I have a YVAA that has a DC Bus voltage imbalance message and traced the problem to a faulty bleed resistor. After discharging the bus with the York discharge tool , I was able to get the machine to run, and while running I observed the voltages on both sides of the bus. The difference between the two was about 60vdc. Is this normal? Also, has anyone ever replaced a capacitor in one of these drives? We have a lot of power problems at this location and I would like to keep some on hand if this is an item that is commonly replaced.
wlammey
The VFD troubleshooting manual is quite clear that you do not replace individual caps in the DC bus, you replace the entire assembly. Individual ones, like the film caps across the IGBTs, and the snubbers, can be replaced individually.
Sounds like you have the right manual, it’s not as specific as maybe I made it out to be.
In the procedures, you are checking for shorted or open caps in the bus, but you don’t disconnect the bus and identify which. It just says that if either of those tests is NG, then to replace the assembly.
Anyway, you can get that manual from the JCI website under chiller knowledge exchange
In the procedures, you are checking for shorted or open caps in the bus, but you don’t disconnect the bus and identify which. It just says that if either of those tests is NG, then to replace the assembly.
Anyway, you can get that manual from the JCI website under chiller knowledge exchange
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