Recommended test voltages for insulation resistance testing. SKF Baker AWA-IV 4 kV, Baker AWA-IV 12 kV, Baker AWA-IV 12 HO, Baker AWA-IV Series, Baker AWA-IV 2 kV

Test procedures

Recommended test voltages for insulation resistance testing

The following table provides guidelines for DC voltage applied during insulation resistance test. Test voltage should be applied for one minute. (See IEEE 43, sections 5.4 and 12.2.)

Winding Rated Voltage (V) a

<1000

100–2500

2501–5000

Insulation Resistance Test Direct Voltage (V)

500

500–1000

1000–2500

5001–12,000 2500–5000

>12,000 5000–10,000 a Rated line-to-line voltage for 3-phase AC machines, line-to-ground for single-phase machines, and rated direct voltage for DC machines or field windings.

Recommended test voltages for HiPot and Surge tests

The general recommended voltages for HiPot and Surge testing a motor, generator, or transformer are twice the AC line voltage plus 1000 volts.

2 x AC line voltage + 1000 volts = test voltage

This test voltage is consistent with NEMA MG-1, IEEE 95-1977 (for test voltage greater than

5000 volts), and IEEE 43-2000 (test voltages less than 5000 volts).

For example, the test voltage for a 480-volt AC motor would be:

2 x 480V + 1000V= 920 + 1000 = 1960 V

Likewise, the test voltage for a 4160-volt AC motor would be:

2 x 4160V +1000V = 8320 + 1000 = 9320 V

For new windings or rewound motors, the test voltage is sometimes increased by a factor of

1.2 or even 1.7. This provides for a higher level of quality control on the work performed.

For example, for the 480-volt motor, the test voltage would be:

1960V * 1.2 = 2352V

Or

1960 * 1.7 = 3332V

80 PUB CM/I4 71-015 EN V13.2 Static Motor Analyzer—Baker AWA-IV User Manual