Differential adjustment equipment

Guaranteed safety test - simple and effective

The differential tripping part of a mechanical RCB is the internal relay. This part is adjusted by a electromagnetic field. Those aircoils can be use in single constellation or in Helmholz configuration (double coil). One adjustment cycle is started with a saturation shot. This should saturize the internal ferrit. Directly after this saturation, the ferrit will be adjusted by a decreasing sinus field.

The device is armed and tripped. The second tripping is measured. This value will be used to calculate the next adjustment value. The tripping current is graphically shown corresponding to the adjustment value. This graphic shows the behavior of the device.

When the device trips in the tolerance area, the adjustment is stopped and the tests can start. They can be done in the same station or in a following station.

For the quality of adjustment there are following factors important:

  • a low magnetic field frequency (should be about 50 Hz)
  • a very reproduceable adjusting field level
  • a slow decreasing value