Reply to Barry1961
I am also very surprised. The latest drive lasted approximately two months.
All the hoist drives have external resistors. Bridge and trolleys are the only ones without it.
I am still not sure why the control boards went. Hopefully Baldor will have something to add.
Thanks you all for your feedback.
A few notes.
In regards to the power pickup, The crane is fitted with a dual pickup system. Even so, I did do some monitoring and was unable to find any irregularities.
Filtering is done with inductors. I have never used harmonic filters, are they effective...
I have two A.C. overhead cranes on the same runway (same power pickup). They have been in service for a number of years. The cranes are feed by a 600 volts 3 ph. supply. All axis are controlled by VFD or Vector drives.
Over the last year, I have had to replace the Bridge drives on both cranes...
I would like to invite comments on the value of measuring impedance on rebuilt D.C. motors. I find that the impedance value of newly manufactured coil varies substantially compared to original coils. This is due to the coil manufacturing process. Although the motors pass all other statis &...
