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Entry type: FAQ Entry ID: 109751788, Entry date: 11/06/2017

How can the insulation of a SIMOTICS DC motor be tested?

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Insulation test
Before being shipped, all SIMOTICS DC motors (1G/H.5/6/7) are subject to a withstand voltage test:

1. Test voltages
Tested according to:

IEC 60034-1, EN 60034-1 for Europe
NEMA MG 1; IEEE 112/7.2; IEEE 115/2.05 for the Americas
The highest rated voltage is used for the test.
Rated input/test voltage AC / DC (Vp)
Up = 2 x rated voltage + 1000 V (min. 1500 V)

2. Tested circuits
For the withstand voltage test, the test voltage is applied between the winding and ground (motor frame). For motors with rated voltages U N > 1kV, each winding phase is individually tested.

3. Test
The withstand voltage test is used to test the insulating capability of the insulation of parts and components at a specific voltage with respect to ground and/or with respect to one another. It is considered to have been successfully completed if, during the specified test duration, the full test voltage is applied and neither arcing nor flashovers occur.

4. Test duration and test voltage characteristic
The test is started with a maximum of half the test voltage, and is continuously increased to the full test voltage within 10 seconds. The test duration with full test voltage is 1 min.
Test duration when the full test voltage is applied: 1 min.
Maximum gradient of the up/down ramp: dU/dt = Up / 10 s.
For series testing of motors with U N ≤ 690 V and P N ≤ 200kW, it is permissible to replace the one minute test by a test with a 5 second duration at 120% test voltage.

5. Repeating the insulation test/withstand voltage test
It is not permissible to repeat the withstand voltage test with full voltage on motors when delivered from the factory.
If the customer requests that the withstand voltage test is repeated, then this test must be performed with a reduced voltage:
Repeat tests for motors according to IEC with 80% * U P.
Repeat tests for motors according to NEMA with 85% * U P.

For more information on insulation tests on a SINAMICS DCM see Entry-ID: 85519568.

Please contact CS LD Customer Care Center if you require additional information:

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