Has anyone experienced a small(< 30V) voltage on a hoist hook when the crane (480 VAC) is grounded through the wheel-to-rail connection as allowed by NEC 610.61. Is it a problem? How large can the voltage get.
Originally it was around 30 weight, however, they are now recommending a 90 weight, which is what was put into gearbox. Now they say it is okay to return to the 30 weight.
The bearings appear to be fine. It has been suggested that the noise is due to the oil change and that possibly we should put the old oil back in????? I have just never heard of this type of problem.
I have a 85 ton hoist with dual gearboxes that have started making a semi-grinding noise on lowering and raising with little or no load. The gearboxes are over 50 years old, but the operation is very limited(say 200 hours per year)
The oil was just changed (possibly for the first time) using a...
Thanks for the responses. I wasn't sure if the existing setup gave us redundancy. I mean with the 13.8KV being fed to the 13.8kv/480 volt transformers via a single feeder breaker. A loss of that breaker would result in a total loss of 13.8KV. If I understand then there is no problem feeding...
I have a distribution system described as follows(basics only) (3) 115Kv/13.8Kv Xfmrs with the three 13.8 buses tied together. two of the 13.8 buses feed (4) 13.8Kv/480v transformers that feed 4 seperate buses. These 480v buses have cross-ties that form a ring bus. The normal arrangement is for...
Is there a ASME standard that addresses the criteria for performing a shaft alignment check? If you have a flexible coupling installed, does checking the shaft alignment without un-coupling yield any useful information?
