4861 Standard Electronic Voltage Divider Unit

HAEFELY / Tettex

The 4861 series (control unit and capacitive HV divider with 3370 compressed gas capacitor and 3320 air capacitors) high precision standard voltage divider is used as a variable comparison standard in the differential method (bridge) measurement of high voltage instrument transformers. The special active guard controlled design of this divider allow the highest accuracy results. This standard voltage divider is ideal for integration with the 2767 Automatic Instrument Transformer Test Set or 2769 Automatic Voltage Transformer Test Set in a full remote controlled instrument voltage transformer test system.

The high voltage divider unit is a capacitive high voltage divider (compressed gas standard capacitor C1 and air capacitor C2) and an electronic device in series, constituting a variable electronic divider. Capacitive voltage divider C1/C2 divides the primary voltage U_prim to voltage U1, which the electronic device matches to the required secondary voltage U_sec. Voltage instrument transformers of less than 1 kV primary voltage can be connected directly to the electronic system via the adapter box supplied with the divider.

The main components of the electronic device are an input amplifier and a guard-potential control (up to 1010 V), an electronic divider and a power amplifier with the output stage. The instrument is protected against setting errors, over voltages, and short-circuits. Error messages are indicated on the dot matrix display.