How might I regulate (slow down) an A.C. blower motor ???
tommy
Posts: 84
I placed this here, as a blower motor is a "sensor" on the output side...
I'm using a couple of SX-28's (and maybe a Propeller if I don't find a new SX-key pretty soon) to operate a (work-in-progress) hot air solar heat project at my sun-drenched cabin, high in the Colorado mountains... On the input side most of the sensors will be thermistors...
...but on the output side I'd like several variable speed blowers to correctly direct the hot air. "Full On" (and off) is not acceptable. Home Depot sells a $60, 8" blower motor, and I'd like to make it (them) variable.
I found a You-Tube demo of an air conditioner unit blower motor being checked-for-continuity, and it indicated:
--- white to black = high speed --- the man measured 3 ohms
--- white to blue = medium speed --- the man measured 7 ohms
--- white to red = slow speed --- the man measured 8.5 ohms.
So I added (inside a metal electrical box - forest fires here, are greatly frowned upon) - a Radio Shack 8 ohm 20-watt wire-wound resistor in series to a cheap fan I already had blowing on my wood stove (I'd like to slow that down, too).
--- nothing different happened. The fan seemed (by ear) to be moving at the very same speed, with or without the resistor in series. The metal enclosure laughed at me when I removed it's cover, as the resistor was not damaged, measured the same (17 ohm) value before and after, and didn't get even a little bit warm.
I am out of things to try (other than DC blower motors, of which my only experience is those tiny ones used to cool computers).
My experimental 3-speed fan, had the same color wires going into the little motor as the big one did on the You-Tube video; I had assumed to separate coils, but after watching the video thought they might connect to internal resistors.
So I ask: How might I regulate the speed of an A.C. motor ???
thank you,
tommy
I'm using a couple of SX-28's (and maybe a Propeller if I don't find a new SX-key pretty soon) to operate a (work-in-progress) hot air solar heat project at my sun-drenched cabin, high in the Colorado mountains... On the input side most of the sensors will be thermistors...
...but on the output side I'd like several variable speed blowers to correctly direct the hot air. "Full On" (and off) is not acceptable. Home Depot sells a $60, 8" blower motor, and I'd like to make it (them) variable.
I found a You-Tube demo of an air conditioner unit blower motor being checked-for-continuity, and it indicated:
--- white to black = high speed --- the man measured 3 ohms
--- white to blue = medium speed --- the man measured 7 ohms
--- white to red = slow speed --- the man measured 8.5 ohms.
So I added (inside a metal electrical box - forest fires here, are greatly frowned upon) - a Radio Shack 8 ohm 20-watt wire-wound resistor in series to a cheap fan I already had blowing on my wood stove (I'd like to slow that down, too).
--- nothing different happened. The fan seemed (by ear) to be moving at the very same speed, with or without the resistor in series. The metal enclosure laughed at me when I removed it's cover, as the resistor was not damaged, measured the same (17 ohm) value before and after, and didn't get even a little bit warm.
I am out of things to try (other than DC blower motors, of which my only experience is those tiny ones used to cool computers).
My experimental 3-speed fan, had the same color wires going into the little motor as the big one did on the You-Tube video; I had assumed to separate coils, but after watching the video thought they might connect to internal resistors.
So I ask: How might I regulate the speed of an A.C. motor ???
thank you,
tommy
Comments
-Phil
Your link convinced me that fan-speed is built into the windings: the choice of the windings control the speed, and that there are no further adjustments I could make (adding a part here or there) to slow it down any more. The fella in the You-Tube video I mentioned, failed to note that the extra branch he was pointing to, was another, internal motor winding... He was measuring small resitances only to prove it wasn't broken. I shall do no more hacking of working fans, here in the cabin...
...but Leon -- a further google search (speed control AC fans) - led me to some finished products - "SmartFan AC-VX" is one - that did indeed, mention the word, "triac" in the literature. of the four actual products mentioned, one seemed to fit the bill most admirably - controlled by a zero to five volt source, and able to control up to 8 amps. It wasn't a store as such, and didn't give a price - but let me search around a bit today.
I'll peek back here in case anyone else might have ideas...
and I still need an SX-key !!! - I lost mine in the move to Colorado. The powers that be (Ken Gracey, Guenther) have been saying, "soon" since October - and I will continue to be very patient. It's lack is forcing me to learn the Propeller more quickly, which is coming along very nicely - but I have to forget everything I knew about every other assembly language. The clever rascals have made quite a nifty new toy !!! though it's too expensive for tiny 'gadget' projects.
tommy
I still use the SX processors for some projects but not as much anymore and may have a spare SX-key and SX boards I could part with. If you still need one just send me a PM with what you're looking for and I may be able to help. I had a lot for the SX48 and even have some tiny PCB's to mount them.
Best Regards,
Robert