VFD for blower speed controller

[lakerd]

I am thinking of splurging for a variable frequency drive for my blower moter. the rheostats i have tried don't slow it down enough for my liking. my understanding of VFD is that it won't harm the motor at low speeds. does anyone have experience with these on a shaded pole ac motor and advice or recommendations?

 

[Mech e]

You need a triac or FET based controller, not a rheostat. These controllers lop off part of the sine wave to vary motor speed.

 

[fbelec]

also some motors make more hum on a rheostat

 

[brenndatomu]

What's this on?
We have been automatically controlling the speed on our wood furnace blowers using head pressure controllers for 3-4 years now...they are made for AC units, but work great for our hack too...can be bought reasonably also.
Click the link in my signature line, it will get you to the info...or just use the site search feature.

 

[lakerd]

so i plugged one rheostat into the wall and another rheostat into the first one and the blower into the last one and it slows it down a bit more. anyone tried that before?

 

[fbelec]

if it is not labeled motor controller you will over time burn up the motor. if it is a dimmer this is what will happen and or you will blow the dimmers one or both

 

[fbelec]

a vfo the motor will last as long as it was designed to

 

[DBoon]

VFDs produce pulse-width modulated outputs with some very high harmonic frequencies that will stress the motor insulation in a much different way than a standard 60 Hz output. Therefore, motors designed to work with VFDs have different types of insulation systems than motors designed to work on pure 60 Hz inputs. Initially, the motor will work, but may fail with extended use with a VFD. Generally, AC induction motors designed for use with VFDs cost more, and I doubt that any motor used with a woodstove blower is designed for use with VFDs.