Dual Voltage Motor

By the content of you post send it out to a repair company to have it tested.

I did not wire the motor by myself and it was tested by the guy in the drydock and they just told me the guy made a mistake on the test.I have confirmed the motor and connect it properly and it runs on delta and wye without trouble, but again im in doubt because my megger test on the other winding is far less and is only 10 mega ohms and it should be infinite.

Agreed, and OP said it actually works as it should when connected properly and energised.

If it doesn't smell when it is in service then it's OK.

If the OP is still paranoid then he might want to perform another meggar test when the windings (and their insulation) have warmed up.

Well i do certainly know before testing that the motor is infinite because i checked it prior docking, the motor have separate winding for delta and wye, both are powered by 440 volts 60hz.Thanks for your info.

Thats fine.

In the RN we accepted anything above 1 MegOhm as being OK. I use this value here in Germany.

I believe the UK as a whole accept this as a minimum value, maybe someone from the UK could chime in and confirm/deny this....

Throw a photo of the terminal block and designation plate into this discussion please.

I notice the OP didn't respond, but I must say that is not the option it once was. For me to do the same with a questionable motor, I would have to send it to a company over 100 miles away, and wait for three weeks for a return. (we've checked this out recently) Note that this is an area with literally thousands of electrical motors running in outdoor conditions daily. (middle of the oil fields in Pa - most wells are pumped with an electric motor) The norm now is to replace - not repair. Both the local repair facilities shut down more than ten years ago for lack of business.

...or back to the motor manufacturer for testing.

Thats what I say too. So I give you a GA since I cant give one to myself!

haha, thanks

Or connect it properly and try if it is still ok!

Can't fail the test if properly connected isnt it?

I suspect that you will never know if this motor is still OK. I say this not because of the motor being miswired. I say this because your question implies that you do not know yourself if a motor is functioning properly. If you did know how to test a motor then you would already have properly wired this motor, turned it ON, and tested it. Instead you must rely on somebody else that knows electric motors in general to test this motor.

Send it back to the manufacturer and expect to pay a fee.

What kind of nose do you have.

A shellack nose sniffs burnt shellack isolation from the windings, and most of the time a bad motor exposes this. Even years after.

Google shellack nose.

I don't think I have ever heard of a 6 lead dual 440 voltage Delta Wye motor.

What was it used for and how large is it?

It was used for a steering gear and when it was tested recently after the accident it did run to delta and also run from wye connection, but upon meggertest the delta connection gives only 10 mega ohms of insulation while the y gives infinity.

Y is gone

Get yourself a megger and ohm meter, familiarize yourself with their proper use. Especially the megger it will lite you up. Then use your search engine, key words: How to check a three phase motor. It's electrical 101 you can figure it out easy enough.

Let us know the nameplate details and 6 terminal markings

Obviously i find it very very helpful indeed . thank u for your help.

you're welcome

So, the facility cannot wire the motor correctly in the first instance, cannot check that it is correctly wired before energising, and it expects to be able to prove the motor is OK having come through the experience in the second?

How abstruse.

Some of you clowns here really need to get a life other than jumping down the throats of posters that don't mesh with your perceptions.

Vitroid GX,

TcmTech has a good point re: your meggar test.The only thing I could add is that without a baseline reference from as new condition (meggar readings), you really don't know how healthy your motor is and need to rely on accepted practices & standards.Which TcmTech has provided.

I can see why you would want to make extra sure of your motors reliability/safety.

The next step would be to test the motor under both partial and full loads and see if your readings change.

I couldn't say how to interpret any changes but someone here maybe helpful.

brich, I appreciate your helpful input.

Cheers

J

True enough, which makes me wonder why the OP is really worried.

What else really happened?

Liked your post!!

What I cannot imagine is how on 3 connections, the coils are in a star and on another 3 connections they are in Delta unless they have two sets of windings, completely separate from each other......

Are motors made like that? It just seems like a big waste of space to me.

We had such motors with 6 connections, two for each field coil, but we had to connect them on a connector block to form either a Star or a Delta configuration.

What am I missing Guys?

What you describe with the 6 connections is right. How one interconnects these for energising determines whether it is star or delta.

All six terminals can be wired back to a remote location to a star delta switch that permits either as required. Starting in star and then switching to delta is routine.

Another guess here, in lieu of info from OP, is that the star delta motor starter was mal connected and both contactors pulled in at the same time. Even so the circuit protection should have controlled smoke release. OP might also want to be looking at fried or lightly toasted contactor terminals if he is still searching for collateral damage resulting from an installation error.?

Chances are nothing happened... The same phase luckily got connected to the end of each coil....Most dual voltage motors have six leads so that you can connect them in either wye or delta configuration. A quick check to the manufacturer's website should give you the info you need. The motor will have 3 phase coils starting at 1 ending at 4, starting at 2 ending at 5, starting at 3 ending at 6. A wye connection will have your 440v phase feeds connecting to 1,2,and 3. The terminals 4,5,6 will be connected together to form the wye point. If you connect it in DELTA... the Phase voltages feeding the motor will have to be 240v.