Rotary Dimmer Stir Plate

[danthebugman]

I've started putting together a stir plate and was curious if one of these rotary dimmers would work to both turn the stir plate on/off and regulate the stir bar speed? I've been skimming through various forum posts and can't seem to get a definitive answer (some seem to indicate yes, some no, some say it isn't safe). This is the last thing I need to figure out before I can drill holes/wire things up so any advice is appreciated.

 

[danthebugman]

Also, can anyone explain the wiring in this post a little better. I think I've got it, but the picture they show is confusing me a little bit.

 

[m1batt1]

I don't see why a rotary dimmer wouldn't work. In theory with the dimmer turned all the way down it's off. Not to mention the fact that if you're building the setup you've linked in the second post you'll be using low DC voltage. That would minimize any hazards as far as I can see.

As far as the wiring setup I'm on my phone and can't get the photo to zoom so I can't be much help there.

Sent from my SGH-I747 using Home Brew mobile app

 

[day_trippr]

The linked dimmer model is an active electronic device meant for controlling AC. It's unlikely to work as a rheostat for DC as in the linked article. It's possible it could be used to control the AC input to a wall wart which may allow controlling the DC output voltage level, but there's no guarantee that will work...

Cheers!

 

[Wynne-R]

Post #1 If you do this, use a transformer, 120-12 volts. Also be sure to fuse it at 1 amp.

Post #2 That’s just nuts. Using a rheostat (potentiometer) is crude, and they never specified values.

I’d use this: http://www.stirstarters.com/instructions.html
hint- the capacitor is optional unless you’re having radio interference.

 

[alphaomega]

Or you could just buy a LED dimmer for a couple of bucks from eBay and get true pwm control (that means better efficiency and lower RPMs).
Way better than rheostats or linear voltage regulators and probably cheaper. Oh, yeah... No soldering required either.

 

[Hang Glider]

One fellow on these forums actually acquired an AC fan - in which case a common dimmer would work fine.

 

[danthebugman]

Thanks for the replies everyone. Seems like I'll have to go a different route then. Those LED dimmers look like what I'm after and I even found this dimmer with remote control. Pimp factor...oh yeah!

 

[Hang Glider]

I got this one e-bay PWM but it made the motor scream like a monkey (not fast, actual piercing noise) so I tried this one another e-bay pwm and it works like a champ. However - it did take 2 weeks each time for it to ship in from Hong Kong...

use this term "pwm dc motor controller" in e-bay, there are tons to pick from (PWM = pulse wave modulation, just in case you didn't know.)

 

[alphaomega]

Or search for "led dimmer 12v 8a". They are cheaper and work really well for this.

 

[raouliii]

....(PWM = pulse wave modulation, just in case you didn't know.)

Actually it's, Pulse Width Modulation

 

[Hang Glider]

ahhh, thanks!

 

[day_trippr]

[...] I tried this one another e-bay pwm and it works like a champ. However - it did take 2 weeks each time for it to ship in from Hong Kong...[...]

I can vouch for that second switcher, I built two stir plates using that model and they work great. The only thing I wish it had was an on/off control integrated into the pot, but it wasn't a big deal to add a micro spst switch...

Cheers!

 

[Black Island Brewer]

I got this one e-bay PWM but it made the motor scream like a monkey (not fast, actual piercing noise) so I tried this one another e-bay pwm and it works like a champ. However - it did take 2 weeks each time for it to ship in from Hong Kong...

use this term "pwm dc motor controller" in e-bay, there are tons to pick from (PWM = pulse wave modulation, just in case you didn't know.)

I tried that first one too, and hated how loud it made the fan. It made me start using my stir plate in my fermentation chamber instead of the kitchen counter. So the second one worked without the noise?

 

[Black Island Brewer]

Or search for "led dimmer 12v 8a". They are cheaper and work really well for this.

Would that be a dimmer like this? Can you share how it worked for you?

 

[Black Island Brewer]

I can vouch for that second switcher, I built two stir plates using that model and they work great. The only thing I wish it had was an on/off control integrated into the pot, but it wasn't a big deal to add a micro spst switch...

Cheers!

When I used that first one, I'd turn it off by unplugging it!

Sadly (or happily, since it made so much damn noise) I has a starter overflow, and the liquid dripped into the cigar box and burned out the PWM unit.

 

[day_trippr]

When I used that first one, I'd turn it off by unplugging it!

Sadly (or happily, since it made so much damn noise) I has a starter overflow, and the liquid dripped into the cigar box and burned out the PWM unit.

Sounds like it had it coming..."eJustice"...

Cheers!

 

[alphaomega]

Would that be a dimmer like this? Can you share how it worked for you?

Yeah, that would be the one. I use one for speed control of my stir plate (DIY with computer fan) and one for flow control of a DC (solar) pump during mashing (actually I use a third one, that is modified, to generate PWM for an SSR to drive my dirt cheap RIMS heater). They provide about 1kHz (when not modified), and work really well, at least for me. Even though in audible range, I hear no screeching or screaming from the motors. Even though it says 12v, I actually feed with a 9v wall wart. The logic is driven from a 7805 regulator, so probably anything from about 6v to 24v would work (well, don't quote me on this, and if it works make sure not to overload).
PWM is generated by a simple 555 circuit, but through a bit of clever design it really goes from true 0 to 100% duty.
I absolutely love these, so cheap and very useful.

When I used that first one, I'd turn it off by unplugging it!

Sadly (or happily, since it made so much damn noise) I has a starter overflow, and the liquid dripped into the cigar box and burned out the PWM unit.

And that would be the exact reason why an AC fan and dimmer would be such a bad idea.