Heating Element Control

[rad14701]

Rad, Q for you... for those with triacs and can't get the data - can you slap an ohm meter across the heatsink, and then test each lead in turn, looking for continuity? Which would indicate commonality between the heat sink and one of the leads?

I haven't worked with these devices before.

Perhaps, but that's no guarantee... In a perfect world, MT2, usually the middle pin, would NOT have continuity with the mounting tab or stud on a known good triac unless it is either non-isolated or has failed... In fact, most of the specification sheets also include troubleshooting steps to determine whether a triac is shorted out or an open circuit... Just depends on the architecture of the component...

I think I have most of the NTE, Littlefuse, and Teccor PDF's...

[redfrog]

thanks a bunch, seems to be working like a charm. I did a quick test with a pot of water and nothing blew... and i also had control of the power w no cycling cant wait to do a run!
for the record i use a 1kW cheap electric hot plate, opened it and jumped the control. The thermocouple was apparently inside the control since i didnt see any other wire in there, no fuse either, just the ground.
I used pinto first diagram
The build should've cost me about 25bucks: 15$ for the triac and resistance (ordered at electronic part store, saved 20$ on shipping), 7$ for a 15 feet extension cord (cut at about 6 inches from the female end, used for wiring and connections) and 4$ for the dimmer. i salvaged a heat sink and a box from an old computer.

looks pretty rugged, didnt seem to heat up that much but the real test is going to be the first run

thanks again guys

[Swedish Pride]

I was going to gut a cheep kettle for a 2.2kw element and throw on one of these to be able to control the boil.

http://www.aliexpress.com/item/3000W-22 ... 66913.html" onclick="window.open(this.href);return false;" rel="nofollow

I have a 33 l stockpot on order that I intend to fill with about 24 l worth of wash.

According the calc on the main site it should take about an hour to come up to the boil ( give or take depending on wash abv).
I can live with that for now, It might be different once i get up and running but for now I don't mind the theory of waiting

I would go for 4kw+ if it wasn't for the big difference in price, this will be less than 15€ where as going big would be closer to 100€ ( cost of element, controller and a sparks to do the 30amp work)

Can any of you experienced builders see any issues with my approach?

I live in ireland so its 230v 20amp on the standard plug that I was going to run it from

Cheers lads

[BigSwede]

Hello Swedish Pride from another Swede...

Lot of guys have had success with those inexpensive controls. Keep in mind, though, it is what you'd call a cheap Chinese import, and those things (of all types) can be hit or miss. They either work spectacularly well for a crazy low price, or the magic smoke makes an exit the moment you power it on. Hope you get the first.

Your 230 VAC 20A line can in theory deliver 4.6 kilowatts, MORE than enough for your boil. The controller is rated at 3 kilowatts. So if your heating element is genuinely a 230VAC 2.2KW, it should be fine, you have 800 watts of overhead. These things don't like to be run full bore, full rated, all the time, as they will get hot.

Since you are running off of a standard line there, I'd get a decent (but common) switch rated 230/20A that lets you bypass the controller. Flip the switch, controller is out of the circuit, and your mains supply the juice to the element. When it's time to control, switch her back into the circuit and dial it down as needed.

Watch/feel for heat the first few runs. You can mount it such that the Al casing is attached to a larger metallic mass to act as a heat sink. I'd also carefully test that large aluminum case to make sure it doesn't become electrically hot due to factory (or user) error; ground everything as needed.

Lots 'o babbling from the BigSwede, I think your setup will work fine. Oh yes, it's nice to have a voltmeter or ammeter in there somewhere, lets you be repeatable. A cheap analog VM will set you back 5 Euro/whatever, they aren't much.

[Swedish Pride]

Nice to see a fellow Swede on here and even better one that can help me

I do realize that it is indeed a cheep option, but that's a gamble i have to take, just the materials and tools to fabricate my first stab at a still is bringing me close to the 200€ mark.
At first I was only going to throw a 3/4 inch copper pipe i have of a existing 10l stockpot and have it running on the stovetop, but after reading here and doing some calcs i figure I probably need to go bigger to appreciate the efforts going.
I'm mainly in to Whiskey (but will have to make some Vodka to keep the boss woman happy) so the yield would be minimal using a 10 still, I'm getting a 33l stockpot, even that is on the small side, but to big for my gaff really so can deffo not go bigger

I intentionally went with a bit bigger on the controller so not to push it to its max, only a few € more so what the hell.

The suggestion to bypass the controller during heatup is that just to reduce the amount of work the controller have to do thus reducing the risk of a failure?
I understand what you mean but not what type of switch is needed or how to wire it.

Tack för all hjälp
(Thats just cheers in Swedish, in case any non Swedes are getting paranoid )

[BigSwede]

The suggestion to bypass the controller during heatup is that just to reduce the amount of work the controller have to do thus reducing the risk of a failure?
I understand what you mean but not what type of switch is needed or how to wire it.

Tack för all hjälp
(Thats just cheers in Swedish, in case any non Swedes are getting paranoid )

The bypass does this... The whole idea of controlling the power is to get the output you desire for the given stage of the distillation, and you will probably be using just a portion of the available power. Let's say your line can give you 4KW, the controller, 3KW, the element draws 2.2KW. So you bypass the controller, the element gets its full 2.2KW right from the wall. When your wash is at a boil, you switch in the controller and dial down. You might only need 1KW to get the output desired.

So this way, all the controller ever deals with is 1KW or less. It won't have to work as hard, less heat, less chance of a failure.

It'll probably be fine if you use it full power to get the boil going, but a switch is easily installed. Can't hurt, might help.

To wire it, the easiest way would be to first wire the whole setup as if you'll use only the controller. Then, take your switch, and install it so that it becomes a jumper across the input to the controller when it is ON. That will probably work, but I'd rather see you set it up so that it's an either/or affair; when you turn on the bypass, the controller is completely removed electrically. There are standard wall switches that can act as DPDT, double pole, double throw. I can draw you a diagram if you can't figure it out.

Cheers, good luck.

[Anthoney]

As a standard method of metering power output for all these controllers an ammeter on the input to them will give a linear indication of the watts being used. There will be a small overhead taken by the device you use but apart from that full amps is full power, half amps is half power etc. this works because the heating element has to draw its power from the mains supply and you are measuring current at a point where the volts are constant. So the amps change in direct proportion to the watts being drawn. The resistance of the heating element is nearly constant (it goes up slightly with temp) inductance is slight so ohms law applies.

It seems more natural to meter the values you are controlling, it is nice to see the output volts/amps change as you twiddle but there is a non linear relationship between volts and power. Half volts is not half power. You can multiply the volts by the amps if you meter both to give the actual power but that is a bit harder than a single meter with a direct relationship to power.

Yes you can repeat your run using only an output voltmeter once you learn what to do but you will find it more intuitively obvious how much power you are using with an ammeter on the input side.

You do need tenth of an amp resolution which makes a digital meter easier to use. Each tenth of an amp is 24w if you have 240v mains. So maybe whole amps at 120w each would be close enough for those of you with 120v mains. Or for less than a tenner uk you could use a panel mounted watt meter on the input side and get a direct reading in watts plus it will tell you how much a run costs you when you are done.

[BigSwede]

Anthoney, Q for you, you seem to have a solid grasp of this stuff...

Is there any issue or problem in having an ammeter on the output side? That is where most of them go in our rigs, and to me, I'd rather know exactly how much current is running through the element alone, rather than the entire system. Like you say, unless a controller is getting crazy hot, it's not stealing much in the way of power from the circuit.

I love my Murata meter, it is switchable between volts, amps, and watts, and the latter is truly what matters, what we are interested in.

[Anthoney]

Assuming you are using the justly popular phase angle controller: On the output side you are measuring a clipped waveform which is not what most meters are designed for. They will work but be a bit inexact. A true RMS meter would be exact but is way too expensive for this. Becuase volts and amps are both changing at the same time neither one alone relates directly to the wattage. You have to read them both and mentally multiply them together, still a bit off becuase of the clipping. You could try using a wattmeter on the output but again it may not work too exactly. Measuring the input works with what the meters are designed for, a full sine wave. Hard to say 100% which is the more precise method but I strongly suspect input.

Precision metering is not really that critical though. Many folk manage perfectly well with a numbered dial around the pot and just learn by experience where to turn for each part of the run.

Where it is useful to have a standard system of measurement is sharing information with others to replicate results. One of the hubs of science. I believe it also makes that initial learning period easier and that it is easiest to understand the effect of twiddling the knob if you have a linear reading that relates directly to watts.

Measuring input is probably going to be the most precise you can reasonably get and is the easiest place to get a linear readout; a simple ammeter will do the job.

Because volts and resistance are both fixed here an ammeter IS a wattmeter. You could make your own simple linear scale for an analouge and read the watts directly. I don't expect anyone to do that, there is no need. I am just trying to push the point of what a direct relationship means.

Yes most people measure output becuase the same early designs are copied again and again and it seems the obvious and natural thing to do. You have that very urge right now. I still have it even though I know better. I am resisting, and may yet give in, the urge to also add a cheap £2 voltmeter to the output. Just to watch it change when I twiddle. In this instance though the intuitively obvious thing is not actually the best thing for the job at hand. It can be made to work and becomes entrenched as tradition becuse it just happened to be done that way by the pioneers who were learning themselves and stopped when they had a usable system so they could get on with the real work of making fine spirits. The history of science is full of similar situations. It's human.

Trust me, an ammeter on the input is an optimum for measuring watts easily and cheaply. I spent a few quid more for an actual watthour meter that gives a lot of options besides direct reading of watts, but that is just boyish bling to play with at £8.59 for added toy value. Waiting for it to arrive from China.

If you favour a burst fire controller then twiddling your knob will probably be fairly linear anyway. You won't be able to meter it very easily at all but a watthour meter on the input is your best bet.

I am using these as the heart of my controller.

100a 0-240v phase angle controller. Should stay cool and live long at £10.50. Item number:
190836678049

image.jpg (14.48 KiB) Viewed 4792 times

100a Watt-hour meter Item number:
191219170003

[BigSwede]

Thanks, Anthoney.

I've talked a particular meter up in this forum in a couple of places, because it does accurately measure clipped and other oddball AC waveforms... it's a bit pricey, but the quality is there.

http://www.newark.com/murata-power-solu ... dp/39T1184

Does watts, amps, volts. No idea what "power factor" is.



From the data sheet:

And, unlike conventional, average-responding products, ACM20 power meters can accurately display the real power and true-rms current values of triangle waves, square waves, and other irregularly shaped waveforms, with a typical accuracy of ±1% of full scale.

It's a nice meter. But the reality is, like you say, the only real reason you'd want such accuracy is for scientific purposes, when you've just GOT to know exactly how much power is going in there. For normal everyday use, even a cheap meter will allow for repeatibility, and that's what the average Joe wants.

[Anthoney]

Yes. Repeatability is the main thing. A cheap analogue ammeter on the input will give that. As will other methods people use all the way to a strip of masking tape with pencil marks in the right places.

You would need equally well calibrated heater elements if you really wanted to get uber accurate.

For us it is still useful to be able to say things like "on this boka with a 30lt pot you need 850w while you are compressing the heads" for example. An easy reading of watts, albiet a little bit off, helps.

That meter is a very nice bit of kit and although too pricy for me, for this, it will do the job if you want to use it on the output. The ad really buries the lead; no mention of true RMS anywhere, you have to read the datasheet. Usually that is a big selling point. It is cheap for a true RMS meter.

Power factor is the relationship between the phases of the voltage and the current. A power factor of one is when they are in phase with each other as with a pure resistive load. Inductive or capacative loads throw the voltage and current out of phase. It's why you have power factor correction capacitors on the inductive ballasts of flourescent lights. So the supply meters can read the power used correctly.

[BigSwede]

Power factor is the relationship between the phases of the voltage and the current. A power factor of one is when they are in phase with each other as with a pure resistive load. Inductive or capacative loads throw the voltage and current out of phase. It's why you have power factor correction capacitors on the inductive ballasts of flourescent lights. So the supply meters can read the power used correctly.

Hey, thanks! Finally learned what that little PF was all about. Not that it matters to the distiller using almost purely resistive loads.

Another thing that tends to kludge things up with heating controls is the vast differences between nations when it comes to voltages, and how they are delivered to the average home. The USA system must be one of the worst, IMO. "Standard" voltages have been creeping up over the years. When I was a kid, 110VAC is what you got, and often it was 105 or less. Now if I throw a meter on a wall socket, I'm seeing 125VAC+. And how it is delivered, combining hot leads to make 240VAC, or one leg plus neutral for 120VAC, is goofy IMO.

I'll never forget years ago when I opened my service panel and learned that the neutral wires, white, all terminated at the exact same grounding bar as the green (ground) wires. I understand why it's done this way, but I felt vaguely cheated.

240 VAC standard is just better in so many ways. Half the current needed, less massive wires. You don't have gross voltage drops with long extension cords. I remember running a 120VAC circular saw on the end of a 100' extension cord, and it could barely do work.

Sorry for the rambling. For those with 240VAC standard, enjoy!

[Anthoney]

Yeah it does seem odd when you consider Tesla invented AC in the USA. He partnered up with Westinghouse who was leveraged for the patents by Edison who went on to steal the credit as best he could after his competing DC system failed. So I guess you can blame Edison for the way it was implemented.

Our neutral and earth are separate circuits.

In fairness though, two or more hots can be good because they are out of phase with each other and so deliver more power more of the time. I have a three phase supply that does the same thing. All Tesla. I mostly use single phase 240v. The higher voltage pressure does suffer less from voltage drop.

[sambedded]

As a standard method of metering power output for all these controllers an ammeter on the input to them will give a linear indication of the watts being used. There will be a small overhead taken by the device you use but apart from that full amps is full power, half amps is half power etc. this works because the heating element has to draw its power from the mains supply and you are measuring current at a point where the volts are constant. So the amps change in direct proportion to the watts being drawn. The resistance of the heating element is nearly constant (it goes up slightly with temp) inductance is slight so ohms law applies.

Sorry Anthoney bot it's a wrong assumption. Half amps for the same load means a quarter of power. Same as for voltage.

P=I*I*R
P=U*U/R

[sambedded]

Assuming you are using the justly popular phase angle controller: On the output side you are measuring a clipped waveform which is not what most meters are designed for. They will work but be a bit inexact.

In reality difference between true RMS and regular meter can be very significant - up to 50%

[sambedded]

Measuring input is probably going to be the most precise you can reasonably get and is the easiest place to get a linear readout; a simple ammeter will do the job.

If we are talking about simple phase angle controller or SSVR as on your picture - than it's absolutely no difference in Ammeter placement. At any location reading will be the same.

[Swedish Pride]

It's great to see the wealth of knowledge that we have in this forum, even if it makes my head spin

I just wanted to say thanks to Big Swede for the time taken in explaining how to rig a controller to a element.

I am however not going to use this excellent advice
After getting over the initial giddy excitement of getting stuck in to this hobby I had a think, yup hurt a bit but had to be done.

I just don't have the room to run anything that does not fit on the stove, I would have to run in a very confined space and just not comfortable with the safety of a very confined space, easier to knock something over and break my neck or whatnot.

I'll have to file your advice until I get to build a shed I can run in.
until then I'm mulling over a 10l stove top CM design.

Thanks again

[Anthoney]

Doh! Was overdue a headslapping moment. Of course you are correct that half current is also quarter watts so although still a direct relationship not a linear one.

Yes I know that regular meters can be half off but didn't want people running perfectly workable systems to feel too bad about them. Just to be aware it is not exact.

On that point though. Am I wrong to think this error will be greater when measuring a clipped voltage on the output than a sine on the input? Seems like exactly the situation where a normal meter will be most out. Also as my little electronic wattmeter takes it's power from the feed it too might be happier running on a sine wave. They are supposed to be reasonably accurate on full sine wave mains as they are intended to be a guide to your supply charges.

One thing that does still puzzle me though. I didn't run any numbers, just made a general (wrong) assumption as you correctly pointed out. But... Can you walk me through this one? If the volts in is 240v full sine wave and the volts out is, say 120v clipped sine wave but the current is the same for both with a power factor of more or less one. How can power in and power out both be the same minus a relatively small loss for the rcssrpacvr (just to combine every acronym i've seen applied to these devices)? On first assumption it does not seem to fit although power in must match closely to power out.

[Anthoney]

Ah wait a moment. Is the answer that the controller is only allowing the element to draw power part of the time and so although 240v RMS is present at the input the potential only flows in time with the non clipped part of the output waveform and so input and output are always in balance? The potential at the input is constantly rising and falling to form the sine wave but only actually flows for part of that cycle. I think I finally visualise properly what is happening. A fast on and off switch allowing only some of the waveform to flow. Funny thing is I knew that in words already but only just got the picture of what is (I think) happening moving as a whole in my mind. I can be so slow sometimes. Thank you for making me think harder. Of course I could still be wrong again but I have a little animation in my head that seems to make sense of what you tell me. Its kinda the same as pulse width modulation but at supply frequency and sub waveform pulse lengths.

If I am finally getting it right then I was completely wrong before. Depends what kind of meter you use and how clever it is but simply measuring volts and amps at the input and multiplying them together would be well out when the output was turned down. The meter would draw the full 240v independantly in parallel with the controller while the load was drawing less. The silver lining of having been wrong is learning. That is why I don't mind being wrong when I am. The buzz of understanding something better is bigger than the embarrasment of having been mistaken. I have always enjoyed learning how things work.

[Anthoney]

Thinking just a little bit harder the situation on the input is not quite as dire as it could be. 240v is a bit of an illusion averaged over time. The meter can only measure watts when current is flowing and so the instantanous reading will be current times whatever the volts is at that moment in it's cycle. Not a fixed 240v. It all hinges on the method the particular meter uses and how fast it samples. No doubt Big Swedes meter of choice would good if the project was worth the investment. I'll try mine on input and output just to see what the difference, if any, is. Would be nice to have a true RMS meter to compare to but I can't justify the expense for boyish curiosity when the truth is anything repeatable will do the job. If I was a bit wealthier I think I would though.

[Odessit]

Hey there.
My latest development - a device to manage of our processes, with adjustable stabilized heating element controller with Bresenham's line algorithm.
For setting of desired percentage of the heating (eg, 43%), device gives (sends?) To heating element 43 periods of the mains voltage of the each hundred.
My device mesures voltage during each "working" period, and if the mean value is not equal to the nominal, the device adjusts amount of "working" periods so that the heating power equals desired percentage.

The device can measure the temperature at two points and can to control two solenoid valves, water and alcohol, and has an input for connecting a sensor of "wet floor", or "full bottle", or something other.

Trials start in a few days, when i finish "polishing" of algorithm and kill all bugs.

[ET_Racer68]

Newbe here, just was wondering if a 120v 1500w element could be controlled with this.
http://www.ebay.com/itm/LED-Display-AC- ... 3cddeef746" onclick="window.open(this.href);return false;" rel="nofollow

I have read a lot of the pages here, but I'm up to late again, and you know how the brain works, when in need od sleep.
I have parts on order to build a SSVR controller.

[ben stiller]

we have been discussing this on another thread. That is most likely a digital controller and there is a thread or two about
how they don't work with heating elements. I know the display looks cool but not absolutely necessary. Go with the analog
one to be safe. I use this one on a 4500 watt element.

http://www.ebay.com/itm/10000W-220v-Adj ... 2c7271bb5a

[BigSwede]

Agreed with Ben, there. Those 10 kilowatt controllers do work OK, lots of guys have success with them, but lose the digits. You'll save money, too. And add a voltmeter across your heater element lines, a simple analog volt meter will cost $6, and is easier to install than an ammeter. That will allow you to track and log your processes, so future runs with the same wash can be accurately repeated.

But if you have zero stuff on hand, and you have a few extra $$, I recommend the potentiometer controlled solid state relay for heat control. You literally have two components, the relay, and the potentiometer, plus some wire. Of course you can fancy it up with meters, lights, switches, etc. Get a relay maybe 2X your expected load, so if running a 5500 watt element at 240 volts (23 amps) - recommend a 40A or higher rated SSR. It'll stay cooler, last longer, and won't be more than a couple bucks extra.

[ET_Racer68]

I do have a 40A SSVR, and pot, plus 120v, 50 CFM fan, 30A switch, and a cheap, volt/ammeter, ordered. The box to contain it all was the most cost. I now have a 1500w/120v element in a 8 gal boiler, and it has plenty of power. I do need a control to control the amount of flow. It runs faster then I like for a finished product. I now have more of a small stream, then dips.

I run in the basement now (to cold, outside or garage). My next question is, will a 5500w wired for 120v, give enough heat. I have 220v near in basement, but not the garage, for summer running. I don't want the cost of 10 gage wire to put 220v in the attached garage. I now have 2, 20 amp, 120v circuits. I'm in deeper, then I thought already in this new hobby.

[still_stirrin]

ET_Racer,

V^2/P=R, and since your heater's element resistance is a constant:
(240x240)/5500=(120x120)/P
P=1375 W, and that's with 1375/120=11.46 amps.

It's a long way from the 5.5kW you're used to running. It would be enough power to run your still in reflux mode. But you've got a pot still. So, I'd think you would want a little more power, especially to heat the wash to boiling.

Now, if you had two of those 5500 W elements running, you might be happier. But I doubt your boiler has two heat element ferrules.

I think adding the 220 circuit to your garage is a wise investment. Unless you'd prefer to run from the basement year round (not such a bad idea anyway).
ss

[ET_Racer68]

I do have a electric stove that is on the same wall as the attached garage, it is 220v 30a. I could mount a junction box and go through the wall to the garage, and have it in the garage also. Just can't run the stove and boiler at the same time. What yah all think? My service is of course 50' on the other end of house.

[ben stiller]

Sounds like a great solution but I would encourage you to put in a cutout switch so no one accidently turns the stove on
and overloads the circuit. I pull out the drawer under my range and plug into the stove outlet. I store my controller in said drawer.

[ET_Racer68]

I live alone, so no problems there. My Lady still has a 28 yr old son at her home, that doesn't seem to be getting off his butt to soon. It works better that we live apart, If I say to much about her son, it's like waking up a momma bear with cubs. I'm 58, and moved out with a job when I was 18. From being a paper boy @ 12yrs until now, never been without a job.

[still_stirrin]

I do have a electric stove that is on the same wall as the attached garage, it is 220v 30a. I could mount a junction box and go through the wall to the garage, and have it in the garage also. Just can't run the stove and boiler at the same time. What yah all think? My service is of course 50' on the other end of house.

Definitely!
The "failsafe" switch that ben stiller suggested is also a good idea, but not absolutely necessary because your dryer circuit is protected by a breaker. If someone inadvertantly turned on the dryer while you had your still on, it would likely trip the breaker which would immediately notify you by shutting off the power to your still (which is where you'd be watching, right?).
But you do want to use at least 10 gauge (8 guage, even better) wire for your 220V drop to the garage, from the dryer j-box.
ss