Heating Element Control

[Bob421]

I am very scattered this time of year so it takes me more time than I like to get projects done. And way too much time to overthink them while I am at work. I think I will try just using the chip. If I have to I will suspend the elment in a bucket of water to test it. I don't want to cut a hole in my keg until I am sure it works.
I will let you know how it goes. Probably this weekend.

[Bob421]

Bob421, the filter circuit is not required... The UA PSR-25 only needs the correct potentiometer for the mains voltage used as well as a heat sink... I am seriously considering building one of these units... I'm relatively certain that one of our members is using one of these although the maximum wattage may be different...

That would be great. The reliabilty factor would seem to be better also. I would hate for my cheap dimmer chip to go out partway through a run and have to scramble to rebuild the control.
I may just order one and try to figure out what I need for a pot for 220v. I can manage a heatsink pretty easily with all the old CPU heatsinks I have around.

[Bob421]

Told ya I was scattered. A quick glance at the data sheet shows 250k 1 watt pot.
Should be a really simple setup. Still gonna try the triac thing but I like the psr25 a lot. I can get on for 45 bucks plus shipping.

[Bob421]

Ok i got my control mostly built. Here is the schematic I used. Originally posted by pintoshine. I noticed tonight that he posted an updated version that is a little different.
Hope this I hope this version will work.

Here is a somewhat blurry view of my contraption. I want to wire in a switch inline with the resistor to keep it from coming on when i don't want it to. I have the switch just laying there about where is would go in the circuit. Next i have to drill and mount the two chips and the resistor to the box with some heatsink compound.
Anyone see any problems with this setup let me know before I pug it in

BTW I went ahead and welded my half couplings into my keg so there is no turning back now.

[olddog]

Make sure that switch is rated for the current and ampage you will be using, it looks a bit lightweight to me.

OD

[Bob421]

It is rated at 277v 10amps. Cuts power to the dimmer chip so it should be plenty big enough. If I remember it only takes 4 amps to turn on the triac. If I am wrong about this let me know.

[rad14701]

It is rated at 277v 10amps. Cuts power to the dimmer chip so it should be plenty big enough. If I remember it only takes 4 amps to turn on the triac. If I am wrong about this let me know.

That 4A figure sounds about right... Only very high current triacs can handle more than 4A at the Gate with most being in the 2A or lower range...

[Bob421]

OK I just ordered a psr25 and a pot. Couldn't take it I had to have some sort of a backup that doesn't rely so heavily on a cheap dimmer.
So do I just break one leg of the circuit with the load side of the psr25? Seems like there must be more to it.

[Pamulli]

OK I just ordered a psr25 and a pot. Couldn't take it I had to have some sort of a backup that doesn't rely so heavily on a cheap dimmer.
So do I just break one leg of the circuit with the load side of the psr25? Seems like there must be more to it.

Bob,
Did you try your circuit as is without the new chip? I'd be very interested in knowing if it works since I'm in the same boat and still haven't tested mine.

Thanks,

[Bob421]

I don't have a couple of little thing I need. Hope to fire it up this weekend.
Will let you know

[Bob421]

Got the triac, resistor and dimmer chip all mounted to the side of the aluminum 2gang box with heat-sink compound (I sanded off the paint first). I fully expected the lights to go out the moment I plugged it in. I filled the keg to a few inches above the element with some water and vinegar, plugged it in and turned it on. But nothing happened, no lights going out or dimming, no hum no nothing. My first thought was to get out the multimeter and try to figure out where I went wrong. Then I shined the flashlight down into the keg and saw heat waves coming off the element through the water. YeeHaww!!
I got it up to a good boil and I can regulate it quite well with the pot and I can hear what is going on in the keg very well without the noise of the gas burner.

I do have to say it needs a better heat-sink. The resistor and dimmer chip are fine on the side but the side with the triac chip got very hot and I will definitely have to add a heat-sink to it on that side.
Here is a picture of it kink of exploded on the floor. I didn't want to close it up until I tested it. The keg is on bricks because I added a drain to the bottom. I need to add some sort of a stand but I dont have any stainless right now.

I got the psr25 so I will be making another control in the next couple of weeks with it.
I have to order another pot because the one that I ordered from Newark is not a type you can put a knob on.

Still didn't get any validation on the wiring of it.
Rad, do you just break one leg with the load/neutral side of the psr25 and connect the pot to the control side and that is it?

Thanks for all the help guys.

[LWTCS]

Love the twist and locks.
Hope you can protect your connection to the element a bit better.

[MuleKicker]

Hey Larry, did you just weld a junction box with the back cut off to your keg? i like that. I have to say, my keg connection is the weak point in my setup right now.

[LWTCS]

Yep just a couple of tacks on either side.

I also cut the back side to conform a bit better to the roundness of the keg. Fits very nicely.

That is not a regular box by the way. It is a box extendor. It has the open back.

[LWTCS]

I wuz thankin bout a whole new harness for my new controller.

But after seeing how you set it up, I'm gonna add a female twist and lock for input, and a corrasponding male for output and I can just add the device to my harness quite easily.

Everything is going to marry up beautifully. Wire size and all.

[Bob421]

I wuz thankin bout a whole new harness for my new controller.

But after seeing how you set it up, I'm gonna add a female twist and lock for input, and a corrasponding male for output and I can just add the device to my harness quite easily.

Everything is going to marry up beautifully. Wire size and all.

When I build a stand for it I will provide some more protection and strain relief for the lead to the element but it is pretty well protected by the shrink tube for the time being. I like the twist locks but would like there no to be any lead coming off the keg at all when it is disconnected. I saw one time a receptactle box that had a recessed male connection but haven't seen anything like it lately. Remember that the element side has to have the male so you don't end up with the exposed plug live.

[Dnderhead]

""element side has to have the male so you don't end up with the exposed plug live.""
something Iv thought about you mite be able to use,,on diesels they have "plugs" that are much like a trailer plug ,,used for plugging in a lead cord for a heater.
these are enclosed

[rad14701]

Still didn't get any validation on the wiring of it.
Rad, do you just break one leg with the load/neutral side of the psr25 and connect the pot to the control side and that is it?

As mentioned previously, I haven't built a 240V controller to date... Yes, you run the controller off one hot 240V lead and run the other hot lead directly to the other side of the heating element... Because the two are 180 degrees out of phase the controller manages the amount of phase angle for both sides of the circuit...

[cob]

""element side has to have the male so you don't end up with the exposed plug live.""
something Iv thought about you mite be able to use,,on diesels they have "plugs" that are much like a trailer plug ,,used for plugging in a lead cord for a heater.
these are enclosed

recessed plugs are available at recreational vehicle supply outlets, but heat tolerance could be an issue. cob

[LWTCS]

Right you are dunder. I did not mean to get that backwards.

[Pamulli]

Bob,
Congrats on a working controller.
Did you use the dimmer switch as is or did you take it apart and only use the chip? I am planning on using my dimmer as is and wondered if you did the same?

Thanks,

[Bob421]

No, I was going to use the dimmer circuit with a new pot and capacitor. But I ended up just unsoldering the chip and using it in the circuit. It worked well on a run I did last night. Except the control seemed very sensitive. Like there is about a sharpie marker mark between a good boil and no boil. I ended up at about 75 percent of the travel of the potentiometer for most of the run. I didn't get to collect tails because I ran out of time. All the way up brought my ten gallon batch to boil in about 50 minutes with my 5500 watt element. It also made the triac very hot. Even with an extra little heatsink I made out of a piece of square aluminum tubing. At running settig it was just a little warm.
I monitor the reflux condensor water out temp to give me and idea of what is going on. I like to run it between 110 and 120 and when I tried to ease the heat up a little a time or two I got a big spike in condensor temp. I don't think my condensor would keep up with this thing at full output. Unlike the propane where I had no problem with it wide open.
I have to put a few runs on it to really learn it now.
It worked really well and the loudest thing in the shop now is the water going through the needle valve.

[Bob421]

Still didn't get any validation on the wiring of it.
Rad, do you just break one leg with the load/neutral side of the psr25 and connect the pot to the control side and that is it?

As mentioned previously, I haven't built a 240V controller to date... Yes, you run the controller off one hot 240V lead and run the other hot lead directly to the other side of the heating element... Because the two are 180 degrees out of phase the controller manages the amount of phase angle for both sides of the circuit...

I missed this reply but thanks.
I have to order another pot and figure out how to mount a CPU heatsink on it and give it a try.
Maybe I can have a bigger Usable range with it that the triac setup.

[rad14701]

Bob421, you could experiment with a 1/2 watt parallel resistor across the terminals of your potentiometer... 220K, 330K, 470K, 560K, and 680K Ohm resistors would be good choices to see if one of them helps reduce adjustment sensitivity and gets you where you want to be... Start near the middle and work from there to fine tune... Another option would be to use a variable resistor (trim pot) that covers a similar range...

[MuleKicker]

Here is my finished heat controller. My partner in crime is an industrial electrician, so between the 2 of us we put this together. The top number is the collumn temp in .1C, right before the condenser. The temp right below that is the set temp. if the collumn temp reaches the set temp, the heat turns off. The 3rd temp down is the boiler temp. The bottom number is the percentage of power to the element. The pic was taken towards the end of this weekend's stripping runs. We have been tweeking the programming on this thing for a while, and I have to say with the additition of a phase angle control relay and a few programming changes, its right on the nuts.

[LWTCS]

Jesus H. Brian. That is a handsome looking peice of equipment.

[MuleKicker]

Yeah, alot of trial and error to get to this point. 3 years to get to this point. I have a feeling, if I had a few more of these things around you would own one

[LWTCS]

It would seem the mule has a flare for the obvious ( I says to meself).

[kiwistiller]

Wow, that's some amazing work mate.

What's the brains in that contraption?

[Bob421]

Bob421, you could experiment with a 1/2 watt parallel resistor across the terminals of your potentiometer... 220K, 330K, 470K, 560K, and 680K Ohm resistors would be good choices to see if one of them helps reduce adjustment sensitivity and gets you where you want to be... Start near the middle and work from there to fine tune... Another option would be to use a variable resistor (trim pot) that covers a similar range...

Cool thanks I will try that.
Also would like to find an amp panel meter reasonably priced so that I can have some indication of power applied.
A quick search a mouser turned up the expensive ones(several hundred dollars sometimes) but I haven't sat down and really gone after it.