Dormant VFD Drive
Dormant VFD Drive
(OP)
We have an A-B 1336 Plus II VFD that we have stored for about 2-3 years. Drive is rated at 150HP and has never been powered up. I have been cautioned about applying full line voltage to the drive, rather to apply a lower voltage and slowly increase the value. A Yaskawa FAQ article refers to this as "reforming." Anyone have details what to do for the A-B drive?





RE: Dormant VFD Drive
Regarding time: There used to be a graph with hours vs months, where hours indicated time required to go from zero to full voltage and months told how long the inverter had been out of service. Cannot find it any more. Take your time and use most of the day for it. Increase 20 percent every hour (five hours in all). That should be a safe procedure.
RE: Dormant VFD Drive
"Venditori de oleum-vipera non vigere excordis populi"
RE: Dormant VFD Drive
RE: Dormant VFD Drive
If you connect across the DC bus, you will still be connecting across the capacitor bank. As recommended by others, it is best to form the capacitors first.
From the DC bus, you could use a large resistor in series so that there is a very slow charge up time.
When the capacitors have been formed, the slow charge should still be applied every time you power up, but can be a fraction of the time required when forming the capacitors.
There is a soft charge circuit built into the drive that operates when the AC is first applied.
Best regards,
Mark Empson
http://www.lmphotonics.com
RE: Dormant VFD Drive