Moving the Brush Rigging has a drastic effect on compounding strength. Depending on your Generator size 63, 71, 82GA or larger GB's or B sets an 1/8 of an inch rotation will close to double compounding strength. Against the rotation makes compounding stronger, with the rotation makes it weaker. What it sounds like is the speeds may have been adjusted with a bad Carbon Contact on one of the speed relays IE, E1A etc. The contacts get a glaze on them and have a high ohm value. Car speed will increase if the contact is changed and has a zero ohm value by sometimes 30fpm especially on a self excited main generator field. There are a lot of things to look at on a Ward Leonard closed loop system. Motor Fields, Armature Voltage, Compounding, Load Weighing, and correct switches operating. Have you measured the speeds? What is contract speed and what speeds in both directions are you getting with what voltages on Armature and Fields as to what Motor Nameplate voltages are?
Last edited by Rolly; 08/12/14 03:03 PM.
