What Are They Called

You may have an extra pair of contacts on the Fwd-off-Rev switch intended to reduce the speed in reverse, many Chinese machines do. As I understand it it's because the motor brushes aren't "symmetrical", being slightly offset to favour efficiency and torque in the forward direction (a bit like the spark on a petrol engine's ignition - I had a Bultaco that would run happily backwards, but didn't make as much power, a Very Good Thing when it stalled on a steep climb and fired up and ran as it ran back down again!).
Re the IR comp, if you have to adjust it, turn it up until the motor starts "hunting" under no load, then back off until it runs smoothly checking that a load on the motor doesn't slow it excessively and it should be in the right area.

Dave H. (the other one)
 
What is "hunting", when I was into dirt bikes I wanted a Bultaco but I don't think they were sold in Canada.
 
"Hunting" is when the revs aren't stable, and you get a regular pulsing in the motor RPM - it's caused by the IR compensation being turned up too far to the point where its feedback loop starts oscillating - there's an inevitable lag between the controller sensing a change in load and adjusting for it, so at the right (wrong!) point the lag between matches the motor and spindle inertia and gets "in step" with how fast the controller accelerates the motor, kind of like the occasional but well-timed push on a swing sending your firstborn into the sky... Also how the majority of oscillators work in electronics and clockwork.

What the IR comp should be aimed at is "critical damping" where it can compensate for load changes in a timely fashion, but not cause the instability - at the other end from "hunting" too little IR compensation will see the motor slow excessively with a load applied to the spindle.

The IR compensation function is what makes it difficult to turn the stationary chuck opposite to the selected direction if you stop the spindle by turning the speed to zero without switching off the supply to the motor controller, voltage generated in the motor is seen by the controller as back-emf due to a load and the controller applies a voltage to compensate, resisting the backward movement. Forwards, the generated emf agrees with what it sees as a reduction of load so it reduces the voltage applied - which on e.g. a KBIC controller is already zero, so no change, the chuck's easy to rotate.

Hope that explains, rather than confuses...

Yeah, the Bultaco was great, not a patch on modern dirtbikes though - they're mad, I won't ride 'em :)

Dave H. (the other one)
 
One thing I noticed when I put a load on the chuck with my hand was that the rpm would increase past the initial setting for as long as I had the load by 100 rpm in some cases. Would that indicate the IR was set wrong. By the way I echo what strantor said about your directions thank you very much.
 
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