ASYNCHRONOUS ELECTRIC DRIVE Russian patent published in 1994 - IPC

FIELD: electric drives of continuous action, for instance, of escalators, conveyers, cable railroads and so on. SUBSTANCE: asynchronous electric drive has three-phase asynchronous electric motor 1, three-phase voltage transformer 2 which secondary winding is connected between network and winding of stator of electric motor 1 and which primary winding is linked to output of inverter 4 fitted with control unit 5. Its input is coupled to output of uncontrolled rectifier 3. Input of rectifier is meant for connection to three phases of network into one of which primary winding of single-phase current transformer 7 is placed. Primary winding of single-phase voltage transformer 6 is connected to two other phases. Secondary winding of the latter is connected with its start and finish to first and second inputs of pickup 8 of reactive current of network, third and fourth inputs of which are coupled correspondingly to start and finish of secondary winding of single-phase current transformer 7 and output of pickup is linked to input of unit 5 of control over inverter 4. EFFECT: simplified design, improved energy characteristics thanks to increase of accuracy of full compensation of reactive power. 1 dwg