Leaving ABB VFDs off

Saturn_Europa

Saturn_Europa

Senior Member
Location
Fishing Industry
Occupation
Electrician Limited License NC, QMED Electrician
I work on a large fishing boat. There are 3 very expensive ABB VFDs that run deck winches. We’ve seen ground fault failures with the VFDs during ship yard maintenance. During this time, the VFDs are not in use and but are powered on. The main switch board had a ground fault and we traced the fault back to the ABB VFDs. The only solution was to replace the VFDs.

Is it better to turn off the power to the VFDs if we’re not going to be using them for a few months?

During ship yard maintenance there’s lots of welding and blackouts when switching from shore power to generator.

The only downside I can see to leaving the VFDs powered down is possibly condensation accumulation.
 
herding_cats said:
YASKAWA dealer here:

Absolutely shut them down. Put a trash bag around them. They need to be off when switching from shore to generator.
Click to expand...
Yes, not just off, but breaker/disconnect open!

From experience, in a lot of shore power situations, they connect to an ungrounded delta system, or they have a bad neutral connection, which can cause damage in the front-end of the drive if there is any kind of ground fault anywhere. The drive has a grounding jumper that can be removed, but then it has to be put back on again when done, so it’s a PITA. If you just disconnect the line from the drive, it’s no worries.
 
Not a fan of ABB because they always gave me the run around. Anyway we had about a dozen Danfoss 40 to 75 HP drives on a roof. They came from the factory with a thermostat & heater to control humidity. Heater could only turn on while the drives were off. I was thinking about installing a humidity switch in parallel with heater thermostat. In the over ten years drives ran had a lot of false what Danfoss called " Earth faults " for a few years until I asked our Danfoss service tech about it. Here a ribbon cable to the control board was causing the problem and was covered by an extended warranty. Like others posted would power down the drives when not needed.You might want to install a 120 volt strip heater inside of drive panels if room permits to control humidity and keep panel from rusting. A contact could be installed on the HOA ( hand off auto ) selector switch if one is provided to only supply power to humidity control while drives are off. We had 100 to 150 HP ABB & Danfoss drives that powered chiller pumps so did not run in the winter. Danfoss had a thermostat for the door fans so they only ran when interior of cabinet got over above 90 degrees. ABB fans ran 24/7 pulling in dirty air so we had to blow out fan filters once a month when drives were off. When I questioned ABB if they had a hidden thermostat or other type of control they want to know why I was asking. Engineers like to keep all pump drives powered up because they liked to run them every few weeks to check shaft seals and observe suction & discharge pressures.
 
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