Was looking at a Generator wired at 277/480 and checked for continuity from phase to phase with ohm meter and had .5 ohms with buzzer ringing for continuity at output breaker , does this mean phases are shorted ? shouldn't they read infinite?..If not help me understand how they are interconnected but not shorted..
Please help

Thanks

 

Yes that sounds about right. I am sure somebody will explain CEMF in great detail for you but think about phase to phase resistance on any decent size motor, Typically relatively low... which makes sense why we see the motor inrush currents when the motor is starting.

 

The phases on a generator are connected through the generator windings, which will have a low DC resistance. See the below link on 3-phase power which illustrates this. http://en.wikipedia.org/wiki/Three-phase_electric_power


Bill

William (Bill) L. Mostia, Jr. PE
Fellow
SIS-TECH Solutions, LP

Any information is provided on Caveat Emptor basis.

 

So then this reading is normal? And everything is fine as far as it not being shorted anywhere?

Thanks for responding guys..

 

Ok , I was thinking there was bigger problems with the unit..Initially it had a resistor or varistor on Generator end that was melted apart attached to Bridge rectifier on Gen end..Also noticed Voltage regulator had visual damage at harness connection on both regulator and harness...I checked the exciter stator and had 6 ohm resistance which indicated it was fine..So I ordered the parts mentioned (Bridge rectifier assmy, voltage rectifier, and harness) but was trying to dig deeper to find the root cause of failure...And also didn't want to replace these components and start unit and repeat the problem smoking a brand new regulator..Any help would be greatly appreciated as I am striving to learn as much as possible on the subject.

Thanks,
Chris