The KBIC/KBLC motor controller circuit board which drives my Chester
Conquest mini lathe has died, yet again.
I am fed up with repairing it (and I am usually a patient and repair-y
type guy, I nursed a Hoover washing machine which went wrong at least
once a year for 40 years).
The one I bought is a HHD6-G model, 1200W 220V AC input 0-220V DC 8 Amps
output, whereas the motor on my lathe is 90V DC and rated at 5 Amps.
Bit of a mismatch, but... it is a true speed controller, the speed
doesn't vary with load, and so I put a resistor in series with the pot
in order to prevent high speed, high current, high voltage, high power
situations. It is plenty fast enough.
And - it works, much better than the KBLC did. For normal use the motor
does not seem to be overheating, though later when I upgrade it (when
the reversing switch arrives from China - Chinese stuff can be good and
really cheap, but it takes so damn long to arrive!) I will put a thermal
cutout on it. It has a fuse already.
What's good? The speed doesn't vary with load. At all, it seems, unlike
the KBLC, which would do so noticeably.
More impressive, the improvement in low-speed torque is astounding. I
can't stop the chuck by hand, which I could do with the KBLC.
Thread cutting has gone from just-about-doable-if-it's-small to
(except I wired it up wrong first time round and blew all the fuses and
all the tracks on the input mains filter board - in keeping with the
phrase: measure twice, cut once, we should have: check with a meter for
stupid inattentive mistakes before applying mains for the first time!)