I have designed a geared arrangement (I take any opportunity to make gears!) that uses one knob to turn the two pots in proper sequence, just haven’t gotten around to making it yet. The for/rev issue, I use a relay to swap the outer two pot wires on the armature control pot so that the drive is at identical speed but in reverse. The brake issue, I have a timer relay to hold the brake on until the spindle stops, and then it disengages the drive’s run command so the drive is in neutral. The Parkers have two annoying features, the direction is controlled by the RPM knob, rather than a forward/reverse setting and a speed control separate, and dynamic braking is 0 rpm setting, so when you set 0 rpm to brake spindle, it fights you turning spindle by hand to measure, inspect etc.
The only disadvantage to this setup is when the field is weakened the dynamic braking is weakened too. Field goes to full, then armature goes to zero.
EUROTHERM ITOOLS DEFAULT PASSWORD FULL
Turn first pot full clockwise, armature is full voltage, move hand to next pot, start turning it clockwise, field goes down to full RPM, 4000 on mine. I have the two pots next to each other wired so that with pots full counterclockwise the armature is zero, field is full.
I did say "nuisance"? MG-era "large frame" 3 HP motor is "straight shunt", doesn't have that winding. Just hardwire it to favour forward running. If reverse is use primarily for unloaded rapiding, then BFD. If reverse is used a lot for cutting - such as threading AWAY from shoulders - leaving it simply "hard-wired" causes higher loads to REDUCE power and DROP RPM instead of trying to hold it up. Near-zero effect at light loading,even if wired bass-ackwards to favour reverse. it will work either way you wire it up.It is HIGHLY current-flow dependent for strength, so exhibits a very "load related" touch. (not sure why, maybe the motor gurus can explain) i believe i have currently connected but would have to check to be sure.
EUROTHERM ITOOLS DEFAULT PASSWORD SERIES
I've run the motor with and without the series field and honestly don't find a big difference in performance. The series field S1 and S2 are in series with the motor armature.
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