5-3
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5.1.1 Soft Charge and Rectifier Circuits Test:
D-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
drive. 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 making the test, it is necessary to ensure the soft
charge fuses, F1, F2, and F3, located on the soft charge card,
are good.
Figure 5-2 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.
5.1.1.1 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.
NOTE
If unit has fused disconnect option, make test
connections L1, L2, and L3 to output (drive) side
of disconnect. Do not unplug connector.
1. Measure fuse F1 from mains input L1 (R) to
MK106 pin 10 on power card.
2. Measure fuse F2 from mains input L2 (S) to
MK106 pin 8 on power card.
3. Measure fuse F3 from mains input L3 (T) to
MK106 pin 6 on 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 6.
Figure 5-2. Soft Charge Card Fuses
Fuses F1, F2, F3
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