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Dear all, I've experienced a similar incident with a 6MW-6kV-6p wound rotor motor before. We received that motor with some damages in the rotor bar connections due to some explosions. Our customer also reported of some failed starts, happened randomly in a long time period before motor...

I have the same idea with waross, that the original configuration for this motor is 900/1800rpm one winding, and one separate winding is 3600rpm. I deduced that according to zlatkodo's 2/4 pole diagram, the 4 pole winding could be overheated. Because this is only a single-star (1 path parallel)...

I agree that you need to have a check-up of the ventilation system of this motor. Especially the motor's been overheated after an overhaul. Take notice: -Is there something missing? For example an internal cooling fan or any shield? -Is there something on the wind-path being blocked? For example...

You have to make clear what is the problem with the motor running with 2/4 pole winding, before consulting others about that matter.

I agree with electricpete that "long jumper" connection spans an arc of 300 degrees. In practical usage (not to mention in multi-speed windings), in normal single speed winding, I only have encounters with 2 path parallel circuits using long jumper connections. I've never seen any winding with...

Hi electricpete, After a couple of days out of my office, back here seeing your discussions I myself am thinking of changing my concept of fractional q windings. My English is not very good, and I haven't got access to valuable sources of information, such as the book "Electrical Machinery", by...

Hi electricpete, I see your sequence in phase counting is different with mine. Yours is A-Y-C-X-B-Z so your lead assignment is different. But the conventional way is A-Z-B-X-C-Y. Anyway the diagram is still OK, no problem. Back to the Z=90; 14 poles diagram. One of our engineer, had put the...

We've just got an incident with a new winding. Z=90; 14 poles; Which slot should you pull out the T-leads? I just put forward for you to think before telling you what happened.

electricpete, I think both diagrams are OK now. But I still have one correction: -In 30slot-8p diagram, indeed B phase starts in slot 11, and C phase in slot 21. Otherwise you could have other options, like A-1, C-6 and B-11 (zlatkodo's) or B-26, A-1 and C-6, etc. -In 36slot-10p diagram, C...

Many thanks electricpete, I agree with your experiment analysis. Perfectly correct with a single phase circuit. But in three-phase circuit, you need to have a balance between three phases (electrically symmetrical). I am a rewinder myself. I remember once I (for experiment purpose) tried to...

To zlatkodo, In your given winding diagrams (dated Sep 10), the upper diagram might not applicable. There are two reasons: 1) The electrical angle between the U1-V1 and V1-W1 have to be n*120 degrees (n is a natural number). The slot-to-slot electrical angle alfa=p*360/Z=4*360/33=43.64 deg. In...

"Distance between the beginnings of three-phase windings is , generally, two thirds of the full pitch. But this may not always be so, it depends on which shortened pitch is used." This is only for general estimation. In fact, this distance depends on some factors: 1) Angle in...

Please check out IEC 60044-1 Instrument transformers: CT, and IEC 60044-2 Instrument transformers: VT for the ratings.