Phase rotation advice

[Phil]

Hello all,
I'm after some advice on my current situation as I've never came across this before and trying to find answers online are not producing any results.

Basically I've got a 3 Phase motor, checked voltages across the 3 lines and neutral, everything is as it should be.

Checked rotation, L1 to L2 ok, L2 to L3 is not showing rotation but it's showing 400V, L3 to L1 is ok.

Why would L2 to L3 not show rotation but will show 400V?

Thank you for any advice.

 

[Pete999]

I don't know if this link will work from Google photos.
https://goo.gl/photos/NVQmta5qwXiutE3w7

Sorry about the quality, trying to record on the phone with one hand and test with the other.

To add to the confusion, when I load tested the generator, all three phases displayed correct rotation.

You need a new tester Phil.

 

[Pete999]

I don't know if this link will work from Google photos.
https://goo.gl/photos/NVQmta5qwXiutE3w7

Sorry about the quality, trying to record on the phone with one hand and test with the other.

To add to the confusion, when I load tested the generator, all three phases displayed correct rotation.

You need a new tester Phil.

 

[Phil]

You need a new tester Phil.

Do you think everything is as it should be? I can get a new tester when I get back to the depot today or tomorrow.
I'm just really confused why it doesn't show up L2 to L3 but does L3 to L1.
I'm just trying to rule everything out before the hoist engineer turns up starts blaming the generator.

 

[telectrix]

maybe some dark red medication from Chile or Italy might help?

 

[Pete999]

maybe some dark red medication from Chile or Italy might help?

Yeah give it a try this PM

 

[shaun1]

Does it always show no rotation L2 to L3? Does it always show correct rotation between other phases? If so that would suggest there is something different about that measurement, but probably worth checking with a second meter.

If you use the probes the other way round do you get Phase rotation (the opposite way)?

When you added the load from the heater did you still get 400v between all phases?

 

[Wilko]

If you are doing what Pete's video shows and you are only seeing rotation in 2 phases, then doesn't that mean you only looking at 2 phases? Test method, test instrument or labelling wrong perhaps?

 

[shaun1]

If you are doing what Pete's video shows and you are only seeing rotation in 2 phases, then doesn't that mean you only looking at 2 phases? Test method, test instrument or labelling wrong perhaps?

I think the confusion comes from the fact that the meter still indicates 400v L2 > L3

 

[Wilko]

To add to the confusion, when I load tested the generator, all three phases displayed correct rotation.

Ok - so what is different in these two situations?

 

[Pete999]

You need a new tester Phil.

I could be barking up the wrong tree, your tester Phil does not have the L1 L2 markings, although there there are L/R sequence lamps, as I say maybe completely wrong, but are you sure the tester show is capable of doing Phase Sequence testing? It's just a thought. Could it be as someone has already said, your test method is wrong?

 

[davesparks]

How good is the earth reference for the generator? Those two wire rotation tests rely on the source being properly earthed as they take an earth reference via capacitive coupling to the hand of the operator.

I think you'd be better off testing phase rotation with a proper phase rotation tester or mft with this function.

You said the generator is shutting down on reverse power, is it running in parallel with other generators?
Reverse power on a generator normally means that power is feeding in to this generator from another connected generator or other source.

 

[Pete999]

How good is the earth reference for the generator? Those two wire rotation tests rely on the source being properly earthed as they take an earth reference via capacitive coupling to the hand of the operator.

I think you'd be better off testing phase rotation with a proper phase rotation tester or mft with this function.

You said the generator is shutting down on reverse power, is it running in parallel with other generators?
Reverse power on a generator normally means that power is feeding in to this generator from another connected generator or other source.

Backfeeding, of course, wondered what the OP meant with reverse power.

 

[westward10]

I think he means when the connected hoist motor which the generator supplies is reversed the genny shuts down.

 

[telectrix]

i think it's time for a beer.

 

[Pete999]

i think it's time for a beer.

Or that medication you were ion about ealier