z T r y Gr i Fig 8 23 Field Coil Test for Open Circuit lr z Fig 8 24 Field Coil Test for Ground frame and place other lead on ground on generator frame fig 8 25 Be sure loose end of terminal lead is not touching ground If lamp lights positive terminal insulation through generator frame is broken down and must be replaced Positive Brush Test for Ground Using a test lamp place one test prod lead on the positive or insulated brush holder and the other lead on ground If lamp lights the brush holder is grounded due to defective insulation at the frame fig 8 26 Repairs Loose Electrical Connections When an open soldered connection of the armature to commutator leads is found during inspection it may be resoldered provided resin flux is used for soldering n a w Fig B 25 Positive Terminal Test for Ground r v 9 t fig 8 26 Positive Brush Test for Ground Caution Acid flux must never be used on electrical connections Turning the Commutator When inspection shows commutator roughness it should be cleaned as follows 1 Turn down commutator in a lathe until it is thoroughly cleaned CAUTION Do not cut beyond section previously turned 2 Undercut insulation between commutator bars CORVAIR SHOP MANUAL