I need some help ... I have reassembled my generator with new bearings , brushes , etc. ... and checked the windings for any shorts .... checked the armature .... but when bench testing it for motoring as I put 6 Volts to it the armature shaft freezes up..... you can not turn it buy hand .... no matter where I rotate the brush plate the armature shaft is locked up ...... HELP .... Joe Gallagher ..email@example.com
Perhaps something like this? Have you checked to make sure the brush holders aren't shorted to ground (except the one that is supposed to be)?
And you have lifted the third brush ?