Search results for query: *

The series field D1 and D2 was being shorted by the hand/auto switch in the auto mode but not in hand mode. I attached the schematic in earlier post. You will see the switch does short the winding but should only do this in the off position (presume a safety feature to ensure finding is...

turned out to be fault internal to hand/auto switch!!!

Maybe i wasnt clear but the results taken were for two different generators. First results are for our problem generator in auto. The 2nd set for another generator generator which is ok in auto up to full load. We wanted to also compare manual results for both sets as well but didnt get the...

apparently no one has touched series field circuit, so assume this to be o.k. at moment, wire number check seems to tally. replaced compounding diode assembly and no change attached are sum results in auto for the fault gen versus one with no probs. seems avr is firing at the front stop at...

check out rotating diodes and were o.k., also changed out with other healthy machine. same issue resides. see attached for configuration. currently in process of checking compounding diodes and resistors. any other ideas greatly...

Thanks scotty, yes i did wonder if we may be overdriving in field. Also thought about looking a waveform, but would not have been looking for faint communtation notches so will look at that. The avr output bridge rectifier was also swapped out with one from a known working set. Apart from...

We have a ships brushless ac 440v 450kw 0.8pf generator which is experiencing issues in auto control, would appreciate any ideas for further fault finding. In hand control can achieve rated output In auto we can deliver 100% rated kw out of set in auto control In auto above 50% rated kva the...

Thanks dpc. I had read something similar.... http://www.ecmag.com/section/systems/conductors-connected-parallel I wouldn't really think at starting to run parallel below 50 or 70mm.sq (which is similar to the 1/0 awg you quote). I could only think maybe manufacturer tolerance in...

what is reason for minimum conductor size that can be run in parallel (other than economic and labour intensity). I am working to marine/offshore rules that state minimum c.s.a that it is permitted to start running conductors in parallel is >10mm.sq. someone asked me if they could run 2 x...

could someone summarise correct procedure for load bank testing generators (individually) and then operating in parallel. Should procedure be:- Individual generators 1. gradually increase load from 0-100% (kW) with generator set in droop mode and confirm correct droop characteristic 2...

Thanks all. Electricpete. Yes, I had read that IEEE522 was o.k. for random and form motors (LV included) despite the title of the standard suggesting it is just for form wound motors. The more I looked into it, it seemed to suggest that it was only a suitable test for high voltage motors that...

we have old motor going for overhaul and OEM recommended procedure written at time of manufacturer (1978) was to DIP and bake. Would you recommend now to VPI? Also regarding test (it is 440V 300kW motor), is a surge test applicable for this random wound machine?

A specification for some control equipment has a statement "welding within 10m vicinity of control equipment disconnect power otherwise supply filters might be damaged and control system function can be jeopardised." Is this common? it is fairly important equipment and I have not come across...

Are you permitted to use 600/1000V grade cable on a 690V IT system that would run with earth fault for >8hrs? or should you use 1900/3300V cable?

great stuff, thanks both

thread237-29369 Does anyone have a copy of the paper by Richard Nailsen that was referenced in this thread?

yes catserveng you are near enough correct in describing the philosophy. Thanks all, it seems as I thought that it needs some careful consideration.

Thanks Waross, yes these were my concerns. I don't know the details on the load sharing/governing on each system at present and I would think the kVAR load sharing is maybe not even included. You mention "Further more, the power flow between the generator groups will depend on the phase angle...

with reference to attached sketch we have a distribution system that is currently operated with two generator plants that are independent, i.e. the 690V switchboard operates independently of the 480V switchboard. Somebody has come up with the idea of reusing an existing sub-distribution feeder...

I have been passed a battery test report to look at( which covers NiCd and Pb battery banks) Are there any good references or threads that I can look at to help me. Thanks