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Dimmer switch motor control?

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#1 overkill



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Posted 21 March 2005 - 10:42 PM

I just made a motor control for my dremel by running a heavy duty extension cord to a 2-gang box. I then put a dimmer switch connected to a plug in outlet in the box. It works great for adjusting speed. But my question to you electrical gurus is, will this damage the dremel in any way? I figured that if you can use it on ceiling fans then you should be able to use it on other things. Also I am going to experiment how well it works on other things like a hot glue gun. Could it work on a lead melting pot? Then you could also melt plastic?

#2 redg8r



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Posted 21 March 2005 - 11:26 PM

It might be ok with your dremel.... I said might.

Ive used them before on smaller motors, the issue is the wattage & load.
Keep the switch itself away from any combustable materials because if anythings gonna fail, itll be the switch burning. Ive burnt a few :?

As far as regulating a high wattage piece like a hotpot, fryer anything that generates good amounts of heat eats alot of wattage & will quickly fry the switch. good thought though, I wish it would work, id have tons of uses for em.

PS. Dremel makes a var speed model, but if it works, it works :D

#3 WaterWerx



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Posted 22 March 2005 - 05:00 AM

Ive heard of people using a similar method with thier dremels, haven't heard of to many issues concerning this, but I don't know how electrical saavy those users were to begin with and how they constructed thiers, this was also on another website unrelated to lurecrafting.

I have a "Dremel" brand footpedal, I don't know how old it is but it was my dad's and he used it with his dremel. When he passed I got it and his dremel along with his other tools.....To be honest I'd give them all back to have him around one more day! (Sorry for getting sappy, there)

Anyways I wish Dremel would bring this item back to market. Even with the MultiSpeed models the foot pedal offers a certain amount of "control" once you get used to using it.

#4 Joe



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Posted 22 March 2005 - 08:30 AM

If you look around at flea markets, you can find footpedals used on sewing machines. They work fine on small motors. Joe

#5 Lock 45

Lock 45

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Posted 28 March 2005 - 08:07 AM


You really want to watchout how much juice you put through that light dimmer switch. Your Dremel will be fine, as would soldering irons, etc. Small low power items are O K to run with these things.

For anything with a large, power sucking, heater element, you REALLY need a Variac. My strong suggestion is to get one rated for at least 15 amps. That way you are covered. That or stay away from any device that draws more than 1,000 watts and go with a 10 amp model. Your rough ballpark matching fudge factor is 100 watts equal 1 amp.

As an example, I run a 1,000 watt floor heater on a 10amp Powerstat variable transformer, which is what these units are called, and have no problems. I run at about 50%. Please keep in mind that one of these transformers can be cranked up to produce 140 volts, so use caution.

Check Ebay for these devices. You can sort of self educate yourself by viewing them.


#6 jm



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Posted 23 June 2005 - 07:49 AM

The dremmel tool is a series wound motor, and it is ideally suited to control by a SCR, (silicon controlled rectifier) which is the working stuff in a dimmer switch. It's actually better for the motor than a resistance type foot control pedal, like from an old sewing machine. The only caveat is that it may unduce back voltages, that destroy the dimmer. That's why most dimmer switches state clearly that it is only for an incadescent (resistance) load. It amounts to a six dollar experiment that usually works just fine.

Induction motors, unless they are specially made, will tend to overheat when slowed down by a dimmer switch. That is because their speed is regulated by the frequency of the power and the winding configuration in the motor, minus shippage. (A 1725 rpm motor is really 1800 slipping 75 rpm.) A ceiling fan motor is wide, and has a lot of ventillation to help it dissipate the heat of excess slippage.

The way to tell them apart is that an induction motor doesn't have any brushes in it. Induction motors hum, and series motors whine. Drills, vacuum cleaners, hand saws, etc are all series motors. Washing machine motors, refrigerators, table saws are all induction motors.

Hope this helps :)


#7 jm



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Posted 23 June 2005 - 01:09 PM

Lock 45,

Variable transformers work good, but they are heavy. We use triac and scr based controls on very high horsepower motor starters. They are just a tad bigger.

About the only neg about a dimmer is that it can mess up the radio. Wait a minute, I have teenage boys, maybe that's a plus. :twisted:

Here's some links

1200 Watt Lamp/Frying pan dimmer circuit.


600w - 2400 w dimmers (commercial)