formed or bent so as to interfere with holding brushes properly against commutator Check brush spring tension as shown in Figure 8 19 Proper spring tension is approximately 28 ounces 4 Check fit of armature shaft in bushing in comrr mtator end frame If bushing is excessively worn the end frame should be replaced and armature checked for damage Check field and field pale shoes for indications of rubbing 5 Inspect armature commutator If rough it must be turned down and insulation undercut Inspect solder at points where armature wires fasten to ends of commutator riser bars to make sure solder is in place so as to assure a good connection See Repairs r Testing Generator Parts Use a test lamp capable of detecting high resistance grounds Armature Test for Shorts Check armature for shorts by placing on growler and with hack saw blade over armature core rotate armature fig 8 20 If saw blade vibrates armature or commutator is shorted Recheck after cleaning between the commutator bars and if saw blade still vibrates armature is shorted and must be replaced x t r b e o v 5 Fig 8 20 Armature Test for Shorts Armature Test for Ground r Using test lamp place one test prod lead on armature core and other on each commutator bar fig 8 21 If lamp lights armature is grounded and must be replaced Armature Test for Open Circuit Check the armature for open circuits by making a bar to bar check as shown in Figure 8 22 Inconsistent variations in reading indicate an open armature f Va 11 y