Motor speed control for small 120V. AC. fans?

[pcrider]

shaded pole motor speed control

I may be asking to much. I'm looking for a simple circuit to control the speed of a couple small AC muffin fans. I've tried lamp dimmers, and they just don't work, they are very eratic and nonlinear.

I've done dozens of searches, and came up with only a few circuits, none of which really looked like they would do the job.

Is there such a thing as a simple (not to expensive) way to do this? I've considered using a 555 timer to create a sort of frequency drive, but I only know the basics. I'm not at all sure a square wave would be suitable to drive an AC motor.

Thanks for reading and I hope you can point me in the right direction.

 

[plusminus]

120v fan controller

What kind of motor is it?
- 3 phase?
- single phase?
- single fase with fase lag capacitor?
- power?

frequency control is the best way.

 

[dsPIC24F]

triac-based variable-speed controls

I may be asking to much. I'm looking for a simple circuit to control the speed of a couple small AC muffin fans. I've tried lamp dimmers, and they just don't work, they are very eratic and nonlinear.

True, lamp dimmer can only be used for resistor type of load, the user manual should have said that.

 

[pcrider]

120v fan speed control

What kind of motor is it?
- 3 phase?
- single phase?
- single fase with fase lag capacitor?
- power?

frequency control is the best way.

Its a single phase, 120 V. muffin fan it has no capacitor. I don't know that much about motor technology, but I'm sure it is just a field winding, with one of those solid looking laminated armatures. What thats called I am not sure.

 

[Genasor]

muffin fan speed control

there:
https://ths.gardenweb.com/forums/load/wiring/msg1116265815118.html
itsunclebill said "Many fans use a shaded pole motor" and he explains they are compatible with triac-based variable-speed controls, and why they can work erraticaly.
I tried and it worked for me.
A triac switches off when the current is zero. So it needs a subtantial current in order to stay on. The voltage control unit I bought is rated for min-max: 40W-160W, I understand that a load less than 40W wont make enough current to keep the triac on.
These cheap voltage control unit are ment to be use with resistive loads (ie. lights), this means it only lacks a snubber for inductive loads (this helps switching off the triac). So I added a R-C accross the triac, it reduces the noise in the fan and allows for very low speed.
Snubber ratings depends on the fan power, mine is a 240V 56W, I've used conservative values: 100ohm 1/2W-0.1µF 400V.

 

[pcrider]

120v motor speed control

there:
https://ths.gardenweb.com/forums/load/wiring/msg1116265815118.html
itsunclebill said "Many fans use a shaded pole motor" and he explains they are compatible with triac-based variable-speed controls, and why they can work erraticaly.
I tried and it worked for me.
A triac switches off when the current is zero. So it needs a subtantial current in order to stay on. The voltage control unit I bought is rated for min-max: 40W-160W, I understand that a load less than 40W wont make enough current to keep the triac on.
These cheap voltage control unit are ment to be use with resistive loads (ie. lights), this means it only lacks a snubber for inductive loads (this helps switching off the triac). So I added a R-C accross the triac, it reduces the noise in the fan and allows for very low speed.
Snubber ratings depends on the fan power, mine is a 240V 56W, I've used conservative values: 100ohm 1/2W-0.1µF 400V.

I'll have to do some checking, but it makes sense to me. I found the specs on the motor, but it doesn't say if its a shaded pole, or not.

5 3/4" 115 VAC FAN
Very low noise. Ball bearing motor. Operates on 115 VAC. 11-40 watts. Removed from service. Various manufacturers. 5-3/4" dia. fan. Size 7 1/2" X 6" x 1 1/2".
SPECIFICATIONS
5 blade fan
240 CFM

Thanks, I'll let you know how it works out.

 

[Jack4343]

120 vac fan speed controller

I have found a very useful, inexpensive, no problem, inductive load, 5 amp, AC fan control for the size motors under discussion. It is a single pole, fully variable rotary speed control from Ace Hardware model 5A-120 AC for ten dollars ($10). It fits inside of a standard electrical box. I have used it on various small motors and have experienced no problems so far. Ace Hardware package, product or skew number is 3027596.
I would appreciate more info about your five bladed 240CFM fan pcrider. I would like to get my hands on a few of those myself.

 

[pcrider]

120v fan control

I have found a very useful, inexpensive, no problem, inductive load, 5 amp, AC fan control for the size motors under discussion. It is a single pole, fully variable rotary speed control from Ace Hardware model 5A-120 AC for ten dollars ($10). It fits inside of a standard electrical box. I have used it on various small motors and have experienced no problems so far. Ace Hardware package, product or skew number is 3027596.
I would appreciate more info about your five bladed 240CFM fan pcrider. I would like to get my hands on a few of those myself.

Thanks for the tip, it sounds perfect for what I am doing, I'll check my local Ace store to see if they have them.

I purchased the fans from Surpluscenter.com, they have a good selection of most types of fans. Here is the direct link to the fans I have.
https://www.surpluscenter.com/item.asp?UID=2007112920395155&item=16-1039

Thanks again, Mike B.

 

[kender]

120v muffin fan

I have found a very useful, inexpensive, no problem, inductive load, 5 amp, AC fan control for the size motors under discussion. It is a single pole, fully variable rotary speed control from Ace Hardware model 5A-120 AC for ten dollars ($10). It fits inside of a standard electrical box. I have used it on various small motors and have experienced no problems so far. Ace Hardware package, product or skew number is 3027596.
I would appreciate more info about your five bladed 240CFM fan pcrider. I would like to get my hands on a few of those myself.

What's the internal makeup and principles of operation of this regulator?
Come to think of it, I can buy on at Ace and do some vivisection.

 

[nandhu015]

variable speed muffin fan

A simple microcontroller either PIC or Atmel can easily solve this.

Search in microcontroller section.

Regards
Nandhu

 

[grittinjames]

how to control muffin fan speed

U CAN USE A SIMPLE RC TRIGGERED TRIAC CIRCUIT ,THIS IS WIDELY USED FOR CEILING FAN SPEED CONTROLL