Ceiling fans: AC vs DC - Page 1
Forum section: electronics / projects

author: shorts
author_rank: Newbie
timestamp: February 07, 2018, 11:29:23 am
content: Hey all,My dad recently got some ceiling fans installed which are AC. After the research he did, he said that the AC fans seem to be a lot cheaper than DC fans. We're both complete novices when it comes to electronics. I think he's a bit pissed he didn't just pay more and get the DC fans now.The thing is, he's had them installed by an electrician and has now found that with the AC fans, he really doesn't have decent control over the speed. Its either low speed or too much.1. What's the difference in terms of hardware required, space limitations etc? e.g. It seems DC fans must require some sort of AC/DC converter and how are these installed in typical Australian households?2. How does the speed control differ when it comes to AC vs DC?3. Now that he has the AC version of the fans, is it possible to convert the system to DC or is he stuck with motors designed for ACThanks.

author: Seekonk
author_rank: Super Contributor
timestamp: February 07, 2018, 04:28:23 pm
content: Single phase shaded AC motors are hard to control. They play around with the slip of the motor depending on load. You are stuck. If they could have done better with speed control, they would have.

author: schmitt trigger
author_rank: Super Contributor
timestamp: February 07, 2018, 04:38:31 pm
content: Would you mind sharing a link of the DC fan?The pure-DC ones I've seen are designed to run directly from PV installations.

author: shorts
author_rank: Newbie
timestamp: February 08, 2018, 08:33:57 am
content: Thanks. I'll ask my dad about which DC ones he was looking at. In the meantime, isn't there some sort of ac to dc converter that you can get for ceiling fans like that?

author: james_s
author_rank: Super Contributor
timestamp: February 08, 2018, 06:38:09 pm
content: AC and DC motors are entirely different, the motor is the central component and the bulk of the cost of a ceiling fan, switching would mean replacing the entire fans. I've never seen a DC ceiling fan before but I'll take your word that they exist. I have not found there to be much issue with controlling the speed of standard AC ceiling fans, there are speed controllers that will go down to a crawl.

author: schmitt trigger
author_rank: Super Contributor
timestamp: February 08, 2018, 06:52:30 pm
content: Some time ago, I was considering a home photovoltaic installation which would not cost me an arm and a leg.Back then, circa 2011, there was a manufacturing alliance which promoted pure-DC for home and small commercial applications.There were of course, LED lights, but to my surprise, there were also ceiling fans.My project did not materialize because the local electrical code could not figure out exactly what rules to apply.

author: Gregg
author_rank: Super Contributor
timestamp: February 08, 2018, 08:09:20 pm
content: Two years ago I purchased a large DC ceiling fan from Home Depot (their own brand). It only has remote control for the speed and lights which I initially thought might be a future fail point, but I really liked the design and bought it. I’m more than happy because it is so quiet that I cannot hear it with my aging ears and the speed control is superb. The lights also turn on / off / dim via the remote. It is in almost constant use.