New Development – Variable-Resistance Transducer for Vacuum Circuit Breakers

According to the scope of testing and test code for the high-voltage circuit breakers the following three parameter groups shall be monitored:

  • Time (switch on/off time by each pole, full time of crosshead travel, time difference, delay in contact closing/opening, dead time etc.);
  • Velocity (crosshead rate during switching on/off or at a given distance from these points, the maximum velocity);
  • Travel (travel till switching on, pressing force and full travel).

The process of recording time characteristics for any type of high-voltage circuit breakers is quite simple, on the other hand to obtain the velocity and travel characteristics the special circuit breakers are required.

That is why SKB EP had developed linear and angular movement transducers, which proved to be highly accurate and easy-to-use.

In most cases, travel of the circuit breaker moving part is measured by linear movement transducer DP12, which consists of a measuring rod with a scale and cylindrical shaped housing. Though, in some types of circuit breakers the moving parts are not available for use of DP12 transducer (series of circuit breakers: VMT, VM, VT and VK), in these cases angular movement transducer DP21 is used. At that, angular to linear motion conversion formula is incorporated into PKV/M7, PKV/U3.1 and PKV/U3.0 instruments which are equipped with transducers.

Linear (DP12) and angular (DP21) movement transducers made by SKB EP

SKB EP keeps up with the times and produces completing units of instruments according to users’ requests. Therefore, for ease of measuring on vacuum circuit breakers with an open insulating housing and access to the moving contact of arc chute the DP32.1 variable-resistance transducer with analog channel was designed to measure linear displacement in the range of 25 mm.

Vacuum circuit breaker with an open insulating housing

DP32.1 transducer consists of a cylindrical shaped housing, where special elements with retractable actuating rod are located. The rod can freely move inside the sensing element along the axis thereof. DP32.1 transducer is recommended to complete control instruments of high-voltage circuit breakers PKV/M7, PKV/U3.1 and PKV/U3.0

DP32.1 transducer is attached to the moving part of the circuit breaker using some special attachment devices:

Use of this development dramatically simplifies installation and reduces the impact on the measurement process, thereby providing better fault diagnostics. If you are interested in new DP32.1 transducer, you can always contact our managers to get the answers you need: e-mail: or tel.: +7 (3952) 719-148.

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