120V, 1HP motor control

[kwired]

What is purpose of this fan?

Was initially led to think it was for exhausting attic, but those typically are thermostat controlled and/or humidity controlled and often would not be running overnight. They also are not typically the type of fan linked by OP. That type of fan would be rare on dwellings, even multi family unless it is providing common fresh air to multiple units or something of that nature.

 

[Todd0x1]

A shareholder of a multi-family building in the penthouse was complaining about the noise of rooftop exhaust fans when they sleep. We are proposing on putting vibration isolation and also adjusting the speed of the fan during night time to further reduce noise. I think a VFD with 3-phase motor is a simpler solution than a multispeed fan.

Could the fan get mounted up on a pedestal, perhaps over a common area, on vibration isolation mounts, and ducted to where the fan used to be?

 

[MidAtlanticMan]

Thanks everyone for the help and suggestions

I wonder if the whine will be noticeable from the apartment below, we will do trial and error with the carrier frequency

Our drives all have high carrier frequencies to ensure quiet operation. Our V3 series (LINK) is likely the most relevant to you but we could likely also use one of our E3 series (LINK) just as easily and at a lower cost. I you'd like to continue using a single phase motor, it would have to be an E3 but I don't think that would be a problem any way.

 

[Knightryder12]

Wow, things are really different where I am at. Down here in Florida, if its a mechanical piece of equipment, then the mechanical engineer specifies the VFD. At least the last three MEP firms that I have worked for, that's the way it is.