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Instrument Transformers Specifications

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General Specifications




   Transformer Category       
   Your choices are...
 
      
 
   Current Transformer
 
     Current transformers are used to step down current in a very predictable fashion with respect to current and phase. They are generally used as inputs to current instruments.
 
   Voltage / Potential Transformer
 
     Voltage transformers can be defined as transformers in which the secondary voltage is substantially proportional to the primary voltage and differs in phase from it by an angle that is approximately zero for an appropriate direction of the connections. Potential transformers are designed for monitoring single-phase and three-phase power line voltages in power metering applications. They are used primarily in a step down environment to monitor voltage. They can be used for line-to-line or line-to-neutral connections in the same manner as ordinary voltmeters. The secondary voltage bears a fixed relation with the primary voltage so that any change in potential in the primary circuit will be accurately reflected in the meters or other devices connected across the secondary terminals. Potential transformers can be used with voltmeters for voltage measurements or they can be used in combination with current transformers for wattmeter or watt-hour meter measurements. They are used also to operate protective relays and devices, and for many other applications. Since they are used in a monitoring capacity, they generally require much greater accuracy in design. Potential or voltage transformers are also used to provide accurate voltages for meters used for billing industrial customers or utility companies.
 
   Other
 
     Other unlisted transformer types.
 
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   Type / Applications       
   Your choices are...
 
      
 
   Commercial
 
     The commercial class transformers are well suited for low power current monitoring applications.
 
   ANSI Class
 
     The ANSI metering class transformers are units intended for power monitoring applications where high accuracy and minimum phase angle error are required.
 
   Multi-ratio
 
     These transformers have several outputs.  Each output corresponds to a different transformer ratio.
 
   Three-phase
 
     The transformer is used in three-phase systems to measure current or voltage.
 
   Split Core
 
     Split core current transformers are designed to provide a low cost method to monitoring electrical current. A unique hinge and locking snap allows attachment without interrupting the current-carrying wire.
 
   Toroidal / Window
 
     Toroidal or donut transformers have no internal primary winding as such. The primary is the conductor in which the current is to be monitored, and is not an integral part of the transformer. The primary conductor is simply placed through the window of the current transformer. The core in this type is a band of magnetic grade steel concentrically wound upon it. This is an extremely efficient core design that has no breaks or gaps in the magnetic path. While other types of core designs may produce relative high levels of audible noise, (approximately 30-70 DB's) the toroidal core rarely produces an audible noise level.
 
   Wound Primary
 
     Wound primary current transformers have primary windings that usually consist of more that one turn.  Wound primary transformers have an internal primary winding and have no windows for the primary conductor to pass through. They have an advantage in that the designer can make units with low current ratios that therefore have better accuracy and burden capabilities. The primary of the transformer is inserted in series with the conductor that is being monitored. For this reason there is some hesitation to use wound primary transformers even though they may be the most effective way to achieve the desired performance, especially for the low current ratio requirements. The wound primary types may be designed using the toroidal cores because of its excellent efficiency. The wound primary type is more common in the higher (greater than 600V class) voltage class current transformers as it makes the problems of the higher voltages easier for the design engineer to cope with, while keeping the design as cost effective as possible.
 
   Bar
 
     Bar current transformers are toroidal transformers with a bus bar permanently inserted through the window of the toroid. The bus bar serves as the primary conductor. Bar transformers are inserted directly into the circuit that they will be used to monitor. It is a common error to refer to wound primary transformers as bar transformers because the primary connections are made to bus bars. In the wound type, bus bars are a means of connection and not continuous bars
 
   PC Mount
 
     PC mount transformers offer a small footprint for the design engineer looking to measure sensor current or voltage on a computer board. Some applications for which these transformers are used include sensing current overload, ground fault detection, metering, isolated current feed-back signal in switch mode power supplies, motor current load / overload, lighting, switch controls, ultra-sound current, high resolution sonar current and isolated bi-directional current sensor with full wave bridge.
 
   Under / Over Current Sensing
 
     Transformer used to measure under and/or over current.
 
   Noncontact Device
 
     Noncontact current transformers can accurately measure current waveforms without coming into electrical contact with the circuit.
 
   Other
 
     Other unlisted types / applications.
 
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Features




   Waterproof
 
     The transformer has a waterproof case.
 
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   Military Standard
 
     The transformer satisfies military standards or specifications (MIL-SPEC).
 
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   Meets ANSI C12 Standards
 
     ANSI standards for electric metering.
 
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   Meets IEC 1036 Standards
 
     IEC electrical metering standards.
 
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   Outdoor Use
 
     The transformer can be used outdoors.
 
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