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Unread 21-12-2005, 07:26
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Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
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Re: Cheapest and easiest way to slow down a motor

Quote:
Originally Posted by Don Rotolo

2. To control the speed to any value, and not lose torque or power, use a PWM motor controller in "Locked Anti-phase" mode. Victors (at leats 2005 version) don't do this, but something like that should be easily findable, try a google search or visit IFI and other robotics sited.
Don,
Victors are in "locked antiphase" operation. They are a classic "H" bridge with one input signal representing both magnitude and direction. You could set the input signal to switch direction as rapidly as the PWM allows but the current draw is significant. Since that is not needed in most of our applications, you won't see it very often.

Sandrag,
your 555 circuit is an excellent method, just be sure that the MOSFET can handle the current for you motor. The spec sheet for the device shown says it is good for 50 amps if it is at 25 degrees C. It might need heatsink but any chunk of aluminum should work if it is insulated.
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Al
WB9UVJ
www.wildstang.org
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