Single phase VFD

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hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Has anyone out there installed a VFD for 120 volt single phase ceiling fans, I think they are shaded pole motors, so they should be controllable. I tried talking this church into three phase fans, but to save money they installed single phase fans with a listed rotary fan controller, the problem is, when the fans are slowed down they make a very loud humming that drowns out the preacher. ( Hard to sleep too!) Will a VFD be any quieter? There are six fans are at 24' AFF.
 
I didn't wire them, when they wanted to take the cheap way out, I passed on it because I did not want my name and reputation tagged on it and now of course I have to fix it! They are using one control for all six fans, and it is rated for the total load from the info they gave me over the phone. The fans are not all that big, looked to be 52". From the sound that they are making, the controller appears to be an SCR, pulsing the power to the fans. I figure a VFD would be smoother in output at lower speeds. I've never used one though for a single phase motor though, so I don't know how well it would work.
 
The literature for those drives say its not intended for single phase motors, also the output is 230 volt three phase. I need 120 single phase, I would think a stepdown transformer would not like the output of the drive,or would I be able to use the input neutral with the output? Good prices on the drives though, I just wish they had went with the Big Ass fans like I wanted to. (Of course we would have to remove the name stickers!) I have 120/240 volt three phase delta service, so three phase fans would have been no problem.
 
I always hate it when the costumer goes cheap and it comes back to haunt you with issues that would not have been if they had just done the job right to start with.
What brand fans did they go with (Hampton Bay) ? I wonder if the answer is just to bite the bullet and get new fans.
 
acrwc10 said:
I always hate it when the costumer goes cheap and it comes back to haunt you with issues that would not have been if they had just done the job right to start with.
What brand fans did they go with (Hampton Bay) ? I wonder if the answer is just to bite the bullet and get new fans.
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How did you guess? That was a no brainer wasn't it. They hired a member of the congregation who was out of work to install them (definitely not licensed) I have not looked at how he has wired them yet, since they haven't went up in smoke yet, he must have missed the high leg in the panel!
 
hillbilly1 said:
How did you guess? That was a no brainer wasn't it. They hired a member of the congregation who was out of work to install them (definitely not licensed) I have not looked at how he has wired them yet, since they haven't went up in smoke yet, he must have missed the high leg in the panel!
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Or when he fried one or all of the fans he put them back in the box and returned them. To the big orange. :D
 
hillbilly1 said:
They are using one control for all six fans, and it is rated for the total load from the info they gave me over the phone.
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I would be willing to bet it is a bad controller. Or even if it is rated for the 6 fans. It will not carry the load efficently.
I have bought controllers that I sware we're just a light dimmer wrapped in a fan box. And of course they fan would be loud and I would have to change it.

You should try a new controller. If possible split them up to more then one controller. You may be able to use remotes for each fan.
 
I haven't checked yet, but I believe he daisy chained all of them, then went down to the electrical room where he put the speed control. Would have to get a scissor lift back out there to split them up, plus its all in MC cable, so there would have to be some piping run too. Trying not to invest too much more of my time in this than I have to. (One of those freebie jobs)
 
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