It comes in the wall control category and allows you to control the speed of the fan by switching between high and low beams. The modern dimmer switches might be saving more energy, but there is a high probability of such a switch to be on the fritz. The capacitors also play a vital role in its functionality as after receiving all the power from the source, it supplies the motor with a pertinent amount of energy which resultantly allows the user to set the fan speed at any desired level between off to the maximum.
Additionally, it also has the necessary variable speed control setting. It is also possible to have a setting where the switch of the light and the fan is different. If it starts immediately, all is well. If it hesitates before starting, or struggles to start picking up speed, switch off, the capacitance value is too low for safe continuous use.
Running it like this for 10 seconds is harmless, but continuous operation would be a fire risk. Fan Voltage When the fan is starting ok, then we turn attention to the voltage across the fan. Meter readings can be ignored while the fan is starting, what we need to know is the readings when the fan is upto speed. Stalling voltage is in the region of v for a v fan, so the fan must run at well above v once it has picked up speed.
If the fan voltage fails to reach this value, the capacitor is too small for safe continuous use. Take Your Pick These tests will eliminate capacitors that are too large and too small, and you can pick capacitors from the ones within the safe range. Each speed control capacitor needs a bleed resistor connecting across it. Bleed resistors need to be rated at v or greater, which means using either one 0. This greatly reduces switch arcing, which would otherwise burn out the switch contacts prematurely.
See Snubber for more information. Wiring should be sufficiently sturdy, and if any risk of wires touching anything metallic exists, the wire concerned should be sleeved. Where a slim pattress is used, and the capacitors placed in a separate box to the switch, that box should be fire resistant like any other mains wiring accessory. Unlike an ordinary dimmer, this has a three-position switch for low, medium, and high speeds, instead of a continuously variable knob.
The manual shows typical wiring, which is like an ordinary dimmer:. I've heard people say "don't run a fan on a dimmer; you will start a fire", but don't say why. Yet, that Lutron sells this device expressly for fans suggests it is something other than an ordinary triac light dimmer, and that it's totally safe, but they also don't say why. I also know when I bought this house, a different, uglier fan controller of a similar type was installed. Could it be that this ceiling fan is designed for this type of control, where others are not?
Can someone tell me, as an electrical engineer, exactly what these fan speed controllers do, electrically? How are they different from ordinary triac light dimmers? I was recently today helping someone with their home renovations, including replacement of the three-speed fan controllers. The old one, which we ripped out and replaced, is shown below. Note the crude circuit diagram on the black box object the fan speed controller.
I infer that the fan controller works by inserting a capacitance into the fan's power supply circuit. The slow speed is obtained by using the 4. I don't understand single-phase induction motors well enough to state with certainly exactly how the extra capacitance modifies the speed of the motor.
Note that single-phase induction motors aren't self-starting and must include a phase shifted auxiliary winding to provide starting torque. The phase shift is provided by a capacitor, which may be relevant. If anyone knows more about the workings of single-phase induction motors, please come forward!
My understanding of light dimmers is that they do not control voltage but cut off the voltage during part of the cycle. Thus you are reducing the amount of time per cycle the power is on. This works fine for a light which will glow through the cycle and smooth out the power curve.
I don't know why this would cause a fire. Light dimmers are usually rated at W so way more than the fan motor. When voltage is applied to each point, the main winding is energized as voltage from Black Hot wire completes circuit with White neutral wire. Likewise, how do you wire a 3 speed fan?
Identify All Fan Wires. Make sure the fan isn't plugged into a power supply. Remove the Old Switch. Take note of the position of the old switch, and mark on the new switch where the wall cord wires connect and where the motor wires connect.
Connect the Wall Plug. Solid-state controls change the level of power in the fan motor to control the speed of the fan. For instance, when you switch from medium to high on a solid-state fan , the speed control mechanism increases the power of the motor. You can change the capacitor and restore the rated speed of fan.
However, that will not make it go any faster than its rated speed. The only case it might make the fan faster is if the capacitor used were smaller than ideal to begin with. Now, when you increase the capacitance , the voltage across the capacitor decreases but that across the fan motor increases. Accordingly, the speed of the fan increases. In other words, you need to increase the capacitor value to increase the fan speed. Capacitors regulate the fan speed by regulating the waveform of power supply.
These do not get heated up and thus save electricity when the fan is running at lower speeds at higher speeds electricity consumption of fan is the same with both regulators. In a capacitive type fan regulator, various combinations of capacitors is used to control the speed of the fan.
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