What size pulley would I need?

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Subject: Help
Name: Chris
Who are you: Other

If I have a motor that's spinning at 950 RPM's with a pulley that's 6in diameter with a belt running to a generator, What size pulley would I need on the generator to make it spin at 3600 RPM

Hi Chris,

The circumference C of a circle is given by

C = 2 π r

Thus in 1 minute your motor has completed 950 revolutions and the belt has moved

950 (2 π 6) inches.

pully

Suppose that the smaller pulley has radius r inches. Thus in 1 minute the smaller pulley has completed 3600 revolutions and the belt has moved

3600 (2 π r) inches.

If there is no slippage in the belt then

950 (2 π 6) = 3600 (2 π r)

6 950 = r 3600 or
r = 6 950/3600 = 1.58 inches

Penny

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