4160 phase rotation verification
4160 phase rotation verification
(OP)
Hello all:
I am putting a new 4160V diesel genset in service on an existing med voltage transfer switch. To verify phase rotation I have a 25kV meter with two probes. I plan on reading utility A to gen A and so on with B and C, watching them go to zero volts as they drift in and out. If all three drift to zero I have the right rotation...accurate??
I am putting a new 4160V diesel genset in service on an existing med voltage transfer switch. To verify phase rotation I have a 25kV meter with two probes. I plan on reading utility A to gen A and so on with B and C, watching them go to zero volts as they drift in and out. If all three drift to zero I have the right rotation...accurate??






RE: 4160 phase rotation verification
RE: 4160 phase rotation verification
1> Find some 4160/120 PTs and extend the 120 volt leads so that you don't have to go near the 4160.
Bill
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"Why not the best?"
Jimmy Carter
RE: 4160 phase rotation verification
RE: 4160 phase rotation verification
Please see attached thread.
thread238-189772: SYNC CHECKING (machine rotating opposite to system)
All best solutions are included.
Good Luck.
Slava
RE: 4160 phase rotation verification
Regards
Marmite
RE: 4160 phase rotation verification
if the two systems are not refererenced to ground,one can get false results if the testing is completed expecting to test as if the two systems are referenced to ground!
Jim
RE: 4160 phase rotation verification
Two sets of analog voltmeters rated for the voltage. Access to the three hot terminals of both systems. The appropriate personal protective equipment and safety standby people.
With both systems hot and frequencies pretty closely matched, place one voltmeter with one probe and "a" of one system and "a" of the other. Place the other voltmeter on one of the other phases likewise.
Observe the voltmeter needles. They will both swing as the voltage of one system swings in reference to the other due to a slight frequency difference. If the rotations one both systems are the same, the needles on the two voltmeters will swing in the same direction together. If they are not, then the needles will swing in opposite directions. This isn't a subtle difference. It is obvious when you see it. You can move one probe to another phase to see what it looks like.
As for using PT secondary voltages to do the checks, this is good too, if you're ABSOLUTELY SURE of the wiring on the PT's. I've seen a few that weren't right. This would be a bad time to find out.
I've not had real success with using the new digital voltmeters due to response time for display.
old field guy
RE: 4160 phase rotation verification
I appologise profusely for my mistake. (Maybe I need more coffee... Maybe less)
Bill
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"Why not the best?"
Jimmy Carter
RE: 4160 phase rotation verification
Please don't angree on me, but Canadien filter coffee is..., no words.
Regards.
Slava
RE: 4160 phase rotation verification
Brian
RE: 4160 phase rotation verification
No, you're not reading it correctly; you can't do it with sequential measurements. It may work, but it may not work, and if it doesn't work it will not work spectacularly
RE: 4160 phase rotation verification
regards,
Brian
RE: 4160 phase rotation verification
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 4160 phase rotation verification
You only need to take rotation check (using a phase rotation tester) on the PT's three terminals of each source(on the MVTS PT's and on the diesel gen side PT's). Be sure you correctly wire the PT's and mark each terminal A, B, and C. Check if the rotation is ABC or CBA on each terminal set. If they are of the same phase rotation, then its okay to tie both sources.
Regarding reference problems, you always ground the neutral of PT's (the phase rotation tester I used is rated 500V, so no problem with testing equipment being busted). It doesn't take long.
RE: 4160 phase rotation verification
I would strongly recommend getting a local electrical testing company or competent electrical contractor to do the phase checking on a medium voltage machine if you are not positvely sure how to do it. I don't feel the risk of having someone who isn't sure of how to make those essential checks is worth the money you would save by not having a qualified entity perform that service for you. Then you could observe and decide if you want to gear up to make those kinds of checks on your own in the future. Safety first!
Hope that helps.
RE: 4160 phase rotation verification
At this case, only Mike ( Catserveng) is right. Don't take chance, if don't sure.
Star to Mike.
Best Regards.
Slava
Safety first!!!Always!!!!!
RE: 4160 phase rotation verification
regards,
Brian