Choke Coils

[Lineman]

I am making a woodworking dust control station using a squirrel blower off of an old furnace (1/4 horse). I need to slow down the fan output without raising the amperage. I have learned that I can use a resistor coil (also called a choke coil) to lower the voltage and the amperage. These coils were common on equipment in the 1960's. Can these still be found and if so what size would I use? EV

 

[schmitt trigger]

The modern way would be to use a Triac-based lamp dimmer.

The only caveat is, if your motor is equipped with a centrifugal start switch, the minimum RPM should be above the switch's dropout speed.

 

[dr pepper]

If your using a squirrel cage motor then a resistance isnt really the way to go, as this type of motor is semi-synchronous.
Because the load is constant you might be able to get it to work if you start the motor on full then switch to resistance.
What you really need is a variable frequency drive.

 

[shortbus=]

The modern way would be to use a Triac-based lamp dimmer.

Will that work with an induction motor? Induction or the newer BLDC motors are the only two type I know of that are used for furnace blowers.

If your using a squirrel cage motor then a resistance isnt really the way to go, as this type of motor is semi-synchronous.

Think your confusing squirrel cage blower with the squirrel cage rotor in an induction motor.

 

[dr pepper]

Yes shortbus you could be right there.
Squirrel cage blower isnt a term I've heard of, and I've been an industrial leccy for a while.
To me its a tangential or axial blower, they are popular for cooling drives & the like.

 

[crutschow]

A controller like this may work for you.

 

[shortbus=]

To me its a tangential or axial blower, they are popular for cooling drives & the like.

Must be another one of those mother land colony things. While what your calling them is probably the technical names, most of my life I've and everyone I know calls them a 'squirrel cage blower'. Because of the resemblance to a squirrel exercise wheel in a cage. Don't know why they aren't called a gerbil cage blower, cause not many have pet squirrels any more.

 

[shortbus=]

A controller like this may work for you.

Only if the motor has brushes, which is something I've never seen on a furnace blower motor. That is just a repurposed router speed controller.