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Unread 03-01-2007, 09:00
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FRC #0088 (TJ2)
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Re: Fisher Price Motor Replacement Gearbox

Quote:
Originally Posted by Gdeaver View Post
I remember last season there were a couple of posts concerning these gear boxes and mounting the fisher price motor directly to the housing cutting off the air flow of the motor causing over heating. Is this still an issue. Is there enough shaft Length to allow use of spacers? You got let those can motors breathe.
Yes it is true that airflow can be the difference between a motor and a toaster. The FP motors are especially problematic because they have so much power in such a small package.

For the most part, my experience is that you will be fine with blocked air holes on the front of the motor if you design your motor to work on the left half of the speed/torque curve (and preferably on the left 1/3). But if this is not possible then you will need the flow from the front of the motor.

This is pretty easy to accomplish with simple washers or spacers because the FP motor shaft has to be shortened in order to fit with the gearbox -- all you have to do is keep the shaft a bit longer and then space the motor back a bit from the gearbox.

Joe
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