Shop fume extraction

[Matt Mattingley]

I’m looking for ideas. I want to have dedicated extraction for fumes to the outside (similar to a bathroom fan with about 350-500 CFM. I want variable speed so I elected to go with a three phase 1hp motor and a VFD. The original motor was a 1/3 hp 3460 RPM. The motor I’m using is a 1725 RPM. What are the thoughts are running this double speed? If need be.

I’ve also been given good advice using b-vent for recovery.


I’m intending to use this in my soldering and welding area where a little bit of grinding smoke happens to be.

[Mike Heidrick]

Id not run a 4 pole motor at 120hz for extended periods of time if that is your plan.

[Chris A Lawrence]

I use one of those 6 inch inline duct fans for hydroponic greenhouses for my basement brewery with a cheap router speed control from harbor freight. It works great and I can turn it down to 0 rpm's. The fan runs on 120v.

[Greg R Bradley]

Id not run a 4 pole motor at 120hz for extended periods of time if that is your plan.

I agree and would limit that to 20 minutes unless the motor is in the airstream. They do make units designed for this but they are expensive.

[Tom Bender]

The motor was designed for a given rpm. Spinning it faster may cause the windings, bearings, etc to fail. Running faster or slower may impair cooling and internal overload protection.

You can try it but make sure a failure doesn't create a fire hazard.