Good morning/ Afternoon ...I have a genset i am currently trying to troubleshoot. The phases was unhooked from the lugs,,and relanded. Now when i go to turn the gen back on it reads "generator rotation phase mismatch" when in idle and shuts down. The gen is a CAT model 3512, rated 1419. The control panel at the mcc is EASY Gen 3000, Woodeard brand.
generator reading phase mismatch
- Thread starter wpoe
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Tulsa Electrician
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- Tulsa
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- Electrician
I'm sure you did however have to ask. Marked, unhooked and landed same order. Nothing else changed.
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Tulsa Electrician
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- Tulsa
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- Electrician
Your phase sequence should be marked at connection point. I do believe code requires this.
hillbilly1
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- North Georgia mountains
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- Owner/electrical contractor
Is this co-generation? Usually the generator does not monitor rotation, that is usually up to the transferswitch, which may, or may not have rotation sense. Sounds like the phasing got crossed up during reconnection.
yes i did
its the Easy Gen 3000 that reads its when bringing it online. The phases was crossed up from beginning and i had to swap em back to original way but it still reads the same code as before at the mcc, even after done corrrectly.
synchro
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- Chicago, IL
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- EE
Is the parameter for CW or CCW direction set to the way you want it? CW would be standard L1, L2, L3 rotation.
yesterlectric
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- PA
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- Electrician
Well the fact that the conductors were disconnected and re-connected gives good reason to investigate that there could have been a phase reversal. However I have seen intermittent phase sequence mismatch shutdowns on 2 brands of generators. Same power system. No changes. Just at random. Sometimes it's a controller firmware issue that causes intermittent tripping. I also have a hunch that if there's changes in load or voltage right at the time it is trying to sync that this could cause some controllers to trip. If you're confident there were no mistakes in anding the cables then contacting the manufacturer may be helpful.
Is this a medium voltage generator? If so you might be doing phase sequence checks on the secondary of a potential transformer. Did you have someone verify phase sequence before the cables were removed?
My opinion is that it is better to use "phase sequence" or A-B-C instead of "phase rotation" because some engineers I have interacted with think automatically of "phasor rotation" in which phasors are graphed out at counterclockwise rotations. This company makes a meter that spins CW on ABC and another that spins CCW on ABC. You buy the one that makes you feel best!
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Is this a medium voltage generator? If so you might be doing phase sequence checks on the secondary of a potential transformer. Did you have someone verify phase sequence before the cables were removed?
My opinion is that it is better to use "phase sequence" or A-B-C instead of "phase rotation" because some engineers I have interacted with think automatically of "phasor rotation" in which phasors are graphed out at counterclockwise rotations. This company makes a meter that spins CW on ABC and another that spins CCW on ABC. You buy the one that makes you feel best!
hillbilly1
Senior Member
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- North Georgia mountains
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- Owner/electrical contractor
That could be it if it doesn’t correct by swapping two phases, the newer ASCO transfer switches have to be programmed ABC or CBA to match incoming. Seems like Kohler is the same way.
yes the sequence is counterclockwise
yesterlectric
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- PA
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- Electrician
I realize now this may be a generator without a breaker used for synchronization mounted directly on its case. Makes things a little different.
Joethemechanic
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- Hazleton Pa
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- Electro-Mechanical Technician. Industrial machinery
Just to make sure I'm understanding this. This generator is run in parallel operation with some other 3 phase source? Is it starting up and not syncing due to phase order or frequency? What voltage? A 3512 can be up to 13.8kv. Roughly how old is this unit? Is it a mechanical or electronic governor?
hillbilly1
Senior Member
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- North Georgia mountains
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- Owner/electrical contractor
Sounds like the generator is not liking the power it is putting out, perhaps a lost phase? That would probably set a rotation mismatch, as it would be single phasing.
it is rated at 1419 kva and 1135 kw. 480 volts and in parallel with other generators with Easy gen 3000 mcc. so it has an electronic governor.
synchro
Senior Member
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- Chicago, IL
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- EE
Do the points where the voltage is monitored by the control unit on both sides of the circuit breaker correspond to each other? For example, if the generator side of one pole of the circuit breaker is monitored by the L1 input of the control unit, then I believe the output side of breaker needs to also be monitored by the appropriate L1 designated input. And the same for the other poles. I don't think the setting for CW or CCW rotation can compensate for a mismatch of these connections.
Joethemechanic
Senior Member
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- Hazleton Pa
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- Electro-Mechanical Technician. Industrial machinery
I was kind of thinking something simular. But if the sensing was crossed up, wouldn't it fool the switch into closing when the phases were not in sync. Of course the results would be disastrous. I would think there must be some kind of redundant system to prevent this
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
This is basically what your easygen 3000 is doing. I'm not saying you don't understand it. But just for educational purposes for anyone who might read this thread
And this lamp method is a very old school method.
And this lamp method is a very old school method.
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