Circuit arrangement for the actuation of an electric-motor drive, in particular a pump drive, in a large domestic appliance

Abstract

In order to be able to operate variably and in particular in an optimised manner in a large domestic appliance not only the main drive (17) thereof but also the auxiliary drive (24) thereof, without having to substantially increase the overall control complication and expenditure of the appliance required for that purpose, the main and auxiliary drives (17, 24) are fed from the same dc voltage intermediate circuit (19) which is provided only once, by way of change-over switch sets (12), by half-bridge circuits (21, 21′). For that purpose it can be provided that the frequency converter (15) with its bridge circuit (21) for the main drive (17) is switched over in single-pole or multipole mode to the rotary field motor (23, 25) of the auxiliary drive (24) by way of a change-over switch set (12) connected in its output-side motor lines (13); or in the frequency converter (15) two half-bridge circuits (21, 21′) which are associated with the main and the auxiliary drives (17, 24) are operated in parallel from the dc voltage intermediate circuit (19). Such alternative circuit configurations, with the frequency converter (15) which in itself is designed for the main drive (17), by way of control of the rotary speed or the direction of rotation of the auxiliary drive (24), permit the implementation of additional flow-dependent functions such as for example flushing a washing machine pump free of washing threads and fibres caught therein.

Dependencies are inferred from the claim text.