Three Phase Motor Test with Multimeter
Testing diagram and testing procedure.
1- Three Phase Motor Test with Multimeter:
Three phase motor is checked when it is faulty or after rewinding. Many methods are available for testing or check three phase motor. Multimeter test method is given below mentioned.
Three phase motor has three windings, one is R phase, second is Y phase and third is B phase. Firstly, power connection is disconnected from connection plate then motor can be tested below mentioned procedures.
Multimeter is a test instruments which is used in commonly for winding coil insulation test, open circuit test, short circuit test.
2-TP motor testing diagram with multimeter :
3- Types of three phase motor test :
Mostly three types problems are found in motor as below mentioned.
- Insulation resistance test.
- Coil open test.
- Short circuit test.
4- Insulation Resistance Test:
All three-phase windings insulation is tested with multimeter methods. in this test all three-phase winding insulation is checked. Is it ok or failure? 3 phase windings donate as u, v and w, which are mentioned on terminal plate as U1, V1, W1, and W2, U2, V2. Multimeter knob is selected on resistance mode for resistance checking.
1- R phase winding insulation test.
Multimeter leads is connected with U1 and U2 terminal. The value of resistance should be note down for comparison with Y and B phase resistance.
2- Y phase winding insulation test.
Multimeter leads are connected with V1 and V2 terminal. The value of resistance should be note down for comparison with R and B phase resistance.
3- B phase winding insulation test.
Multimeter leads are connected with W1 and W2 terminal. The value of resistance should be note down for comparison with R and Y phase resistance.
4- R, Y and B phase resistance comparison.
Note down resistance is compared with each other. If the value is same then winding insulation is ok. If the any winding resistance is very low or high then winding insulation is burn or failure.
5- Open Circuit Test:
In this test all three-phase winding continuity is checked. Is it close or open? Three phase windings are marked as u, v and w that are mentioned on terminal plate as U1, V1, W1, and W2, U2, V2. Select the multimeter knob on the continuity mode.
1- R phase coil open circuit test:
Multimeter leads are connected with U1 and U2 terminal. If the continuity sound is coming or value on screen is something then winding is close. If the continuity sound is not coming or value is zero then the winding is open or break.
2- Y phase coil open circuit test:
Multimeter leads are connected with V1 and V2 terminal. If the continuity sound is coming or value on screen is something then winding is close. If the continuity sound is not coming or value is zero then the winding is open or break.
3- B phase coil open circuit test:
Multimeter leads are connected with W1 and W2 terminal. If the continuity sound is coming or value on screen is something then winding is close. If the continuity sound is not coming or value is zero then the winding is open or break.
6- Short Circuit Test:
In this test all three-phase winding continuity is checked with each other and motor body. Three phase windings are donated as u, v and w that are mentioned on terminal plate as U1, V1, W1, and W2, U2, V2. Select the multimeter knob on the continuity mode.
A- Short circuit test between R and Y phase winding:
: Multimeter leads are connected with R and Y phase winding as terminal U1, U2 with V1, V2 terminal. If the continuity sound is coming or value is showing something. It means both winding is short condition. If continuity sound is not coming or value is zero. It means the windings are not short or ok condition.
B- Short circuit test between Y and B phase winding:
Multimeter leads are connected with Y and B phase winding as terminal V1, V2 with W1, W2 terminal. If the continuity sound is coming or value is showing something. It means both winding is short condition. If continuity sound is not coming or value is zero. It means the windings are not short or ok condition.
C- Short circuit test between R and B phase winding:
Multimeter leads are connected with R and B phase winding as terminal U1, U2 with W1, W2 terminal. If the continuity sound is coming or value is showing something. It means both winding is short condition. If continuity sound is not coming or value is zero. It means the windings are not short or ok condition.
D- Short circuit test between R phase winding and body:
Multimeter leads are connected with R phase winding and motor body as terminal U1, U2 with motor body. If the continuity sound is coming or value is showing something. It means R phase winding is short with body. If continuity sound is not coming or value is zero. It means the R phase winding is not short with motor body.
E- Short circuit test between Y phase winding and body:
Multimeter leads are connected with Y phase winding and motor body as terminal V1, V2 with motor body. If the continuity sound is coming or value is showing something. It means Y phase winding is short with body. If continuity sound is not coming or value is zero. It means the Y phase winding is not short with motor body.
F- Short circuit test between B phase winding and body:
Multimeter leads are connected with B phase winding and motor body as terminal W1, W2 with motor body. If the continuity sound is coming or value is showing something. It means Y phase winding is short with body. If continuity sound is not coming or value is zero. It means the B phase winding is not short with motor body.
