KB Electronics 8811007 Solid State Variable Speed AC Electric Motor Control, 6.0 Max amp, 115V, # K177-1006

I'm a licensed engineer. I have an attic-style fan that I installed to circulate warm air from my utility room to the living spaces rather than letting that heat it escape through the attic by conduction. To accomplish this, I set the fan up with a thermostat control to turn on above 90F, which keeps the utility room pleasantly warm and dry while also re-circulating the excess heat. The problem was that the fan was way too fast and too loud in the adjacent living spaces when it kicked on. I needed something to slow down the fan, which was a low wattage AC fan with a permanent capacitor across the line (little round guy on the power cord going to the motor). You can't use a dimer switch for this sort of application because it will burn up, and many fan controllers intended for ceiling fans won't work either because they have fixed detents for replicating industry standard speeds at low/medium/high. By contrast, this controller uses a solid-state component called a Triac to give you much more precise continuous control over the fan speed. Using this controller, I was able to lower the fan to a much slower speed than the standardized fan controls, allowing me to get the right balance of comfortable warm airflow and quiet noise levels. When doing this, it is important to realize that AC motors can stall if the voltage is lowered too much, and that they will burn up in place if they stall with power on. These motors need the airflow to keep themselves cool while running. This control has a fine adjustment for setting for the minimum fan speed, which prevents someone from accidentally stalling the motor with the knob alone. This minimum speed adjustment was essential for me to achieve the desired effect in my home while preventing the fan from lowering below stall speed. Overall, this controller allowed me to fine-tune my attic-style fan safely and make my home much more comfortable in the winter while saving me money on heating bills and reducing the heat level in my utility room.

Works so far. I was able to adjust it down to having it almost not be able to run the exhaust fan. Sadly the fan makes a lot of noise (seems angry) when it's barely running so I adjusted it to run at 50% at the lowest. I notice other commenters remarking that they can't get it to go low enough, make sure the Amperage of the version you buy fits the application. I got the 2.5 amp for something that will at most take 1 amp. So it worked pretty well. Documentation is meant for electricians it seems, but I figured it out.

UPDATE0 first one only lasted two hrs when I adjusted the stall screw it just sizzled. 2nd one screw adjustment works just fine, but now my motor has a small hun, not bad, but I can hear it. First one was dead quiet till the adjustment sizzled out, But I still recommend these. Now matter how good a product is, there are bound to be a few defects. First off I had people telling me I could not use this on a Holmes window fan. Well I am glad they were wrong and I was right. This little baby works perfect, no noise, no heat and looks good. I even checked my fan motor for an increase in temperature, guess what, nope. And no funny motor noises as with most other speed control switches on the market. Simple and easy wiring. No adjustments were needed on the speed screw stall adjustment. I think everyone I spoke with said I would only get a max down to 70% some said 50% speed. Well I can go as low as I want with no ill effects. Most importantly doing that with no noise or heat issues is a huge bonus. So now my entry level Holmes fan with this controller is better than their most expensive so called adjustable fan. Cant say enough good things about this controller. If your wondering should you get this or something else, just get it.

This speed control installs as if it were a simple switch in the hot wire line, plus a ground. That makes it easy to install ... make certain the breaker is off and no AC is present. Cut or unfasten the hot line to the original switch (probably a pull chain ... I did this in the fan switch box) and run a two conductor plus ground cable to where you want the speed control. Install a heat resistant box (the control does get warm, not hot) Connect the two insulated cable wires to the two wires on the motor control and connect the bare ground. Splice the other ends into the original switch hot wire that you cut. Do this in a junction box. I was able to squeeze these "fan side" connections (including ground) into the existing box that holds the pull chain switch. I set the pull chain switch for "high" (it has high, low, off settings) and then I removed the chain since the speed control would now control on/off/and speed functions. To be as "correct" as possible ... Since the new cable going to the speed control now technically carries "Hot" to the control and then back to the fan motor, use a black magic marker to color the ends of the white wire black. That gives fair warning to others that both lines in the cable are hot. I mounted the speed control in a hallway from the garage into the house, just below the fan. I noticed that the speed control housing itself is a heat sink that sits out about a half inch from the wall, so I mounted the switch above shoulder high so that we would be less likely to bump into it. After setting the "lowest speed" adjustment so that the shutters would not flop closed, all works perfectly. My fan is a direct drive motor that pulls 5 amps and this particular speed control is rated for 8 amps. The control gets slightly warm to the touch when it has been running on low for a long time, but the heat sink dissipates the heat very well. If your fan has shutters, make certain to keep the low speed high enough so that the shutters don't start to close. If they do, it is progressive. The shutters close a bit; the fan pulls harder and slows a bit, and then the shutters close more. Eventually the shutters are almost completely closed and flopping. In that case the fan motor is working hard and getting no air movement so it could overheat .... NOT a good thing!

Bought this to use on my attic fan. Easy to install and works great