Instrument Current transformers shown below are installed around a power line to measure current in power distribution systems. The Instrument Current Transformers are available in a removable bar split core style or solid core style. The split core instrument current transformer and the solid core instrument current transformer will provide an accurate current ratio and phase relationship to enable accurate secondary connected metering. Generally they are also referred to as current transformers (CTs), instrument transformers, split core current transformers, solid core current transformers. The Sentran Corporation CTs are typically described by its current ratio from primary to secondary. A 1000:5 CT will provide an output current of 5 amperes when 1000 amperes are flowing through its primary winding. Standard secondary current ratings are 5 amperes or 1 ampere, compatible with standard measuring instruments.
Burden and accuracy are usually stated as a combined parameter due to being dependent on each other. Metering style CTs are designed with smaller cores and VA capacities. This causes metering CTs to saturate at lower secondary voltages saving sensitive connected metering devices from damaging large fault currents in the event of a primary electrical fault. A CT with a rating of 0.3B0.6 would indicate with up to 0.6 ohms of secondary burden the secondary current will be within a 0.3 percent error parallelogram on an accuracy diagram incorporating both phase angle and ratio errors.
Model 5ASC solid-core current transformers
Model 5ASMV medium voltage split-core current transformers
Model SUM Summation Current Transformer
Model AUX Auxiliary Current Transformer
Model 5ASZ Zero Sequence Balance Current Transformer
Model 5ARP Relay Protection Current Transformer
Model 5AST Multi-tap or Multi-ratio Current Transformer