Heating Element Control

[pintoshine]

My hot plate cycled even when on high. When I went electronic control, I just wired a jumper across the existing control. I know that the overheat was there by design but it really was annoying to have it go off for 30 seconds after only being on for 15. I also had to wire across the protection fuse because it went as soon as I got it to stay on full time. So not mine is just a burner with an external heavy 120vac dimmer control. I used the same circuit as the kit but replace the pot with a 250k instead of the 500k.
One was talking about finding a diac locally. I could not find any but I'll send you a couple if you need some. They are real cheap from Mouser.com The ones I have can trigger a 8 amp alternistor but not the 40 amp one directly.
That is why I use the cascade.
I think I have an update schematic of the kit's circuit. I'll post it too.

[CoopsOz]

Pint, I finally built your controller that you sent me some months ago. I'm yet to test it under load but with a voltmeter across it, it goes between 238.0VAC (minimum) and 250.6VAC (max). Is this normal? Do I have anything to worry about? Do any of the other Aussies who have built one of Pint's control's have different readings? It would be appreciated if someone could measure the output for me. Thanks, Coops.

[pintoshine]

yes that is normal because it is changing the wave form. Th volt meter is not enough a load for the circuit to operate. Unless you have a really good volt meter with integrating true rms measurements it won't tell you the correct voltage.

[CoopsOz]

Thanks Pint.....that was quick!

[glassman]

found most of the parts for the control pint. the diac is in question. any part # or info? want to get my glass still runnin and thats the last thing i need. gman

[rad14701]

found most of the parts for the control pint. the diac is in question. any part # or info? want to get my glass still runnin and thats the last thing i need. gman

This unit could also be built using a quadrac which is a triac with a built-in diac... Additionally, you can use a sidac in place of a diac as long as it falls within the same specification range...

[glassman]

hate to guess rad but here goes. as long as the components can handle 220v @40amp they should work. it's all the other specs when buying components that screws me up. millivolts, leakage, you name it. mouser has way too much info for this brain. like to keep the learning curve as flat as possible. but i'l try a few options. pint is out of stock or i would just buy his kit. i'll be firering a 4000w heating mantle i built for a 22L flask. have a digital watlow temp controll but it will put all 4000w on the flask untill temp is reached. don'y want to stress the flask quite yet. too expencive to break thanks, gman

[rad14701]

hate to guess rad but here goes. as long as the components can handle 220v @40amp they should work. it's all the other specs when buying components that screws me up. millivolts, leakage, you name it. mouser has way too much info for this brain. like to keep the learning curve as flat as possible. but i'l try a few options. pint is out of stock or i would just buy his kit. i'll be firering a 4000w heating mantle i built for a 22L flask. have a digital watlow temp controll but it will put all 4000w on the flask untill temp is reached. don'y want to stress the flask quite yet. too expencive to break thanks, gman

Not to throw this thread off-track, but some minor explanation is in order... The schematic presented above is based on the theory of using a sensitive triac circuit to drive a high-power triac... That being said, the circuit presented is actually over-spec'd on the sensitive side, but adds a good margin for error...

Now, regarding the spec's for alternate parts... A 600V 6A quadrac could be used in place of the diac and triac listed... It would go into the circuit in exactly the same manner, only without the diac... You try to keep all components in a circuit of the same voltage level if at all possible... For 240V circuits you would generally use either 400V or 600V components, and this circuit uses 600V parts... For 120V you would use either 200V or 400V components... You, essentially, double the expected input voltage when rating components...

Sorry if I deviated the thread...

Note: All of the light dimmers I have used have incorporated a quadrac...

[pintoshine]

from mouser the diac part number is 511-DB3TG
http://www.mouser.com/Search/ProductDet ... I12A%3d%3d" onclick="window.open(this.href);return false;" rel="nofollow

[pintoshine]

This circuit is not overly sensitive like you said. The 40 amp alternistor requires 4 amps gate current at full load. That is why the 6 amp driving it. The 6 amp only require a few milliamps and the resistor can supply that without becoming under too much load. The resistor wattage is the limiting component in the trigger circuit which is only 1/2 watt. At low position which is 500k ohm it is only able to supply 68 microamps at the peak voltage swing.

The rms voltage of a 240vac is 240vac rms. This means that being sinusoidal the area under the voltage curve was integrated and give the same power rating as if it were an equivalent dc circuit at 240dc.
To get the real peak to peak voltage you must divide the rms by root 2 over 2 and this gives approx. 340 vpp. This is too close to 400 v so I usually choose 600 or 800 v components. This derating helps them last through voltage spikes.
Also, being the 40 amp alternistor can handle 40 amps continuously, I chose that to actually handle 20 amp loads because of the 200% derating for current allows it to be more reliable in the long term. Besides the expense of the larger components is not proportional to rate values. They are only nominally more expensive.
I technically don't use triacs because of their problems with fals triggering without snubber circuits. The alternistors won't conduct in the 4 th quadrant so they always go off dependably eliminating the need for a snubber circuit.
I know a bunch of technical garbage.

[rad14701]

That "technical garbage" is what keeps the "Average Joe" from having a run come to a premature end with no way to finish up... I've spent several evenings working on some spreadsheet calculations to help me figure some of that "technical garbage"... Sometimes, even when you understand it, it still looks like garbage...

[HookLine]

Sometimes, even when you understand it, it still looks like garbage...

Ain't that the truth.

[glassman]

this has been one of my favorite threds. thanks for the info and help. will build the circuit this weekend and post pics on the completed gigundus glass pot still/ fractioning still/ extraction apparatus. man this is fun! gman

[glassman]

built the control today and it works great. don't know why it works but thanks pint. gman

[CoopsOz]

I concur, I ran one of Pint's kits today for the first time and it works great. I didn't realise the level of control it would give me, the smallest turn on the pot registers. Thanks Pint, I wish I had of bought one initially instead of blowing all that cash on dimmer switches etc.

[VictoryRay]

thanks alot pint for all your help!!

i stopped by lowes on my way home from work and got everything i needed from their, and i just got done ordering the resistor and triac from mouser.

its kinda weird for me to be ordering electronic parts since im a fabricator/welder, but hey, im always up for a new challange.(and if i cant get it figured out, ill get a kit from you.HAHA)

btw, im going to use the very first drawing pint posted, and ill keep you all informed on how well "I: can let the smoke out of it....

[VictoryRay]

alright, if anyone is having any concerns about putting together one of pints element controllers: DONT WORRY!!! i think i am probably one of the least electrically savy people ever, and i actually made a controller that worked(on a shop-vac so far).

my original idea was to have pintoshine make one for me, but for the cost of the parts i figured i could at least try to let the smoke out of a couple.

thank you pint for being busy , and for taking the time to walk all of us un-electrically educated people through the steps.

now i just need some instructions on re-wiring my hot plate.

thanks again!

[CoopsOz]

Mine is now making some pretty funky noises, kinda like something is vibrating. It still works though, should I be concerned?

[rad14701]

Mine is now making some pretty funky noises, kinda like something is vibrating. It still works though, should I be concerned?

Every controller I have built, regardless of the design and related components, has made buzzing or singing noises... This is normal for circuits with a bare minimum of components... You might want to be careful as far as having certain electrical devices close by during testing and operation, like hearing aids, pacemakers, or live explosives detonators...

[Jippe]

Can I use BTA40-600B & BTA06-600B triacs instead of Q6040j7 & Q6006k6 and 25w 68ohm resistor instead of 75ohm?
How much current goes through potentiometer?

[hllrsr]

Pintoshine,
Is the effect on the heating element linear, or does it get into the effect of half the voltage, quarter the wattage?

hllrsr

[ebo]

Guys..the information you all have posted is excellent. All I had was an idea of what NEEDED done but didn't know where to start. Thanks! Anyway... I built the control that the schematic shows and works excellent. I put an amp clamp on one of the leads and it controls the current in tenth amp increments (+-1) from 11.7 amps to 4.6 amps, this, with water control, offers total temperature control. The only change I made was that I used an ceiling fan speed control switch but it basically the same thing. I used some old hinksinks off of computer processor chips for cooling the arcol and the triac. (Just a note, I messed up and mounted one of them the wrong way. To get the best cooling, as some inthe post already stated, they should be mounted with the fins running vertically. I took an keyboard/mouse switching box and mounted the components in it and also put plugs on the leads so I couls just plug the heating element into it. It requires a little design work because one lead goes directly from the female plug to the male. Here is some pictures. I left the cover off for the pictures but it does have one. Thanks again everybody! I hope I contributed just alittle too.

Ebo

[snuffy]

The initial question about router speed controllers sort of got blown off.

I've used one for several years to control 1) a 1500W hotplate and 2) a 1500W immersion heater. They work OK. Mine runs pretty warm, but it has stood up well. It is rated and fused for 15A at 120VAC.

These are frequently on sale for around $20US at Harbor Freight (cheap online tool seller).

So the short answer to the initial question is YES.

Variacs / autotransformers also work well. This is what is usually used in labs for controlling heating mantles. MPJA.COM has 20KVA ones for $105US plus shipping. They weigh 22 Lbs so freight is around $20-$35 in CONUS, depending where you are. The big advantages are they have a voltmeter so it is easy to figure how many watts are being used; they will increase the voltage up to about 130VAC; and they are flatly linear so the calibrated dial is pretty darn accurate.

Another alternative is to use DMX lighting controllers. These are digitally controlled lighting dimmers used in showbiz. I have several I use for controlling projectors in light shows. I picked mine up on ebay for $35US - $75US and a very fancy control board for $130US. The low end ones usually have four circuits and will handle up to 20A at 120VAC. They are very precise, use a special 3-wire serial protocol and there are USB-to-DMX converters available for around $50US - $80US. These might be a very good bet if you are looking for building a computer automated setup.

[seravitae]

how much would people pay for heating element controllers? seeing how many people here having a rough time getting them, im considering making a small run of my own, if it's worth my time.. cost/wattage?

[silaflex]

Yes, I may be interested in one.

Just wondering if anything is wrong with using these I have found? The 4th one down controlled by a 500k pot. Would be easier to wire up. http://www.oceancontrols.com.au/relays/ ... ch_ssr.htm" onclick="window.open(this.href);return false;" rel="nofollow

Pros cons anyone?

[rad14701]

Yes, I may be interested in one.

Just wondering if anything is wrong with using these I have found? The 4th one down controlled by a 500k pot. Would be easier to wire up. http://www.oceancontrols.com.au/relays/ ... ch_ssr.htm" onclick="window.open(this.href);return false;" rel="nofollow

Pros cons anyone?

According to the spec sheet it appears that an SS-225VA or SS-240VA would work fine with either a 250K or 500K potentiometer and adequate heat sink...

[Dnderhead]

I don't thank a "pot" for that is cheep better check first before buying

[seravitae]

Yes, I may be interested in one.

Just wondering if anything is wrong with using these I have found? The 4th one down controlled by a 500k pot. Would be easier to wire up. http://www.oceancontrols.com.au/relays/ ... ch_ssr.htm" onclick="window.open(this.href);return false;" rel="nofollow

Pros cons anyone?

Yes, you should work out whether phase trigger control means - and see if it has anything to do with zero crossing. If the device does not do zero-cross detection you will introduce lots of noise into your electricity line... not good.

[seravitae]

Even if i dont commercially develop my heat controllers, would anyone care to list any 'wishes' they'd like to see in a heating controller?

My next controller will have a display which lets you set/save different "mash ramps" - the controller will have immersible temperature sensors. The controller will bring up the temperature of the mash to a tempearture of your choice, and hold it there, before moving on to the next temperature in the ramp. So you can have a ramp for different grain batches and just hit go and it will do glucan, protease, alpha/beta amylase rests, all for you. It will also turn a stirrer on at the beginning of the mash ramp, and off at the end. I want to implement this feature because that way you can schedule a time on the device to start mashing for you, and when you wake up, it's ready for human intervention. (im also implementing this for pre-heating washes for distillation. nothing beats going to bed and waking up to a 60-70C wash ready to go )

the device will have a number of temperature sensor inputs and allow you to choose which one should be used for feedback in the system, or you can average them all - having a few tempearture sensors up the side of the mash tun. you will be able to see all the temps on the display when mashing/distilling.

in distillation mode the power will be manually throttled by the user, or you can also set a program like the mash ramp. I will also add a small relay for controlling a cooling pump. why? because i am thinking of making a still with dual pumps. one for potstill condensor and one for permanent inline reflux condensor. That way you can bring it up to temp on potstill mode, and then collect your fraction at reflux mode if you want. (i know some people do this).

So what other features would people like to see in their dream controller?

oh ps. i may also include a capacitance sensor array so you can see the liquid level inside in the still/tun.

[punkin]

If it's cheapish, reliable and works on 240, i'll buy one. Sounds just the thing for my mash pot, put it in of an evening and pitch gluco in the morning for dumping in the fermenter after work.