Well, the E20 does have a current limiter, however it works as follows:In speeds 1-4, the current limiter does nothing really. However when you go to speeds 5-8 (with field weakening), the armature draws more current under load. Without a control of some sort you could overheat the motor fast on a hill.
To fix this, the E20 has a small circuit that basically compares the current going thru the main shunt to a predetermined value. If the current thru the shunt exceeds that value a transistor turns on and bypasses the entire field weakening circuit by dropping the FW relay. With the FW resistors bypassed, the field gets full power, armature current goes down and the tractor essentially goes to speed 4 (full power).
That might be your problem; in D2 the motor is working pretty hard. Perhaps the card logic is having problems and is causing the field to oscillate back and forth. Does this only happen in high speeds (5-8) or in any speed?
Chris Jeremy Gagliardi com wrote:
On Thu, 29 Apr 2004 12:24:28 -0400, "Perry Cain" wrote:I thought I had the same problem. Seemed to happen in D2. Looked at everything. Actually, it turns out, that when going that speed, the seat was bouncing, turning the seat switch off and on very quickly....That may explain why I've never had that chattering relay problem in D2. On my E20, if the seat switch goes off, even for a fraction of a second, I have to start from throttle "0" before I can go again. It completely resets the system. E20 Bethesda, Md (---------------------------) mailto:Jeremy Gagliardi com http://Jeremy.Gagliardi.com (---------------------------) _______________________________________________ Elec-trak mailing list Elec-trak cosmos phy tufts edu https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak