The fuses we are using is rated slow blow 20 amp. We have taken all the load off the secondary. Powering the transformer two to five times blows the fuses.
We have a 5000 kva transformer wired 480 volt on the primary and 230 volt on the secondary. This is a single phase transformer. When you power it up three to four times it blows the both primary fuses. What do you think is the problem.
Thanks,
RogerMM
The clamp on meter is a Fluke that one of the mechanic's own. It is about a year old and has been used to check other motors on VFD's. The VFD in question was working fine as long as we had the FLA set twice as high as the motor nameplate. Internally there had to be a problem with the unit...
We have resolved the problem. The manufacturing tech was unable to help us. We changed out the VFD and the display agrees with our clamp on meter. I appreciate everyone's help.
I have a VFD that the displays shows twice the current reading versus a clamp on meter on the motor leads. I have contacted the manufacturer and they have not resolved the problem. What do you think?
I would like to know what the effective voltage equation is for the PWM the motor sees as the volts/hertz ratio is held constant. If the effective is linear then, is it a direct ratio for volts and hertz? I.E. 230 Volts, 30 Hertz and so forth?
I would like to know what the actual output curves look like from a VFD. I have read several comments and from what I have read there is a difference of opinion. If the PWM voltage is constant and only the frequency is varied what is going on with the volts/hertz ratio? It may be that we must...
