After Repair Tests - GE AF-650 GP Operating Instructions Manual

4.7 After Repair Tests

Following any repair to a frequency converter or testing of a frequency converter suspected of being faulty, the following procedure must be followed to ensure
that all circuitry in the frequency converter is functioning properly before putting the unit into operation.
1. Perform visual inspection procedures as described in the table Visual Inspection.
2. Perform static test on the drive as described in Static Test Procedures.
3. Remove the three output motor bus bars from each inverter module.
4. Connect a 610 – 800 VDC power supply to the switch mode power supply (SMPS) input to each module using the test cable 6KAF6H8766.
4
5. Apply power to the SMPS and observe that the display lights up properly. (The fans will not operate when powered in this manner.)
6. Give the frequency converter a run command (press Hand) and slowly increase the reference (speed command) to approximately 40 Hz.
7. Using the Signal Test Board 6KAF6H8437 and an oscilloscope, check the waveform at pins 25 - 30 with the scope referenced to pin 4. This procedure
must be performed on each inverter module. Each waveform should approximate the illustration below.
8. Connect a 24 VDC power supply to the DC bus of the drive. This can be done on the DC bus output of the rectifier module or the bus bars connecting to
the top side of the DC fuses on any of the inverter modules.
9. Observe the phase to phase waveform on the output bus bars of each phase of each inverter module. This waveform should appear the same as the
normal output waveform of a properly operating drive, except that the amplitude will be 24 V instead of the full output voltage of a normal drive.
10. Press the OFF key of the frequency converter, disconnect power from both power supplies, and reinstall jumper connectors to the SMPS input plugs on
all modules.
11. Reinstall the motor output bus bars on all inverter modules.
12. Apply AC power to the drive.
13. Apply a start command to the drive. Adjust the speed to a nominal level. Observe that the motor is running properly
14. Using a clamp-on style current meter, measure the output current on each phase. All currents should be balanced.
Illustration 4.1: After repair waveform: 2v/div 100us/div run at 10 Hz
60
High Power Service Manual for Unit Sizes 6x