Technical Data

We bought three motors for Anvil Mk1 and turned two of the output shafts down to 9mm with a 3mm keyway to fit our gearboxes. This proved to be a very bad idea as the shafts sheared when placed under heavy load. (ie driving flat out into a curb.)
Anvil Mk2 has new motors with untouched 12mm shafts and 3mm keyways to drive the gearboxes, no problems so far.

If you are going to strip the motors for modification, keep the time that the armature is out of the magnets to a minimum.

The vent holes on the motor casing should be covered with tape to prevent the ingress of swarf and foreign matter into the magnets and windings. We have had no heat problems with covered motors, even on prolonged runs. The large quantities of swarf on the tape that would otherwise have entered the motors is evidence enough for us.

We required 5:1 reduction for our 6" wheels. Tim thought that Karl should build spur gearboxes from scratch or use chains.
With the time frame we had to build Anvil Mk1, these items were the best way to get a drive together quickly. They have performed flawlessly from the beginning, the only minor complaint is that the input socket has a 0.004" runout which may have contributed to the demise of the first set of motors. The flexible coupling in Anvil Mk2 solves this problem.

Tims Bit.

Don't blow your speed controllers up, it costs £15 for 4QD to fix 'em.