METHOD FOR RELIABLE CONTROL OF COMMON VARIABLE FREQUENCY ELECTRIC DRIVE Russian patent published in 2012 - IPC H02P1/54 H02P1/56 H02H7/09 H02H7/122 

FIELD: electricity.

SUBSTANCE: frequency converter (FC) (1) accelerates the electric motor (6) and ensures its operation at a frequency other than the mains frequency. In these modes the commutators (2) and (4) are (5), (8) are (9) are open. After the motor (6) acceleration and during its operation at a fixed mains frequency the commutator (8) while the commutator (4) is tripped with the FC (1) out of operation. The motor (7) is out of operation and in the backup preparedness condition. In case of breakdowns in the motor (6) the controller (10) puts the backup motor (7) into operation. In case of the FC (1) internal breakdowns and faults the controller (10) switches the installation to the relay control mode with power supply from the mains. In case of the breakdown object unrevealed (unclassified failure) the controller (10) locks the FC (1), disconnecting it from the commutator 4 and the motor (6). For a short period of time the FC (1) is actuated to run idle. The breakdown recurrence means its localisation within the FC (1) which becomes tripped. The whole installation is switched to the relay mode with the motor (6) connected to the mains (3) through the controller (10) affecting the commutator (8). If in the process of the FC (1) idle run testing the breakdown fails to recur, the controller (10) concludes malfunction of the motor (6) and puts the motor (7) including the commutator (5) into operation from the FC (1).

EFFECT: improving reliability.

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