Variable Speed Drive (VSD)
Pre-Commissioning checks for VSD -
1.Power and motor cables are correct- Size and termination 2.Power cable shields correctly earthed to PE terminal 3.No faults on the cables prior to energize the VSD - Megger 4.Controls cable correctly installed and terminated 5.Control cable shield correctly earthed at one end only. 6.Check cooling fan connection and conform that correct voltage tap is selected on the auxiliary transformer
Commissioning of VSD
When pre commissioning complete - Ready for energizing VSD.
1.First Disconnect the motor cable.This will avoid unexpected motor starts.Turn on the power.
2.Check all basic electrical parameter
-Measure the power supply voltage -Measure the DC bus voltage -Conform the microprocessor has completed test sequence -Confirm that control system is “READY” -Confirm cooling fan is running (Make sure direction is correct)
3.Record test and settings in “Commissioning test report”
Basic Setting Parameters of VSD
Before VSD connected to mechanical load basic parameters must be correctly set.
Base Voltage - Selected for motor rated voltage -Ensure correct output Voltz/Hz ratio to motor
Base Frequency - Selected for motor rated frequency
Maximum Speed - Usually set to 50 Hz or higher
Minimum Speed - Usually 0 Hz for a pump or fan drive and higher for constant torque applications.
Rated motor current
Acceleration Time - determine the Ramp-up time
Deceleration time - determine the ramp-down time