Heating Element Control

[rabs72]

Well guys have read all of your post and the best thing that I have come up with is a motor speed controller and that is a small kit that can be built.

You have a 12v power supply in and that can control a Soild state relay to rapidly switch the element on and off



http://www.jaycar.com.au/productView.as ... rm=KEYWORD" onclick="window.open(this.href);return false;" rel="nofollow

http://www.jaycar.com.au/productView.as ... rm=KEYWORD" onclick="window.open(this.href);return false;" rel="nofollow

have compleated the kit it works as required. tested it via a LED as an LED will not dim at all in effect i was raipdly turning it on and off.

so there are couple more things to do for it as I am going to also use this unit in a Magnetic stiring rig to I will house it seperatly and have the output to another box with the SSR in it and the Mains in and out.

Will work quite nicely and simpley too.

just a bit of simple soldering work and presto it works.

[maheel]

rabs72 that relay you linked to seems to be 12V DC and is it a SSR?

how are you going to run a heating element off that on 240?

i did not think it would work but rally i have NFI in regards to electronics....

[kiwistiller]

As well as my triclamps haul at the scrappy today, I found a DC motor controller. Input is 240V, 16A. Am I right in thinking that this would be an ideal still controller?

[snideman]

As well as my triclamps haul at the scrappy today, I found a DC motor controller. Input is 240V, 16A. Am I right in thinking that this would be an ideal still controller?

Hello kiwi,
This has been discussed in-depth on page 1. Motor controller = high inductive loads - shine rigs = high resistive loads(element). Ideal still controller = PSR-25.

[rabs72]

rabs72 that relay you linked to seems to be 12V DC and is it a SSR?

how are you going to run a heating element off that on 240?

i did not think it would work but rally i have NFI in regards to electronics....

http://www.jaycar.com.au/productView.as ... rm=KEYWORD" onclick="window.open(this.href);return false;" rel="nofollow

I put up the wrong link with it.

The one above is the correct one.

Well at the moment I am running a 3600w element and it works fine.

The boiler is fine with it. I just need to be able to control the heat out put.


What the function of the controller is is to turn it self on and off very quickly and that is what it will do with the SSR and in doing so control the time that the element is on and reduce it power output but not draw the full power. With reduceing the wattage of the Element to. ie instead of a rapid boil more of a genteal boil/simmer.

Will finish of over the weekend and test.



It is exactly the same function as a dimmer as I i said when I tested it.

The function of it is what is stated here in http://en.wikipedia.org/wiki/Pulse-width_modulation" onclick="window.open(this.href);return false;" rel="nofollow

and I believe it will function correctly too. simple and cheapise way to mak it happen.

well i will see

[squidd]

As well as my triclamps haul at the scrappy today, I found a DC motor controller. Input is 240V, 16A. Am I right in thinking that this would be an ideal still controller?

Kiwi, your post reminded me that I had a DC motor controller, stashed away and forgotten.
Yes, it should work. The element would be connected across the ARM terminals.

If you like, I'll hook it up in the next couple of days and let you know.

squidd

[squidd]

Kiwi,

Just hooked up the DC motor controller (Wood's E-Trol +) to an incandescent light bulb and it worked quite well.

The maximum DC output voltage is somewhat lower than the AC input voltage, 195 volts vs 230 volts; I suspect this means that the unit won't quite deliver full power.

The bulb started to glow with the control pot at 20 on a scale of 0 to 100, and the light intensity variation was smooth and linear.

HTH,
squidd

[kiwistiller]

Thanks!

[MuleKicker]

rabs72 that relay you linked to seems to be 12V DC and is it a SSR?

how are you going to run a heating element off that on 240?

i did not think it would work but rally i have NFI in regards to electronics....

http://www.jaycar.com.au/productView.as ... rm=KEYWORD" onclick="window.open(this.href);return false;" rel="nofollow

I put up the wrong link with it.

The one above is the correct one.

Well at the moment I am running a 3600w element and it works fine.

The boiler is fine with it. I just need to be able to control the heat out put.


What the function of the controller is is to turn it self on and off very quickly and that is what it will do with the SSR and in doing so control the time that the element is on and reduce it power output but not draw the full power. With reduceing the wattage of the Element to. ie instead of a rapid boil more of a genteal boil/simmer.

Will finish of over the weekend and test.



It is exactly the same function as a dimmer as I i said when I tested it.

The function of it is what is stated here in http://en.wikipedia.org/wiki/Pulse-width_modulation" onclick="window.open(this.href);return false;" rel="nofollow

and I believe it will function correctly too. simple and cheapise way to mak it happen.

well i will see

rabs,
your kinda right. PWM will work.... kind of. It needs to be a Phase angle controlled, so it is timed with the frequency of the AC line. if you have 60hz ac, thats 60 cycles per second. Your PWM complete cycle time (on time+ off time) needs to be a multiple of 60 to get accurate control. And you need to use a radom or burst fire SSR, not a zero cross relay. Cuz even if your PWM commands off, a zero cross will not shut power off until the wave crosses the zero mark.

[Odessit]

It needs to be a Phase angle controlled,

Yes, of course. And Phase angle can be controlled with PWM regardless of frequency of AC. I use 1000 - 10000 cycles PWM per second for control circuit 50 Hz. There are special chip KR1182PM1 for it.

Phase angle depends on level of charging of capacitor C. A chip tries to charge him through resistor, and optocoupler tries to discharge him with PWM - mode. So frequency of PWM can be any and does not depend on frequency of AC.
A capacitor takes а charge from chip while the transistor of optocoupler is closed, and discharges while transistor is open. Therefore level of his charging (voltage), and phase angle after triack for our loading can be easy controlled by PWM.

[Centar]

After reading here about how to make a high power controller from a common household dimmer (Pinto's circuit), and seeing the MAJOR mistakes in the design I had to tell you all here the BEST and easiest way of doing it. (using my 30+ yrs electronics experience)

The basic idea and circuit is correct BUT the dropping resister is WRONG.
Most of you have noticed that it doesn't get hot or even warm and one guy (Snuffy) even hooked a light in series with it (great idea) but to no avail BECAUSE the amount of current going through it is about 10 ma. TRIACS need very little current to switch on, just check the data sheet for the TRIAC I used...a much larger resistance and smaller power rating is needed here....

The best TRIAC to use can easily and freely be scrapped from a larger type microwave oven (got half a dozen this way myself from discarded microwave ovens) or purchased for as little as $2 on ebay.
Mine was marked TG25C40.
This is a 25A unit rated at 400 volts good for up to 3000W at 120vac and should work for up to 6000w at 240 VAC.
It has a large 2 hole mounting for better heat transfer, spade/solder terminals, and an insulated mounting for simplicity of mounting/heatsinking.
I used one of these Triacs for a 1500w 120vac controller. So the design for double rule works good here.

As for the light inline/replacing with the dropping resister idea, this is perfect for many reasons BUT was flawed in that not enough current was present to light the bulb...To fix this I used 2 LEDS connected in parallel in reverse polarity. They do not shine as bright as they could so use bright white ones (got mine out of a dollar store light). The LEDS have to be of the same type and color to keep the switching of the TRIAC symmetrical. AND yes 2 are REQUIRED connected in PARALLEL and REVERSE polarity to each other as this is AC we are dealing with and LEDS are diodes after all...
This Light serves as a ON light, a indicator that the dimmer is working (as it gets a little dimmer on the highest setting), and as a load tester (will not light if there is no load connected, ie. if your boiler is not connected or burned out)

AS for the Dropping resister a 1K 1/4 watt proved to be the perfect value for 120 VAC. YES that's 1000 ohms at 0.25 watt
This can be scrapped out of most any piece of discarded electronic equipment (color code: brown - black - red as the 1st 3 colors) or purchased very cheaply.

Any cheap dimmer (300 or 600watt) will work and connecting 1meg 1/4 watt resisters (color code: brown - black - green) across it's pot until the dimmer just comes on at its lowest setting gets rid of the hysteresis of the dimmer and gives a expanded range to the dimmer control. (mine used 3 1meg resisters, so a 330k would have been good by itself)

Both the LEDS and the resister should be mounted on the dimmer (the LEDS connected in parallel but reverse polarity to each other and in series with the 1k dropping resister), the LEDS are easily mounted in holes drilled in the mounting plate and pushed through from behind and crazy glued in place. This keeps all the parts on the dimmer except for the TRIAC which of course should be mounted on a heatsink with thermal compound for good thermal transfer. (I saw alot of posts about a substitute for thermal compound, some crazy ideas, BUT the stuff is just ZINC OXIDE and silicon oil to keep it from drying out, You can find a substitute right in your medicine cabinet or drugstore as an ointment)

I have built and tested this under load and it works perfect so will house it all in a pretty box, etc and upload some pics here...

Hope this helps clarify and simplify this a little...

[rad14701]

Centar, we'd love to see pictures and a schematic... Sounds like an interesting option for a dimmer and triac based controller...

[Centar]

Ok here are the circuits, I modified Pinto's schematic and included one for the optional mod to the dimmer.

I'll get some pics up soon showing how to mount it all on the dimmer plate.

[Pooyan]

Hi Centar,

I've build a power controller according your modified schematic, (instead of the microwave triac i use a BTA16 700B and a 300W 220V dimmer) i want to hook this up between my preservation boiler which has a 1800W element and uses 220/230V.
The boiler is thermostat controlled, but i simply turn the nob at the max. setting to override it so it doesn't cycle.
For stripping/pot still runs the max power is oke, but i want less power on a spirit run.
I've done a little test with the powercontroller but before i throw numbers here, note that the element's 1800W stated on the manuf. label, is in fact 1640W (measured with and without power controller connected to boiler)

- On the lowest setting (dimmerknob turned completely to the left) output is 1040W, the 2 leds are blinking
- dimmerknob turned right just at the point that the leds are not blinking anymore but give constant light, output is 1190W
- On the highest setting (dimmerknob turned completely to the right) output is 1640W

I noticed the schematic is made for 120V, do i need to change something for use with 220V?
I have not done the dimmer mod yet, wanted to hear your input first...

Pooyan

[crazyk78]

Might not be a linear pot in the dimmer.

[rad14701]

Pooyan, you might need to experiment with the resistor value between the LED's and the dimmer in order to get better low end control... Try increasing the resistance... I'm guessing that you're getting to full power before the dimmer is turned all the way up...

[Pooyan]

@ck, don't know if it's a linear type pot, housing of the dimmer seems not constructed to easily replace parts inside, think i can only open it by using brute force.

@Rad, i will give your suggestion a go, by head, i think you might be right with the output beeing at full power already before the max position of the dimmer is reached.

Will do some testing and let you know the results, got to get me some diff. resistors first...

Thnx,
Pooyan

[Centar]

Pooyan, what kind of LEDs did you use?
After reviewing the specs for the TRIAC you have used it appears as though that particular TRIAC needs a little more triggering current then the microwave variety, thus you may have to reduce the resister value to maybe 500 ohms and you may need to double up the LEDS as they are only going to give about 20ma current and you may need double that. (put 2 of the LED circuits in parallel not series)
The LEDs should never "blink", but should get a little dimmer on the highest dimmer setting.
You could also try to switch around the 2 wires from the dimmer (this can make a difference depending on the dimmer circuit)
Most dimmers are contained in a plastic BOX that is riveted to the mounting plate, drilling out these 2 rivets is easily done to access the parts.
As for the POT being LINEAR, it more than likely is as the other type is LOG and for audio use mostly.

[Pooyan]

Centar, the leds are the "bright white ones", the leds are only blinking on low setting (1040W till 1190W), from 1190W till 1640W constant light which gets dimmer if they reach the high setting...

Ok, i will proceed step by step, starting with swapping the 1K resistor for a 500 ohm one.
Have to check for some left over PCB's in my drawer to pull some off....

WoCo time now.....Cheers!

[Centar]

Pooyan, don't forget to try to switch around the dimmer wires and after thinking about your symptions it is possable that RAD is correct and a 2000 ohm resister might stop the blinking (which shouldn't happen) So try 500 and 2000. I orignally determined the value using a 5k pot and found that 1k was a fairly normalized value for the circuit, you could try the same for an experiment.
This also may be due to a atypical dimmer circuit. If all else fails try a higher quality 600watt model. (it shouldn't make any difference as we are drawing less than a watt through the dimmer)
Please keep us updated on your progress/results as I cannot duplicate your problems myself and you may find something not thought of yet...

I have also found that the TRIAC gets its hottest on the highest (full on) setting, this is a waste and a switch wired to bypass the TRIAC is best used for full on power (100%), this would keep the TRIAC stone cold and give the best efficiency. Not a necessity, but can help in some circumstances.

[Pooyan]

Centar/Rad,

I've done some tests, first i have switched the dimmer wires, that didn't made much of a difference.
After that i tried different resistors to replace the 1K one, i ended up with a 10K resistor that functioned well, off position was indeed completely off and the LED's where not flickering but gave constant light during the whole range, bit less on full power.

I have mounted the triac on a old processor coolingblock, cooled by a fan, works great.
without the fan blowing while the controller is in max position, even for a while, the LED's will start flicker again in the off position and the controller passes through quite an amount of Watts instead of zero. Less problems of course with a larger coolingblock, but i had it lying around and this setup works for me, i will only use the controller on a spirit run.


Guys, many thanks for helping me out, hope this will help others while building a 220V powered controller based on Centar's modified circuit...

Pooyan

[Centar]

Congrats Pooyan on getting your controller working and thanks for the 220v (240 in north america) info...

I think your controller is staying on because your overheating the TRIAC as it seems to work correctly when kept cool.
Continued use over rated temps will lead to "thermal migration" within the TRIAC ending in the TRIAC being always "on".
This is what happens to the light dimmers when overloaded/overheated when running too many lights.

Proper heatsinking is a necessity! As a general rule, the TRIAC should never be allowed to get to hot to touch with your fingers...

[rad14701]

Do you guys have spec's on the LED's you used for your builds...??? I'd like to give this design a go with 120V, and perhaps in 240V as well...

[Pooyan]

Rad, i used the following LED type: L-5WCN/5

5mm
20000mcd
3.2V
5-20mA

[Centar]

RAD,
The exact type of LEDs doesn't matter as long as they are exactly the same.
The bright white variety are the best for illumination of a externally mounted colored lens or direst viewing.
These can easily and cheaply obtained from a dollar store flashlight (I bought one for $2 and it had 24 of these LEDs)

[still crazy]

Do you guys have spec's on the LED's you used for your builds...??? I'd like to give this design a go with 120V, and perhaps in 240V as well...

If you do RAD please post I am getting ready to make the plunge on a controller and value your expertise.

[rad14701]

RAD,
The exact type of LEDs doesn't matter as long as they are exactly the same.
The bright white variety are the best for illumination of a externally mounted colored lens or direst viewing.
These can easily and cheaply obtained from a dollar store flashlight (I bought one for $2 and it had 24 of these LEDs)

I would assume that the LED's would have to have a rating of some type, otherwise folks would be attempting to use under-rated LED's and wondering why their controllers don't work... They have to allow enough current for the circuit to work, but not so small that they fail under load... This may be why your circuit and Pooyans required different resistance... I have a parts box full of miscellaneous new LED's but I'm not sure they would hold up under a 120V load... The PN provided by Pooyan at least gets me in the ballpark...


@still crazy

I'll be making a 120V controller first, so I hope that's what you're looking for... I don't have easy access to 240V here in my apartment... Have I stated recently that apartment life sucks...???

[Centar]

The LEDs have to be EXACTLY the same, same type and same color.
This is because LEDs of different colors and types have slightly different operating voltages, which in this circuit will cause NON-SYMETRICAL switching of the TRIAC which will cause alot of interference and buzzing noises in equipment plugged into the rest of your house.
So this is why they NEED to be the EXACT same, so the positive and negative parts of the 120 VAC waveform are switched on at the exact same time by the TRIAC = symetrical switching.
The type doesn't matter much in this circuit (most typical LEDs will work here) and the LEDs usuall wont receive full operating voltage (typicaly around 2 volts) so they may appear a little dimmer than should be. Thus the sugestion of bright white LEDs, to get the most light from them as possable.

The fact that the circuit is switching 120 VAC or 240 VAC has no bearing on the LED ratings as they do not receive even full voltage/current in this application.

I should have the easiest and probally the best way to house and build this unit up in pics soon if you want to wait a bit for that...

ONE LAST thing I have noticed that of every internally heated pot and all the homemade controllers NO ONE talks about one VERY IMPORTANT point: GROUNDING!

All metal boilers with internal heating elements should be grounded.
All power controllers should be grounded. Enclosures as well.
Simply put Everything of exposed metal including the column/head, boiler, controller, etc SHOULD ALWAYS BE GOUNDED and plugged into a properly grounded outlet.
Considering that alot of setups are connected to the water system (which is grounded) for cooling and that it is a "wet" hobby involving liquids (High electrocution hazard) GROUNDING is a MUST!
Be safe....follow UL / CSA , etc standards and the old electronics rule "GROUND UNTIL IT HURTS" or was that sheild until it hurts?....no matter , same importance.....

[still crazy]

Yes RAD I have both but want to just go the 120v route
Put a 1500 watt element in my SS extinguisher and want to be able to control the puppy

[Kentucky shinner]

what is the thread size of the coupling you used to screw the element into...?