Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

question about dimmer

Status
Not open for further replies.
does ceiling fan dimmers (triac based speed controllers) reduce fan motor's lifetime?

The dimmers in fans are actually potentiometers. Every motor has a maximum currrent it can handle. If you limit the current, providing less and less current, the fan will go slower but the lifetime will go up. If you go over the current level, the lifetime shortens. It's just like an LED. On LED specs, you'll find something like 20,000 hours or 30,000 hours based on a specified current which is usually 20-30mA.
 
The dimmers in fans are actually potentiometers. Every motor has a maximum currrent it can handle. If you limit the current, providing less and less current, the fan will go slower but the lifetime will go up. If you go over the current level, the lifetime shortens. It's just like an LED. On LED specs, you'll find something like 20,000 hours or 30,000 hours based on a specified current which is usually 20-30mA.

well what i meant is triac or SCR based phase control dimmers
 
Last edited:
maybe they changed AC motors recently, but a rheostate (pot) "dimmer" to an AC induction motor won't work. Take the control guts down out of a three speed fan and you will find a selector switch and two capacitors:

speed 1 = cap 1

speed 2 = cap 2

speed 3 = cap 1+2

There is no pot. I did buy a fan a long time ago with a "solid state" speed controller with a pot and the motor failed along with the controller. If you starve the current going to an AC fan, the motor will eventually stall at a very abrupt point. That's how I have seen fan motors work. Running the motor slower (near stall) actually makes it get hotter.
 
Last edited:
TRIAC based dimmers do not regulate current. They change the "duty cycle".

Yes aruna1, poorly designed, minimal parts dimmers DO reduce the life significantly - mainly via overheating of the fan coils as well as no "soft start".
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top