Heating Element Control

byacey · Post by **byacey** » Sun Oct 21, 2007 10:10 pm

One thing I didn't see mentioned and should be noted is the triac heat sink. Some triacs have an insulated heatsink tab, and others don't. If you use the non-insulated type and bolt it directly to a grounded heatsink, it suffers instant death upon either power up, or commutation.

defcon4 · Post by **defcon4** » Tue Oct 23, 2007 11:04 am

Ok, I think I finally figured out the wiring diagram thanks to whoever posted pictures of the one they built. This has probably already been answered but it probably went over my head.

I have a standard U.S. residential electricity service so I'm guessing 120V.
My heating element is a 1000 watt hotplate (will this controller work with that?)

1: What wattage/specs should the dimmer switch be?

2: Will the dimmer allow me to select a wide range of power outputs to my element (ie: if the dimmer is at 50% and I move the dimmer a quarter turn up (25% more up), will the output be at 75%?) Or will it be a crude adjustment.
I guess a better way to ask this is, will the dimmer switch accurately control the power or will it be sporadic?

3: How big or what kind of heatsink do I need to attach the resistor and triac to?

I'm sorry I've never done this before. Thank you!

Post by **shadylane** » Sun Oct 28, 2007 12:45 am

I've been using 6 500watt @ 240v strip heaters clamped to a 5 gallon ss soda keg, with a omron temperature controller and a relay rated to handle the current. I have another keg I use as a thumper/slobber box. I could just use switch's to turn on only the heaters I need, but I like to be able to control them better since I have about twice the power I really need. Yes I have slobbered my thumper full of foam may a time.

Post by **shadylane** » Sun Nov 04, 2007 3:14 am

Out of curiosity where is everyone putting their thermocouples? I run a pot still with a thumper. I have one in the boiler (mash) for watching it heat up and shut off at around 208f in case I forget and another in the thumper (vapor) for controlling the run.

punkin · Post by **punkin** » Sun Nov 04, 2007 10:21 am

shadylane wrote:Out of curiosity where is everyone putting their thermocouples? I run a pot still with a thumper. I have one in the boiler (mash) for watching it heat up and shut off at around 208f in case I forget and another in the thumper (vapor) for controlling the run.

I have a pot still too, but i don't measure temperature at all except with my hand to follow the steam when it's coming up to temperature along the still head.

pintoshine · Post by **pintoshine** » Sun Nov 04, 2007 4:35 pm

I am developing a kit for the 220-240 voltage systems.
The kit will include:
A circuit board.
Short leads to connect to power.
Short leads with lugs to connect a heating element.
40 amp triac with wires attached.
6 amp triac with wires attached.
power resistor with leads attached.
capacitor
Diac
variable resistor with wires attached.
Heat Sink
I will be posting pictures soon as I get the rest of the parts in. I will be posting a how to assemble guide as soon as I get the parts.
The circuit board design is done and I have prototyped one.
I will keep you up to date as progress happens.

CoopsOz · Post by **CoopsOz** » Sun Nov 04, 2007 4:58 pm

Excellent Pint, I'll put in an order!

mtnwalker2 · Post by **mtnwalker2** » Sun Nov 04, 2007 6:50 pm

Seems to me like the perfect pot would be an insulated hot water heater,
with the top element for the quick boil and a controlled element below.

I do everthing outside in the summer with propane, but the winter and winds are different.
Pint O Shine, if you are going to market that controller, sign me up also. This is for neutral spirits which I like to make for infusions and vodka.

Next project is to develope either a double boiler for distillation on the grain, or useing a steam generater which seems more practical.

Ah well, one step at a time.

Rudi · Post by **Rudi** » Mon Nov 05, 2007 2:18 am

Yep Ill be after one too Pint

alice · Post by **alice** » Wed Nov 07, 2007 10:58 pm

I'd be very interested in one too.

defcon4 · Post by **defcon4** » Fri Nov 09, 2007 6:32 am

Here's my build of the heating element control that pintoshine posted. 120V version.

It's a sloppy build but it's also my first electrical project besides wiring light switches and outlets. Let me know what ya'll think of it

fergie · Post by **fergie** » Sat Nov 10, 2007 12:06 pm

Has anybody tested the router speed control to see if it works?

there are a lot of people saying it won't but has anyone tried yet?

defcon4 · Post by **defcon4** » Sat Nov 10, 2007 12:21 pm

fergie wrote:Has anybody tested the router speed control to see if it works?

there are a lot of people saying it won't but has anyone tried yet?

This thread explains why it won't work for a heating element. Save yourself some time and build pintoshine's controller from the schematic he posted. I just built mine and used it this weekend and it works like a charm (and only cost me about $25-$30)

guest · Post by **guest** » Fri Nov 16, 2007 10:47 pm

Hey, All

So I'm about to add 2 1500w elements to my 15 gal keg I was wondering where is the best place for them?
I normally use propane.
I plan on using both till it gets around 50 deg or so then just use one with the dimmer to control the temp.

Thanks

Post by **shadylane** » Sat Nov 17, 2007 5:06 am

If they are going to be internal, be sure to keep them below the liquid level or they will burn out. Also you want to keep them off the bottom of the still or the solids may scorch. I've run 1500 watt hot water heaters in the bottom of 5 gallon kegs but I burned out the heater after a while.

CoopsOz · Post by **CoopsOz** » Thu Nov 22, 2007 5:34 pm

Pint, the kit just arrived.....it looks like you have put in a lot of work, thank-you. I won't get the chance to build it for a couple of days but I'll keep you posted. BTW, the one I tried to build a couple of months ago was never going to work, the triac and cables I used were of a much smaller gauge.

CoopsOz · Post by **CoopsOz** » Sun Dec 02, 2007 8:32 pm

Pint, I notice that the kit doesn't have an earth....would I do any damage to anything if I ran the earth from my outlet, through the box and to my boiler? I'd feel a whole lot safer with a chassis ground.

Post by **HookLine** » Sun Dec 02, 2007 8:48 pm

Do not run it without a good earth to both the boiler, and the control box (if it is metal). Running without an earth is a bad idea generally, especially when you are mixing electricity and fluids (and flammable fluids at that).

Wait for Pinto's response, but I can't see any reason you can't use an earth.

pintoshine · Post by **pintoshine** » Tue Dec 04, 2007 7:49 am

In the USA the only part of the controller that can be earth ground is the heatsink and the case on the potentiometer. Our 240 vac consists of two lines a neutral and an earth. Both sides of the hot are not earth potential ad cannot be grounded.
I would say that for all systems this would be the case. Grounding the boiler is always a good idea.

modul8 · Post by **modul8** » Tue Dec 04, 2007 1:47 pm

CoopsOz, I just passed the earth from the mains side straight though to the earth on the boiler cord side. I am using plastic for a case so I didnt earth the kit.
I used a small electric heater for the case. Looks pretty funky actually. I will post a pic later when I have finished. (Just have to put a socket on the ouput.)

I am also thinking of adding protected (recessed) test points for my DMM to measure volts as I run.

The guys at work (electronics techs) said they were impressed with the simplicity of the design and the high load rating of the components, so thanks Pint

m

mikeac · Post by **mikeac** » Thu Dec 06, 2007 1:27 pm

Stillhead wrote:
2) Run a diode and a switch. The diode must be >10A. When the switch is on, the electricity will run through providing 1500W. When the switch is off, the electricity will run through the diode, providing 750W.

Bryan.

I'm just wondering if anyone has tried this? It seams simple and cheap and I don't think I really need all the variability that comes with the dimmer.

CanadianBrew · Post by **CanadianBrew** » Sun Dec 09, 2007 1:17 am

would this not work??? Pinto can you let me know

CanadianBrew · Post by **CanadianBrew** » Sun Dec 09, 2007 1:20 am

[quote="CanadianBrew"]would this not work??? Pinto can you let me know[/http:/

CanadianBrew · Post by **CanadianBrew** » Sun Dec 09, 2007 1:24 am

ebay search: inline thermostat reedy heater

mikeac · Post by **mikeac** » Sun Dec 09, 2007 9:42 am

I don't think you want a thermostat...well i know you don't want one...the answer is in here somewhere I have read why, but I can't re-find it right now...Sorry

Post by **rad14701** » Sun Jan 20, 2008 5:02 pm

CanadianBrew wrote:would this not work??? Pinto can you let me know

I don't think bouncing the topic with re-posts is going to get your question answered any quicker, and is against the guidelines of conduct in most forums...

Now, that being said, are you referring to the use of a diode for cutting power output in half...??? If so, yes, it will work... What this does is to only allow one phase of the AC cycle to pass through the circuit, essentially cutting the current flow in half... The diode needs to be properly sized to avoid failure, however, perhaps double the intended service amperage...

Pikluk · Post by **Pikluk** » Sun Feb 03, 2008 5:14 pm

today i got
a cheap dimmer(checked inside there was a coil on a donut, 2 chiclets and 2 small resistance)120v 600w
a triac(best i could get local was 600v 25amp)
and a 75ohm 25w resistance(best i could get local was ceramic)

first you think this is the schematic i should follow?
i want to power a 1100w hot plate on 120v 60hz.
http://www.amsyrup.com/sloj/images/120vac40a.jpg" onclick="window.open(this.href);return false;" rel="nofollow

second is the resistance is the same for a 25amp triac?

as for the resistance i thought about mounting it on the heatsink with some heat transfer grease got a nice amd cpu heatsink should be enough for both triac and resistance.

edit: there was also something that looked like a triac in the dimmer.

Post by **rad14701** » Sun Feb 03, 2008 5:30 pm

The last 120V 600W dimmer I took apart only had the potentiometer, one capacitor, and a quadrac (triac with built-in diac)... Because the quadrac was proprietary I am guessing that it was 200V 8A rated as they are only made in a limited number of sizes...

Regarding the schematic, I have considered building that one but have been procrastinating... I was also planning on using a CPU heatsink as I have dozens of them kicking around...

I tried building a controller from scratch last week but couldn't locate a quadrac, nor could I locate a diac, locally... The circuit I built didn't work properly due to the lack of the diac... I've been too busy to dig through my stash of parts to see if I have an adequate diac squirreled away...

Cmonster · Post by **Cmonster** » Sun Feb 03, 2008 9:47 pm

It looks like there has been some great experimenting over a number of years on this topic - and great work pintoshine.

I've only just found this thread today, but I've spent the last couple of weeks putting together a controller based on the technology I am familiar with. I've done a test run so far on just water, and I'm patiently waiting for a sugar wash to ferment out to run it on the good stuff.

First, to explain, I have a sankey 50 litre boiler with a 3600W element in it (240VAC in Australia). I've also been building a great variety of control gear for many years for automated homebrew beer machines, including PC based and microcontroller based. I have a professional history of being involved in process control and in particular automating broadcast transmitting facilities.

I've only just joined this forum, so in a sense I've seen the need to control an electric heater with new eyes - and this is what I've come up with:

Using a picaxe 08M micro (see revolution education - free software in basic language and easy-easy to use) with a temperature probe and potentiometer controller hooked up to a DC controlled triac, I can control my electric boiler as follows:

If the temperature is low (say below 70 deg C - but can be set in code), the power is at maximum (3600W).
When the temperature is between a set range (say between 70C and 90C - again set in code), the power level is set by a pot. In my case the pot is marked in 50W steps from 500W to 1000W with OFF at the low end and ON MAX at the top end.
When the temperature is higher than the upper limit, the electric heater automatically powers off.

The power level is set by a cycle of 20ms on and off on the element (this could be customised again in code) and by using a zero-crossing triac, the switching is done at zero volts.

Even if it sounds complex, I believe it is no harder to build than circuits suggested, and because it has a micro at its heart it is far more versatile. I suspect it might even be cheaper - but I haven't had a good look at pintoshine's kit.

I'd be happy to share code, circuit and build photos - if someone can tell me how to put photos up on the forum.

cheers all, and happy power sharing

Pikluk · Post by **Pikluk** » Mon Feb 04, 2008 7:39 am

one more question do i have to remove th existing control on the hotplate or just putting it at max should be ok?

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