GE Industrial Solutions AF-600 FP High Power (460V_575V 150HP and above) - Manual (Page 74)

6.2.1 Soft Charge and Rectifier Circuits Test: 4x-frame size
Both the rectifier and soft charge circuits are tested simultaneously. The soft charge circuit is made up of the soft charge rectifier, fuses and the soft charge
resistor. The rectifier circuit is made up of the SCR/diode modules. The soft charge resistor limits the inrush current when power is applied to the frequency
converter. The soft charge circuit card also provides snubbing for the SCRs.
It is important to pay close attention to the polarity of the meter leads to ensure identification of a faulty component should an incorrect reading appear.
Prior to performing the test, it is necessary to ensure the soft charge fuses, F1, F2, and F3, located on the soft charge card, are good.
Illustration 6-4 shows the soft charge card and the location of the fuses. It is for reference only. It is not necessary to remove the card to perform the tests.
Soft charge fuse test
Use a digital ohmmeter to test continuity on rectifier fuses F1, F2, and F3 at connector MK106 on the power card.
NB!
If the unit has fused disconnect option, make test connections L1, L2, and L3 to the output (drive) side of the disconnect. Do not unplug the connector.
1. Measure fuse F1 from the mains input L1 (R) to MK106 pin 10 on the power card.
2. Measure fuse F2 from the mains input L2 (S) to MK106 pin 8 on the power card.
3. Measure fuse F3 from the mains input L3 (T) to MK106 pin 6 on the power card.
A measurement of 0 ohms indicates good continuity. Replace any open fuse (infinite resistance).
To replace a soft charge fuse, follow the soft charge disassembly instructions in Section 7.
130BX65.12
F1, F2, F3
Illustration 6.6: Soft Charge Card Fuses
380–480V: Blue MOV & 8 PTCs 525–690V: Red MOV & 6 PTCs.
AF-650 GP and AF-600 FP High Power Service Manual
73
6