System Composition The ES9000P/Q synchronous undisturbed switching soft start MVVFD's composition is similar to that of the ES9000A/S, just with a simple software upgrade. This machine integrates a number of equipment, including the reactor, switch over cabinet, inspection and control systems for synchronous switching to a basic MVVFD in order to form a complete synchronous switching soft start MVVFD system.
The system contains the following components 1. ES9000 A/S MVVFD 2. CMK-TQ series synchronous undisturbed switching control board 3. GTA2-II series high voltage reactor cabinet 4. CMK-PLG-AQ series synchronous inspection and switch-over control system 5. CMK-GP series power frequency switch-over cabinet
Working Principle In a one drive, one synchronous undisturbed switching soft start MVVFD, when the motor starts, and the output disconnector and the circuit breaker are both closed, the MVVFD begins its driving process for the motor. The output frequency increases from 0-50Hz, with a duration that customers can easily set. The output voltage will also increase from 0 to 6/10 kV. The motor then begins to operate at a rated rotational speed.
After the output frequency reaches 50Hz and the grid integration command is received, the MVVFD adjusts the output voltage to the same level as the input voltage on the grid. After the system detects that the frequency, phase and amplitude of the output voltage of the MVVFD and the input voltage of the grid are the same, the circuit breaker on the motor frequency power will close. At this time, the motor is then powered by both the MVFFD and the grid, and the current is transferred to the grid through the MVVFD. The system then disconnects from KM2, and the motor is then fully powered by the grid. By now, motor startup has completed. The contactor KM1 is disconnected, and the MVVFD will stop working.
Features 1. Precision inspection system 2. Synchronous control and intelligent synchronous point decision algorithm 3. Soft start of motor, start-up current smaller than rated current 4. Undisturbed switching with a transfer current less than the rated current 5. Unlimited start-up times 6. Low requirements on grid; powered by either mains, captive power generation plant, or diesel engine; adaptive to applications with large loads and small grid automatic operation, low maintenance requirements 7. One for multiple (one-drive-one, one-drive-two, one-drive-multiple) 8. Multi-frequency mutual backup (two-drive-two, two-drive-three) 9. Securest and most reliable undisturbed switching in industry
Applications 1. Soft-start variable frequency drive for high-power fans 2. Soft-start variable frequency drive for high-power air compressors 3. Small-current soft starter for fans and air compressors powered by power generators 4. Dual-frequency mutual backup of two-drive-two operation for key process equipment (two-drive-two variable frequency operation for main sintering fans) 5. Other applications requiring variable-frequency soft start and synchronous undisturbed switching
