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Join Date: Jan 2013
Posts: 1

Identification of Terminals u1 v1 w1 w2 u2 v2 ,

01/11/2013 12:57 PM

i received a three phase motor 86 kw which does not have any terminal box in the motor and wires are also not marked , i try to find the winding i marked six wires as 1,2, as one coil 3,4 next coil and 5, and 6 the third coil , actually it is connected to a star delta starter , now i connect 1, 3, and 5 to main contactor and 2, 4, 6 to the delta contactor when i start the motor in star it is working but as soon as it switch to delta the breaker trips , that was a 100 amps breaker i thought it is small then i changed it to 150 amps breaker but still the breaker is tripping , i tried interchanging wires but of no use i am confused pls give me some suggestion how to find out the terminals what i am connecting is correct, is the breaker small how much starting current a 86 kw , 380 volts motor need in star delta . pls help me how can i solve this problem.

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#1

Re: identification of terminals u1 v1 w1 w2 u2 v2 ,

01/11/2013 12:59 PM

Ask the motor manufacturer to indentify them for you.

There is probably a schematic on their web site that will guide you.

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#2

Re: Identification of Terminals u1 v1 w1 w2 u2 v2 ,

01/11/2013 8:08 PM

Reversed windings.

Rare but not unknown in a motor returned from a rewind. One out of the three windings has it's start and finish swapped over. For a 400V motor use a 50V AC supply to carry out the tests. Basically we need to make the motor becomes a three winding transformer. Then by measuring the voltage of the secondary the start and finish of each winding can be found.

With the windings correct you can move the meter and test link to any of the following positions and get 0V. If you get 110V twice in the test, you've got a reversed winding.

If unfortunately you manage to pick a reversed winding to start testing it would appear on the first test to be correct by giving 0V output.

Once you move the test voltage to the other windings you will get 110V output. The reversed winding will be common to each pair of output windings that have given 110V.

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#4
In reply to #2

Re: Identification of Terminals u1 v1 w1 w2 u2 v2 ,

01/13/2013 11:27 AM

If you have 6 leads, pairing them into 3 sets is possible by continuity test

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#3

Re: Identification of Terminals u1 v1 w1 w2 u2 v2 ,

01/12/2013 12:37 AM

tonys is correct, you ensure the following also,

1. full load current of motor

2. tripping curve of breaker

3. the motor is dual speed or not

check this article also, http://cr4.globalspec.com/thread/71498

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