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Originally Posted by Joe Ross
I'd suggest going by the electrical rules from 2004.
The reason they didn't use to allow the globe motors to be hooked up to spikes is the spikes are only rated for 20 amps, while the globes draw a little more then that at stall. If you do want to use a spike for the globe motor, make sure the mechanical design is such that you will never stall the globe motor. Better yet, just use a speed controller.
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i definitely agree with joe - you should follow the 2004 guidelines unless you know exactly what your doing.
chances are if you hoked up your globe motor to a spike it would work perfectly, and you wouldn't worry about it until it stalled. when a motor stalls, or stops turning while power is still applied, it draws the most current (thus cheap motors are rated at the no-load current and nice motors are rated at the stall current) possible thorough its windings. as previously stated, the globe motor stalls at slightly above 20 amps.
without bringing the engineering team to tears, it is very hard to stall a motor in the shop, but incredibly easy to stall it in the heat of the competition. testing the electronics extensively before the bot ships is very important, because if the motor stalls for the first time in competition, the 20 amp
automotive fuse (not the breaker) will probably blow. this will leave your robot motor-less and probably in bad shape. then you will have to spend time in the pits riping your bot apart to replace the fuse (this happened to us 2 years ago). we didn't bring any extras so we had to send people out to find an auto shop... i think you get the picture
so unless your
sure that the motor will never stall, or you have a 15 amp breaker on the circuit, don't use the spike -- its possible, but a bad idea.