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+-- Thread: Motor Speed Reduction (/showthread.php?tid=7351249)
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Motor Speed Reduction - Willyou - 11-14-2019
I have a small electric heater in my shop that has a approx. 8" fan driven by a small 120v motor; one of those small (prob 1/8 hp) open units (no case around it). The motor is one I salvaged from a home gas furnace. It had a squirrel cage fan on it and it was for assisting exhaust of flue gasses; somewhat like a bathroom exhaust fan. As mounted in the heater, it rotates faster than I would like and blows air over the heating coils too fast. I don't know the actual rpm. Would this adequately and safely slow it down?
RE: Motor Speed Reduction - Stwood_ - 11-14-2019
I don't see why it wouldn't work. I was going to suggest a wall mounted light/fan dimmer.
RE: Motor Speed Reduction - Willyou - 11-14-2019
(11-14-2019, 06:07 PM)Stwood_ Wrote: I don't see why it wouldn't work. I was going to suggest a wall mounted light/fan dimmer.
I did a little web searching before posting and found some cautions about using a dimmer. The caution regarded over heating of both motor and dimmer. However, I think they were referring to larger motors. I don't know if it matters or not.
Thanks
RE: Motor Speed Reduction - Stwood_ - 11-14-2019
I use a normal wall dimmer on a 4' (helicoptor size
) ceiling fan in the shop. It's been hooked up since 2007.
RE: Motor Speed Reduction - Willyou - 11-14-2019
(11-14-2019, 06:48 PM)Stwood_ Wrote: I use a normal wall dimmer on a 4' (helicoptor size
I know what you are talking about. I only know what I've read. Apparently, ceiling fan motors are specifically wired to use the dimmers. Not all motors are.
Thanks
RE: Motor Speed Reduction - jasfrank - 11-14-2019
Universal motors, and ac/dc motors can be controlled with a dimmer or rheostat. DC motors with a controller.
RE: Motor Speed Reduction - Roly - 11-15-2019
(11-14-2019, 03:35 PM)Willyou Wrote: I have a small electric heater in my shop that has a approx. 8" fan driven by a small 120v motor; one of those small (prob 1/8 hp) open units (no case around it). The motor is one I salvaged from a home gas furnace. It had a squirrel cage fan on it and it was for assisting exhaust of flue gasses; somewhat like a bathroom exhaust fan. As mounted in the heater, it rotates faster than I would like and blows air over the heating coils too fast. I don't know the actual rpm. Would this adequately and safely slow it down?
Can you just restrict the air flow and not worry about the motor speed ? Restricting the air flow on a centrifugal blower will reduce the motors current not increase it. Roly
RE: Motor Speed Reduction - daddo - 11-15-2019
I'm with Roly on this one. Restrict the supply to get what you want.
I don't think that controller is going to do what you want.
RE: Motor Speed Reduction - Willyou - 11-15-2019
(11-15-2019, 10:50 AM)daddo Wrote: I'm with Roly on this one. Restrict the supply to get what you want.
I don't think that controller is going to do what you want.
Sorry. I should have been more clear. The motor no longer has the centrifugal (squirrel cage) blower. It now has an approx. 8" dia axil fan mounted to it. Given the overall configuration of the heater box, I could probably restrict the outflow with a grill of some sort. A controller, if it works, will also quiet it down somewhat which would be a nice additional benefit. Lacking that, I'll do some experimenting with some grill work.
This is the (or similar) motor I'm asking about:
https://www.supplyhouse.com/Fasco-A200-1-Speed-1-30-HP-3000-RPM-Lennox-Inducer-Motor-115V
RE: Motor Speed Reduction - aquaticjim - 11-15-2019
With all this effort, why don't you just purchase a heater with a blower?