Robicon VFD trips on under voltage
Robicon VFD trips on under voltage
(OP)
I am working with an old Robicon VFD, model 422, installed around 1981. It powers a 40 hp GE motor. Instabilities in incoming power cause it to trip on under voltage. Under voltage condition lasts less than a second and is back up to rated. Vendor manual indicates board PC1 has this circuitry. In researching board schematics it does not appear that there are any delays or adjustments possible. Does anyone have any experience with this type of drive? Any delay or adjustment possible on undervoltage trip circuit?- Thanks





RE: Robicon VFD trips on under voltage
Newer drives are somewhat better with undervoltage ride-through and automatic re-starting.
I'd say it was time to retire that 1981 VFD and see if Robicon (Siemens) wants to put it in their museum.
RE: Robicon VFD trips on under voltage
RE: Robicon VFD trips on under voltage
RE: Robicon VFD trips on under voltage
I agree though that it may be time to consider replacement. As LionelHutz suggested, the main power caps have deteriorated as well (likely). If that's the case then it may be worth getting the better performance and efficiency from a newer drive rather than costly repairs to that one.
Still, 27 years operation from a VFD is, in my experience, one for the record books! I would think it worthy of a write-up by Siemens / Robicon (in exchange for a small repair job?) and I'm sure they would be happy to hear from you.
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