Can you slow down rotator motors?

DLBFalcon

Junior Member
Anyone know a tip/trick where you can slow down the speed of a fast rotator motor? Why do some motors have capacitors across the + and - terminals and some motors don't? I heard somewhere you can use resistors in series circuit to do this, is that true? I like the slower motors better and can't seem to find any for sale, but I have a bunch of fast motors. Thank you!
 

MtnMan

Senior Member
Yes, a series resistor will work to slow a motor, within limits. The two-speed Federal FireBeam, for example, uses a 9V motor, running on 12-14V, for fast speed. With a 50 Ohm (1 or 2W) resistor in series, the motor voltage drops to about 9V for standard speed. I'm pretty sure all Federal fast rotators use 9V motors.

Other manufacturers (thinking of Code 3) seem to use the same motor, with different worm gears, to produce different speeds. Motors don't like undervoltage, so the combination of a series resistor and high gearing might not work as well.

The capacitors are for EMI reduction.
 
OP
OP
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DLBFalcon

Junior Member
Yes, a series resistor will work to slow a motor, within limits. The two-speed Federal FireBeam, for example, uses a 9V motor, running on 12-14V, for fast speed. With a 50 Ohm (1 or 2W) resistor in series, the motor voltage drops to about 9V for standard speed. I'm pretty sure all Federal fast rotators use 9V motors.

Other manufacturers (thinking of Code 3) seem to use the same motor, with different worm gears, to produce different speeds. Motors don't like undervoltage, so the combination of a series resistor and high gearing might not work as well.

The capacitors are for EMI reduction.
Thank you! I'm trying to find some slow rotators to slow down some D-Tech rotators for a more distinct flash rather than a fast "twinkle". I noticed also the motor shaft on some motors is smaller diameter than other motors so I thought about the worm gears, but can't seem to find the same size diameter to fit unless I'm just looking in the wrong place. I'll try the 50 Ohm resistor and see how that works and do some more looking into finding a different worm gear more. (That's how I found out the hole diameters was different on some gears because I pulled one off a different motor.) I have a FireBeam and wondered how they did the two different speeds! Thank you for the help!
 

bpollard

Member
I have wanted to do this on the Code 3 rotators on the rear of two of our trucks from years. Those beacons spin way too fast. But replacing worm gears is probably easier and more sensible than installing drop-down resistors to reduce voltage to the motors.
 
OP
OP
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DLBFalcon

Junior Member
I have wanted to do this on the Code 3 rotators on the rear of two of our trucks from years. Those beacons spin way too fast. But replacing worm gears is probably easier and more sensible than installing drop-down resistors to reduce voltage to the motors.
I'll try to find gears first, the resistors are just a "back-up" idea.
 

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