Voltage Transformers (Potential Transformers) as Circuit Breaker Operation Power Source
EPF-3SF1, EPF-6SF2
Voltage transformers EPF-3SF1 and EPF-6SF2 are medium-voltage, indoor-type potential transformers cast in epoxy resin, commonly installed on switchgear (3.3kV or 6.6kV) to serve as an auxiliary power source* for circuit breaker operation. Positioned atop the switch as an operational power source, these transformers can handle relatively high outputs for short durations. Featuring Class-F heat-resistant insulation material for the coils, each voltage transformer is equipped with two power fuses on the primary side to safeguard against overload and short-circuit currents.
* Auxiliary power source: In this application, the voltage transformer may also be referred to as a "control power transformer" (CPT), "control transformer" (CTR), "industrial control transformer," or a "machine tool transformer."
Medium-Voltage Epoxy-Cast Indoor PTs
About the Product
Voltage transformers (potential transformers) EPF-3SF1 and EPF-6SF2 are primarily mounted on switchgear (3.3 kV and 6.6 kV, respectively) as an auxiliary power source for circuit breaker operation. Compact and of a flatter shape than other models, these voltage transformers are mounted on top of the power switch as an operation power source and are compatible with short-interval large output. With Araldite® epoxy resin as insulation, these voltage transformers also feature a Class-F heat-resistant insulation material for the coils. Two fuses on the primary side offer protection against overload and short circuit currents. EPF-3SF1 and EPF-6SF2 voltage transformers are characterized by a high-quality exterior, excellent moisture resistance, and superior electrical performance.
Specifications
Other standards and specifications available.
| Model | Standard | Phase (Φ) | Frequency (Hz) | Primary Voltage (V) | Secondary Voltage (V) | Burden / Accuracy | AC/BIL （kV） | Primary-Side Fuses | Approx. Weight (kg) |
| EPF-3SF1 | IEC | 1 | 50 or 60 | 3600 3450 3300 | 120 115 110 | 100VA / 1.0CL 200VA / 3.0CL | 10/40 | 2 | 8.5 |
| EPF-6SF2 | IEC | 1 | 50 or 60 | 7200 6600 4200 | 120 115 110 | 200VA / 1.0CL 500VA / 3.0CL | 20/60 | 2 | 16 |
| 3600 3300 | 10/40 | ||||||||
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【Product Brochure】Voltage Transformers (Circuit Breaker Operation Power Source), Models: EPF-3SF1/6SF2
Easy-to-print document, containing product description and specifications.
【Product Dimensions】Voltage Transformers (Circuit Breaker Operation Power Source), Models: EPF-3SF1/6SF2
Download PDF for basic drawing(s) and dimensions of this product. For more detailed information, please contact CIC.
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CT & PT Selection Guide: How to Choose a Current Transformer or Potential Transformer
How to select, based on application and power system attributes, the primary and secondary currents, burden, accuracy, rated frequency, type (indoor vs. outdoor), insulation material, etc.
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