HYDRAULISCHER ANTRIEB FUER EIN ELEKTRISCHES SCHALTGERAET

The hydraulic drive device is provided for operating the contact arrangement (1) of electrical switchgear. It has an operating cylinder (4) and a differential piston (5) which is guided in the operating cylinder (4) and acts on the contact arrangement (1), and a hydraulic fluid reservoir (8) for the rapid operation of the differential piston (5) and hence of the contact arrangement (1) when carrying out a switching command occurring on the switch gear. This hydraulic drive device is intended to be characterised by simple, robust construction and at the same time is intended to ensure good availability of the electrical switch gear which it drives. This is achieved by the hydraulic fluid reservoir (8) having a virtually constant storage capacity which is filled with a comparatively easily compressible hydraulic fluid.