inexpensive variable speed controller(but will it work)

rocketmann

rocketmann

Joined
Dec 24, 2005
Messages
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I just recieved a flyer from HF today and they are listing a router speed controler, item# 43060-2hmb. It claims to be good for any ac/dc brush type motor up to 15 amps.. Would this work for a grinder?:eek:
 
Don't waste yer money. I have one and it is totally useless for this purpose.

It does regulate RPMs on some motors, but takes all of the torque
out.
 
These controls just limit the voltage to the motor (like a dimmer switch to your lights). Nice idea and all, but the energy drop of lowering the voltage takes all of the "oopmph" out of your motor. The "proper" way to run a motor at variable speed (AC anyways, don't know about DC) is to vary the frequency of the electricity coming into the motor. For example, if you have a 1725RPM motor rated to run at 120v 60Hz (standard wall power), a "variable frequency drive" unit (that's the buzzword you want to remember) will send the motor a full 120v, but remodulate it to say, 30Hz to slow it down. Consequently, you can up the frequency as well and overdrive the motor. I've seen VFD kits advertizing a 4x speed increase in a motor (ie. 1725RPM motor can go to 6900RPM).

Problem is that they aren't cheap. A decent VFD will set you back a few hundred $$.

-d
 
what is a split phase motor? I saw one on ebay and I'm not sure what that means, it claims to be 115 v..
 
rocketmann said:
what is a split phase motor? I saw one on ebay and I'm not sure what that means, it claims to be 115 v..
Click to expand...

One that one I'm clueless. Sorry :)

-d
 
rocketmann said:
what is a split phase motor? I saw one on ebay and I'm not sure what that means, it claims to be 115 v..
Click to expand...
Generally, "split phase" refers to how the motor starts. A "split phase" motor has a main winding and "starter" winding. The input power is "split" to the the two windings. The windings are unlike which causes a phase displacement between their fields thus producing a rotating field.
Here is a little reading on them: http://ourworld.compuserve.com/homepages/boyce_smith/split-ph.htm
Regards,
Greg
 
Believe me, if there was an easy inexpensive way to make variable speed we'd all have it by now. All these things have been tried by someone in the past and found wanting. Some have toasted users motors.:eek:

The control featured in this thread is for fractional HP motors, like dremels, foredoms and such.
 
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