Repair manual

Troubleshooting GP Repair
wc_tx000548gb.fm 62
4.10.8 Using the Ohms setting on the multimeter, measure the resistance of
the rotor winding by measuring across the slip rings (e). Each
generator size will have a different value. Check the chart in the
graphic for the correct values; use a tolerance of +1.0/-0.0 Ohm.
• If the correct resistance is not measured, the rotor winding is bad;
replace the rotor.
• If the correct resistance is measured, the rotor winding is OK.
4.10.9 Check for shorts to the rotor shaft by measuring resistance between
each slip ring and the end of the rotor shaft.
• If there is any resistance, the rotor winding has failed.
• If there is no resistance, the rotor winding is OK.
4.10.10 If possible, the resistance of the insulation should also be checked
using a 500V megger or similar instrument. When using a megger, a
resistance value of at least 1 megohm should be obtained. Measure
between each winding group and the generator frame. If 1 megohm is
not measured, dry out the windings in a warm atmosphere and recheck
every 30 minutes until 1 megohm is obtained.