Would this work for an old furnace blower motor where the motor runs a belt?  It doesn't have a capacitor start just as said it required.

 

https://www.wolfautomation.com/55ac10e-speed-control-variable-ac-voltage-supply/?gclid=EAIaIQobChMIzK6ezPPA6QIVIgiICR294wrhEAQYAyABEgKdIvD_BwE

 

 

Edited May 19, 20205 yr by HandyDan

Most furnace blowers have multiple speeds. If yours does, a salvaged window fan switch could do the same thing 

31 minutes ago, lew said:

Most furnace blowers have multiple speeds.

It is single speed 1625 RPM.  I was hoping this is variable speed control.

 

 

If you haven't started the build yet, you could probably get a direct drive squirrel cage furnace blower for a couple of bucks. HVAC guys replace furnaces all the time and just junk to old ones. It would make a more compact unit and probably be variable speed.

 

Here's the first one I built. It was later replaced with a slightly smaller one-

 

I took out the tilt out basement window

 

Then made a plywood housing. The frame around the hole supports the filter. If you do something like this, go to the Borg and measure some of the inexpensive furnace filters to get the correct dimensions (don't ask how I know this).

 

The carcass. Air inlet holes on both sides

 

 

The carcass was fastened to a piece of plywood that fit into the basement window opening. The Blue stuff is what I'm using for a filter. What you can't see is the .25" x .25" wire mesh covering the holes. It keeps the blue stuff from being sucked into the blower. The screen isn't necessary if you use premade furnace filters.

 

 

 

The first blower simply exhausted the air to the outside through a hole. One day I powered it up. It didn't spin. I thought it was the starter cap gone bad. When I opened it up, I found a bunny rabbit had crawled through the opening. got wedged and died. So, I added-

 

The cover is pushed open by the force of the air and its weight closes it when the fan turns off.

 

The 4 bolts are what holds the blower the the plywood window filler. The carcass fits over the blower unit and is attached to the plywood window filler with screws.

Edited May 19, 20205 yr by lew

It may well be that your blower is a split phase motor and that controller would work....but that's a guess. Be aware, the capacitor is sometimes located remotely (I have one where the capacitor is located on the outside of the blower housing) and not in a bubble on the motor. If you can look at the motor plate it may have some info as to what type it is.

This is just the "single speed" motor from an old furnace where the motor sat on top of the blower and a belt ran to it.  I just want to use the motor and add variable speed to it.  I threw the blower away.  

 

I have a blower set up similar to Lew's.  Mine is on a track where I can open the window and slide the blower into position and the dust is blown outside.  I use it once a year to clean the shop.  I run it while blowing the dust off of everything and the blower sucks the airborne dust out of the shop and then vacuum the floor.  Basement version of leaf blower cleaning.

2 hours ago, HandyDan said:

Basement version of leaf blower cleaning.

I was wondering what you were doing with the motor you didn't say in your first post.

 

3 hours ago, HandyDan said:

I just want to use the motor and add variable speed to it

Sorry, I misunderstood what you were doing.

Live and learn.  I didn't know these were available.  Maybe @Artie can shed some insight as to how well they would work and if the motors could be used on equipment.

 

Edited May 20, 20205 yr by HandyDan

Roly might have some insight as well, if he catches this.

Dan I think that is a rheostat type switch. They have been promoted as speed controls for routers but it is my understanding that after some use will cause the windings to burn out.Basically it is like starving the motor. Works for incandescent bulbs but not good for motors. Hope Artie can give us some clarification.

1 hour ago, Gerald said:

Dan I think that is a rheostat type switch. They have been promoted as speed controls for routers but it is my understanding that after some use will cause the windings to burn out.Basically it is like starving the motor. Works for incandescent bulbs but not good for motors. Hope Artie can give us some clarification.

I'm thinking a fan motor is different.  The fan resistance keeps them from running right up to speed.  I one time tried to use a regular motor to run a fan and it wouldn't do it.  My 6" metal lathe doesn't need much, 1/4 HP is what is on there now.  I have this fan motor and would like the variable speed.  I am enjoying all the thoughts and replies.  I'm hoping we learn something here.  Might open a new door on variable speed.

A heavy duty (High wattage rating) triac light dimmer might work. They don't function on resistance changes.

 

http://www.factsfacts.com/MyHomeRepair/DimmerSwitch.htm

Kinda red faced here, not really much of a motor electrician. I can order a replacement motor, and replace it, but not up on what controls work on single phase motors. I gotta think online info should be plentiful. I’m pretty inexperienced on VFDs also   

33 minutes ago, Artie said:

Kinda red faced here, not really much of a motor electrician. I can order a replacement motor, and replace it, but not up on what controls work on single phase motors. I gotta think online info should be plentiful. I’m pretty inexperienced on VFDs also   

 

Just my luck.  I'll have to do some more research.

@HandyDan,

 

Post a photo of the lathe, and the motor set up.

A Reeves Drive from a Delta scroll saw might be able to be adapted to it.

Not sure this is what you are looking for , way too much tech stuff for me.

 

Three ways to control a single phase motor

The problems with using a standard type motor with a speed control include heat build up in the motor due to the slower speed not moving enough air through the motor, along with lower HP, and lower torque being developed.

So most times going this route requires the use of a larger HP motor to compensate for the lost HP, and torque.

A Split Phase motor will not work well at all due to the motor not developing enough speed to disengage the start circuit contacts.

Edited May 21, 20205 yr by Larry Buskirk

@HandyDan,

Here's a couple parts that might be rather easy to adapt.

This Reeves Pulley fits a 1/2" motor shaft.

https://www.ebay.com/itm/Delta-Rockwell-24-Scroll-Saw-Variable-Speed-Pulley-40-440-Nice-Condition/303565004841?hash=item46ade26029:g:a7YAAOSw4Ileual6

 

This mounts between the motor and the motor mounting plate, and will provide belt tension adjustment.

https://www.ebay.com/itm/Delta-Rockwell-24-Scroll-Saw-Variable-Speed-Motor-Mount-Bracket/303560730713?hash=item46ada12859:g:C08AAOSwmuhesvzD

 I don't think this type of controller will work for your motor.   I am not a expert on this but for reasons as Larry said the speed the centrifugal switch cuts out is a major concern along with motor cooling.   Something like a VF would be better for control on this type of motor but the centrifugal switch is still a problem.    Roly