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Looking for any motor swap ideas.

Looking for any motor swap ideas.

Looking for any motor swap ideas.

We have this motor:

Which is found here:
3LU88 @ Grainger

It's a Permanent Split Capacitor motor with a 48YZ frame. It's four speed. Each speed is 150RPM less than the next, starting at 1075RPM.

The problem is that the slowest speed 1075-(4x150)= 475RPM is still too fast as it blows everyone's hair about while they're trying to sleep.

We'd love to replace this with a 3PH motor that we run with a VFD but we can't find anything close to it.

We still need to run it pretty fast when A/C is happening or we'll get evaporator icing (disaster). Any suggestions?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Looking for any motor swap ideas.

Recent (10 yrs or so) air handlers for houses have available high efficiency variable speed drives.
The rest of the air handler looks normal. The motor is a 3ph, driven by a custom 220/1ph in VSD built on/in the motor shell, that somehow senses the load on the fan, just by looking at current waveforms, and runs QUIET. There is no 'fan speed' input; it just uses a normal thermostat.
The technology is covered by current patents, so you can't buy the motor at Grainger.

Last time I tried to replace just the motor (just the controller really), the best quote was $975, which was the trade retail price of the entire air handler with the magic motor, plus $350 to remove the motor, plus shipping. I bought the entire air handler, installed, from a local outfit that did a good job, including a new condenser unit, and I think cleaning of the ducts.

I also love the programmable thermostat that we bought separately, because you can control the setting by time of day with an hour of resolution, and it has home and away settings, and a default setup that works pretty well to save energy. ... and I hate it because it runs completely on two AA cells, which last several months, but not most of a year.

Mike Halloran
Pembroke Pines, FL, USA

RE: Looking for any motor swap ideas.

Since it’s a PSC, you can use a single phase output VFD on it. They aren’t cheap, but likely less than replacing the motor and adding a 3 phase VFD. There are only a few brands available and several of them are the same product brand-labeled. The real mfr of those is called Invertek, based out of the UK. But they sell under the names Bardac and Anacon here in the US as well. There are a couple of open board style VFDs available here sold for OEM fan mfgrs but you have the skill set necessary to properly package them. Can’t remember the names right now, but I have a list somewhere and I’ll look for it if you can’t find it on the Google. The problem there is if you search for “single phase VFD” you get 10 million hits on 3 phase VFDs that accept single phase input, not single phase output.

PS: thought of one of them, Stratus drive. http://controlresources.com/variable-frequency-dri...

" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Looking for any motor swap ideas.

Hi Mike. Thanks for that. In this case I have to be able to control the blower for various reasons so it's not allowed to have any kind of 'mind of its own'. LOL.

Jeff; Thanks. I hadn't come to grips with a 1ph VFD and yes you get completely screwed-over by brainless search engines hunting in that arena. With those links I think I have my solution!

Keith Cress
kcress - http://www.flaminsystems.com

RE: Looking for any motor swap ideas.

Which one are you going to try? I'll be interested in your experience with it either way. I've used the Invertek one in the past, but never the Stratus.

Here's the other one I had on my list. Never used this one either.

" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Looking for any motor swap ideas.

I'll run these by the end user today and see what shakes out.

I like the standard VFD shape/function of the Invertek drives but also like the screw-it-to-the-ceiling functionality of the Stratus', Not real thrilled with Stratus' constant warnings; "For use with inverter duty motors", since no one on earth probably makes an 'inverter duty' single phase motor. They also recommend something like 40" motor side cable or less!!! I can probably do that in the application but I'll have to look.

Down side on the Stratus is paying $180 for the drive but needing the $290 hand-held to program it.

Ohh. Actually liking the Varidrive a lot. Can't find pricing on it or the Invertek. I'll check them out when I get the chance. I'll let you know what transpires including postponing this until next winter's service since I'm pretty overwhelmed at the moment getting the rest of the punch list done before the car pulls out of the yard.

Keith Cress
kcress - http://www.flaminsystems.com

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