PWM..Show us How

[bigljd]

That's great! I love my electric system. I too noticed that these PWM devices are never 100%. So I put in a switch that allows me to by pass the circuit and supply either 5v or 0v consistently to the SSR. It is a 3 way switch that will send all voltage to the SSR, send the voltage to the PWM or not send anything at all. I turn it full on until I have a rolling boil, then I switch it to run through the PWM.

That's a good workaround to the problem. I'm OK with it being less than 100% power though, since I normally start heating the wort while I'm sparging when wort completely covers the element. Even running at 60-70% power during the sparge I'll usually be close to a boil by the time my sparge is complete. I may have to run it at 95% for a couple minutes to get it to a rolling boil, then I can dial it back down again. Can't wait to try this thing out!

 

[FrFtr28]

I have my board all put together, but when I test it the light on the ssr stays on longer when the dial is turned down. It's as if something is reversed and when the dial is turned all the way up, the element is heating less if that makes sense. Any idea what the problem could be?

 

[stamandster]

I have my board all put together, but when I test it the light on the ssr stays on longer when the dial is turned down. It's as if something is reversed and when the dial is turned all the way up, the element is heating less if that makes sense. Any idea what the problem could be?

You have the left and right connections on the potentiometer switched.

 

[FrFtr28]

You have the left and right connections on the potentiometer switched.

That was the problem. Thanks for the quick response!

 

[stamandster]

That was the problem. Thanks for the quick response!

That's only because I did the same exact thing

 

[tdiowa]

Fired mine up for the first time this weekend!!!

It works!!!

Thanks to everyone who shared their information on this project. Doing things like this is almost as much fun as drinking the beer I make.

On to the next project...

TD

 

[KingsTab]

I love the quick response of a PWM when you have boil overs. Such a great idea!

 

[chuckjaxfl]

Mine:

https://www.homebrewtalk.com/f51/chuckjaxfls-pwm-344952/#post4296437

 

[kzimmer0817]

Here is a pic of three of them fully assembled and hot-glued..

Clearwaterbrewer,

I thought that this was Walker's PWM, so I PMed him about it; now I realize that it's yours. I'm trying to decide between his, yours, or the little kit that has been recommended (with the substitute capacitor)

I hate to be asking to be spoon-fed, but I sure would like to see a diagram of your PWM. I've looked at the circuit-bee schematic. I'm a little bit familiar with circuits from my college physics classes in 1979. But . . . the way the individual components look when connected together isn't always obvious from a schematic.

I would greatly appreciate it if you would supply a drawing of how the actual components attach to the potentiometer - even if hand-drawn and not even artist quality. Did I read that you don't solder these to the pot but use hot glue to hold everything in place?

Thanks,
Keith

 

[maltbarleyhops]

Here's a diagram I made. I tried to keep it simple. Hopefully it's enough to get you going. It's easier to understand once you get your hands on this stuff and start piecing it together.

this would be an "dc to ac" ssr correct?

 

[stlbeer]

this would be an "dc to ac" ssr correct?

Nope. The dc side of the SSR controls the flow on the other side.

Only 1 leg of 240v or the hot side of 120v flows through the SSR on the switched side. This is where the AC is.

The control circuit is DC and controls the off/on of the Solid State Relay.

AC is being converted to DC by the wall transformer to power the PWM.

 

[maltbarleyhops]

i worded that wrong. what i meant was the ssr must be dc on the pwm side and ac on the hot side. correct?

 

[GregKelley]

Yes, as the previous poster noted. DC is fed to the control side of the SSR. The AC voltage passes through the switched side.

 

[maltbarleyhops]

Yes, as the previous poster noted. DC is fed to the control side of the SSR. The AC voltage passes through the switched side.

Uh,yeah.....i kinda got that.


But thanks so much for pointing that out anyway!?

 

[stlbeer]

i worded that wrong. what i meant was the ssr must be dc on the pwm side and ac on the hot side. correct?

Correct...

 

[user 125772]

the easiest setup is documented about half way down this page:
http://homedistiller.org/forum/viewtopic.php?f=2&t=3342&start=915

 

[rilewedge]

IF your using 120V you may want to look at this thing:

http://www.ebay.com/itm/MLCS-9410-2...425598699?pt=Routers_Bits&hash=item19b5e0eaeb

 

[szazman73]

So i bought all the components from mouser to build walker's pwm. I have it all assembled and hooked up to my ssr. The ssr I have has an led indicator light. My question is should this light be blinking at a rate that matches how far up I turn the pot. Right now once I turn the pot on the light goes on steady.

 

[-TH-]

So i bought all the components from mouser to build walker's pwm. I have it all assembled and hooked up to my ssr. The ssr I have has an led indicator light. My question is should this light be blinking at a rate that matches how far up I turn the pot. Right now once I turn the pot on the light goes on steady.

One thing that happened to me is the wall wort I was using for power turned out to be lower voltage than the 12V it was rated for. It would only power my test light solid. Once I hooked up another wall wort that truly did put out 12V, it worked as it was supposed to.

 

[nilo]

Here's a link to thread with another PMW board option.
https://www.homebrewtalk.com/f170/simple-ssr-pwm-power-control-356991/

 

[stamandster]

Just in case someone didn't want to build one I think that this would be useful

http://dx.com/p/1-ch-96w-manual-led-strip-dimmer-white-dc-12v-163667?item=25

You have to add a SSR anyways sooo... seems like it'd work. 12v input though.

 

[pvtschultz]

That LED dimmer will operate at too high of a frequency to use with an SSR.

 

[stamandster]

That LED dimmer will operate at too high of a frequency to use with an SSR.

Really?? Even on low? hmm... wonder if you could take it apart like the bakatronics and adjust it.

btw that was a freakin' fast reply dude

 

[pvtschultz]

The frequency does not change, just the pulse-width or duty cycle. I have taken them apart and the circuitry is very small in there. I don't think that you'll be able to do the component swamp like the Bakatronics unit.

 

[Dirty]

I just hooked up my pwm and wish I had done so sooner. Just need a heat sink for the ssr. It gets pretty warm.

 

[fhhobbies]

These guys over here are building basically the same thing i think with just a pot and ssr , doesnt seem to be much more then that or am i missing something? i need a simple knob control for my BK and this looks cheap and easy.
http://homedistiller.org/forum/viewtopic.php?f=2&t=28364

 

[fhhobbies]

http://homedistiller.org/forum/viewtopic.php?f=8&t=26221

 

[alha]

If we're controlling 5500W elements, and I believe it's better to oversize things a little rather than sizing them at capacity, would this be a good fit for these elements? http://www.ebay.com/itm/6500W-thyristor-Voltage-Regulators-dimming-speed-thermostat-control-/160833921374?pt=LH_DefaultDomain_0&hash=item257272e15e

Not inexpensive, but would it eliminate the need for the SSR, and the thought of fewer parts, so the potential of less going wrong? Appears to be built appropriately beefy enough.

 

[nilo]

If we're controlling 5500W elements, and I believe it's better to oversize things a little rather than sizing them at capacity, would this be a good fit for these elements? http://www.ebay.com/itm/6500W-thyristor-Voltage-Regulators-dimming-speed-thermostat-control-/160833921374?pt=LH_DefaultDomain_0&hash=item257272e15e

Not inexpensive, but would it eliminate the need for the SSR, and the thought of fewer parts, so the potential of less going wrong? Appears to be built appropriately beefy enough.

The circuit you listed seems to be as simple as it can get for a triac operation. It probably uses a diac, capacitor and resistor to provide the trigger to the triac. By the picture, the triac is the BTA60-800B which is a 40A triac. The frequency of switching will be 60Hz. My PWM works at very low duty cycle, something like 2Hz.
Also, triacs works better when switching at zero crossing of the sine wave (specially for inductive loads, not your case thought), which this one will not do. This may increase heat and reduce component life.

 

[Alefebvre]

So this is my second time reading this thread I have all my parts ordered to make Walker's PWM just needed some quick info on one thing regarding the 30a switch. Am I looking for a 4 pin switch? Will this one work: http://www.ebay.ca/itm/1-x-Green-Button-4-Pin-DPST-ON-OFF-Illuminated-Car-Rocker-Switch-AC-250V-15-30A-/370725294852?pt=LH_DefaultDomain_0&hash=item5650f31304&_uhb=1

Also will the light on the switch come on only when the element is on?