home made shop air cleaner motor

[iwirehouses]

Hey I'm in the process of building a air cleaner for my shop to circulate the air. I bought a really nice squirrel cage blower from an old furnace for 10 bucks. This thing is huge, and would probably be more adequate for a shop 3 times the size of mine. Should work Really good in my garage. Anyways, I was toying with the idea of using a cieling fan control on the motor to get different speeds, but I assume it will probably damage the motor. Am I right? Anyway to get different speeds?

 

[LarryFine]

Anyway to get different speeds?

Hey!* :smile:

Most HVAC motors are 3- or 4-speed units, and the speed for cooling (usually faster) and heating (usually slower) are set by the installer. Look for a label on the motor for speed selection.

Typically, you'll find a white wire (to supply grounded condcutor) and several colors, such as black, blue, red, yellow, just about anything. There is probably also a capacitor, which needs to stay.

Now you just need to find a suitable switch. For two speeds, as SPDT switch, such as a typical 3-way light switch, works. For three or more speeds, you'll need a rotary switch, SP3T or SP4T.



Added: Years ago (okay, many years ago; 2nd grade, I think), the word 'hey' was excluded by my teacher in a how-many-words-can-you-find contest, using "Merry Christmas" as the letter source. I still won, though.

 

[jmd445]

Generally if the fan is direct drive there will several wires as mentioned before.
Black-Hi
Yellow-Med High
Blue-Med Low
Red-Low

Also, you will need to add some form of back pressure to the fan if you don't have ductwork connected. Example, if you are just going to bolt this to an outside wall, paritally block the fan discharge otherwise the fan will cavitate. You can hear the difference of the fan motor and check the current draw of the motor as you move a piece of sheet metal across the opening. Adjust this for optimum performance.

Jim

 

[iwirehouses]

No this is a simple old blower. definitly one speed. its got almost a 6 amp 110 volt motor with a belt that connects the motor to the blower. This thing really moves air. I can't use a cieling fan "dimmer" to change the speed, can I? I believe it will probably do damage but am not sure.

 

[K8MHZ]

No this is a simple old blower. definitly one speed. its got almost a 6 amp 110 volt motor with a belt that connects the motor to the blower. This thing really moves air. I can't use a cieling fan "dimmer" to change the speed, can I? I believe it will probably do damage but am not sure.

If the motor is inductive (only for AC) and you reduce the voltage and keep the frequency the same the motor will over heat and become damaged. If the motor is AC / DC like some drill motors, you can change the speed simply by reducing the voltage. An inductive AC motor requires a variable frequency drive to change speeds without overheating the motor.

 

[GeorgeB]

If the motor is inductive (only for AC) and you reduce the voltage and keep the frequency the same the motor will over heat and become damaged. An inductive AC motor requires a variable frequency drive to change speeds without overheating the motor.

And you cannot go far with single phase because the centrifugal switch will get in your way. BUT, you might not need to go far.