Adding Speed Control to Roof Fan

[JoRow]

I have a cheap 14" RV fan (freebie) that I installed in my roof vent. 

It works really well but it's pretty loud and it only has one setting. I'm wondering if I can add some sort of speed control dial to it to save power and make it quieter. From what I've found out, I can only add a PWM controller if it's brushless.

How can I tell if my fan has a brushless motor?

Does adding a PWM controller or something similar save power?

 

[bseek]

Not sure if this will help you, but this is what I did to my Fantastic fan and it works great.

http://www.wanderthewest.com/forum/topic/10848-fantastic-fan-variable-speed-control/

 

[SternWake]

I have heard some brushed motors do not like pwm pulses long term. But not that all brushed motors everywhere cant handle it.
A brushless motor has no resistance when one pulls and pushes , not turns, the impeller through its range. A brushed motor will have some resistance as the brushes rub on commutator.

If you go pwm. Find one 21 khz or higher or you might hear it whine at slower speeds.

Slowing fan does reduce amp draw. Either with pwm signal or resistors

 

[JoRow]

Perfect thanks guys


Sent from my iPhone using Tapatalk

 

[ZoNiE]

For LED's, may take the amp draw of the fan, may not.for three bucks, this one is worth trying.

Amazon

 

[SternWake]

I have several of the above led dimmer.

They do slow.my computer fans, but they whine annoyingly. Loud.at reduced speed because they pulse at only 13 khz.

Google.search:

Pwm motor speed controller 21 khz

There are a few that go this high.