature rugged, fully insulated construction, allow- operate a CT with its secondary circuit open and current flowing in ing continuous operation with primary voltages up to 600Vac, the primary. at line frequencies from 50 to 400Hz. Fourteen models are available to enable accurate measurements from 50A through 2. CT Connections and Grounding: Some applications require con- 2000A. When combined with DATELs ACA5 Series ammeters, necting one of the CTs 5A output terminals to earth/chassis ground. secondary lead-extensions may be used for those applications In the USA, consult the latest revision of the National Electrical Code where the CT cannot be installed in the immediate vicinity of for more information. the ammeter. After all mechanical assembly is completed, pass the 5A secondary leads through the ACA5 ammeters built-in toroid, then connect the General Specifications (All models) two leads together as shown in Figure 1. For this connection, and Insulation Class 600V, 10kV BIL full wave for connections involving lead extensions, pressure-style connectors Frequency Range 50-400Hz (commonly called wire nuts) are acceptable as long as they are rated Supplied Secondary Leads Flexible conductors, 24 (61cm) for the currents and voltages involved. 2 16AWG (1.8mm ), UL Style 1015, 105C 3. Installation: CTs must be installed in a manner that ensures no Max. Secondary Lead Length See Table 1 and technical note 5 excessive stresses are applied to the primary conductor that passes Rated Accuracy See Table 1 and technical note 6 through the CT or to the secondary circuit and its associated instru- Burden See Table 1 ments. Use plastic tie-wraps and/or other suitable non-conductive UL FIle No. E93779 restraining devices to secure the CT. CSA File No. LR89403 Weight 1.0 lbs. (454g) AC POWER SUPPLY Basic Lightning Impulse Insulation Level (BIL): The insulation strength refer- enced to the crest value of an impulse voltage-waveform which rises to a crest ACA5-20PC-X-ACX value in 1.2 microseconds, then drops to 12 the crest value in 50 microseconds. A B TB1 Tehnical Notes TO AC LOAD IMPORTANT To ensure safe and reliable operation, Current Trans- L1 formers and associated equipment must be installed and serviced 5A CURRENT by qualified technical personnel. Never open the CTs secondary TRANSFORMER connections while the primary is energized. Open CT secondary (see technical notes) wiring can generate potentially lethal voltages when the primary circuit is energized. Contact DATEL if you have any doubts 0-5A regarding the installation or operation of any of our ac-mains OUTPUT measurement instruments and accessories. 1. CT Precautions: In normal operation, a 5A current transformers Figure 1. Typical Connections secondary circuit operates at a relatively low voltage due to its closed- loop, low burden configuration (essentially zero Ohms when used DATEL, Inc., Mansfield, MA 02048 ( USA) Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 Email: sales datel.com Internet: www.datel.comDMS Accessories 5 A M P A C C U R R E N T T R A N S F O R M E R S 4. Reference Documentation: Prior to connecting CTs to any measure- burden column. Accuracy measurements are taken at 100% primary ment device (analog or digital), relay, or other apparatus, be sure to current, using a resistive burden and a nominal line frequency of 60Hz. thoroughly review the applicable devices technical documentation (for 7. Polarity: CTs are marked with H1 (primary) and X1 (secondary) example, DATELs ACA5-20PC product data sheet). In particular, make polarity indicators. When a CTs only function is to measure amperes, sure the CTs ratings meet the requirements of your application. polarity markings can be disregarded. However, correct polarity is 5. Secondary Lead Extensions: When calculating the total burden mandatory in applications in which the phase relationship between imposed on a CTs 5A output, DATELs ACA5 digital ammeters input two currents is involved (watt or watt-hour meters are two examples impedance is negligible and can be assumed to be zero Ohms. In of polarity sensitive applications). Refer to the respective instruments many applications, the length of secondary wiring can be increased documentation for more information. up to the value specified in Table 1 without adversely affecting perfor- 8. Thermal Rating Factor: The thermal rating factor denotes the amount mance. by which the primary current can be increased on a continuous In order to achieve the specified accuracy, the maximum permissible basis over its rated value without exceeding the CTs maximum tem- burden must not exceed the value shown in Table 1. When used with perature rise. ACA5 ammeters, the total burden is the sum of the resistance of the The formula below can be used to calculate thermal rating factors at CTs 24 leads and any lead-extensions. Make sure all connections are temperatures above 30C. securely tightened and properly strain relieved. If terminal blocks are 2 (85 - NAT)(RF) used for intermediary connections, refer to the manufacturers torque NRF = recommendations. NAT Table 1 lists general guidelines for adding lead extensions when using NRF = Rating Factor at New Ambient Temperature DATELs ACA5-Series ammeters as the readout device. The lengths in RF = 30C Rating Factor Table 1 assume the lead extensions are 16AWG. Stated dimensions NAT = New Ambient Temperature are one-way distances between the ACA5 and the CT. Make sure all secondary extensions meet or exceed the specifications of the Example: Find the 55C. thermal rating factor of a 2000:5 CT whose CTs built-in leads. In order to minimize external noise pick up, lead 30C rating factor is 2.0 extensions should be as kept short as possible. 2 (85 - 55)(2) = 1.48 6. Accuracy: The indicated accuracy specifications are valid as long as NRF = 55 the total secondary burden does not exceed the value in Table 1s Table 1. Selection Guide DATEL Part No. Current Ratio Accuracy Burden Lead Ext. Thermal Rating Factor (Amps) ( 60Hz) VA (Ohms) Feet (Meters) ( 30C) 39-3681401 50:5 2% 1.5 (0.06) 4 (1.2) 1.5 39-3681402 75:5 2% 3.0 (0.12) 10 (3.0) 1.5 39-3681403 100:5 1% 3.0 (0.12) 10 (3.0) 1.5 39-3681404 150:5 1% 6.0 (0.24) 20 (6.1) 1.5 39-3681405 200:5 1% 8.0 (0.32) 30 (9.1) 1.5 39-3681406 250:5 1% 10.0 (0.40) 40 (12.2) 1.5 39-3681407 300:5 1% 12.5 (0.50) 50 (15.2) 1.5 39-3681408 400:5 1% 12.5 (0.50) 50 (15.2) 1.5 39-3681409 500:5 1% 20.0 (0.80) 80 (24.4) 1.5 39-3681410 600:5 1% 10.0 (0.40) 40 (12.2) 2.0 39-3681411 750:5 1% 10.0 (0.40) 40 (12.2) 2.0 39-3681412 1000:5 1% 10.0 (0.40) 40 (12.2) 2.0 39-3681413 1500:5 1% 12.5 (0.50) 50 (15.2) 2.0 39-3681414 2000:5 1% 15.0 (0.60) 60 (18.3) 2.0 Underlined digit(s) of part number corresponds to the matching ACA5 ammeter. For example, part number 39-3681403 is used with an ACA5-20PC-3 ammeter to measure currents up to 100.0A. DATEL, Inc., Mansfield, MA 02048 ( USA) Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 Email: sales datel.com Internet: www.datel.com 2