Heating Element Control

[Dnderhead]

http://electronics.shop.ebay.com/Electr ... ors&_rdc=2" onclick="window.open(this.href);return false;" rel="nofollow

[MuleKicker]

Wow, that's some amazing work mate.

What's the brains in that contraption?

2 RTD temp probes going to 2 Watlow 96 series temp controllers. The top controller reads my collumn temp and if it gets above the set point it turns the bottom controller off. and you guessed it, the bottom controller runs the relay. The bottom controller reads the boiler temp, just for the hell of it. I can judge pretty well how long a run is gonna go based on what the boiler temp is when the collumn temp jumps up. The bottom controller is setup for 4-20 milliamp output to run a 25A phase angle control relay. If you google "watlow 96" you can come up with the base temp controllers fairly cheap. There is a ton of programming options in these things.

[rad14701]

I really like the way your controller project is turning out... You just may have a winner there...

[Bob421]

http://electronics.shop.ebay.com/Electr ... ors&_rdc=2

Thanks. I don't know why but I never think of eBay when looking for that kind of stuff.

[Pamulli]

As I mentioned in my PM reply to you, your dimmer uses a double time constant circuit which is better than the cheap dimmers which use a minimum of components... I'd try using the circuit in my previous post considering the added circuitry... The worst you can do is to scrap a dimmer - something many of us have done at least once...

Well I finally got good welds and was able to try my switch and it worked. I used the dimmer as is like you suggested Rad. I don't know if it will have a shorter lifespan because of the 240V, but so far no sparks or smoke . I've only heated water at this point, but it brought it to a boil and turning it down lowered the temp below boiling so it seems to have a descent range. I'm interested in seeing how easy it will be to fine tune the temp for a real run, but it will be a little while before I have time to get a batch going. I'll take some pictures and post my parts list for anyone interested.

[Bob421]

As I mentioned in my PM reply to you, your dimmer uses a double time constant circuit which is better than the cheap dimmers which use a minimum of components... I'd try using the circuit in my previous post considering the added circuitry... The worst you can do is to scrap a dimmer - something many of us have done at least once...

Well I finally got good welds and was able to try my switch and it worked. I used the dimmer as is like you suggested Rad. I don't know if it will have a shorter lifespan because of the 240V, but so far no sparks or smoke . I've only heated water at this point, but it brought it to a boil and turning it down lowered the temp below boiling so it seems to have a descent range. I'm interested in seeing how easy it will be to fine tune the temp for a real run, but it will be a little while before I have time to get a batch going. I'll take some pictures and post my parts list for anyone interested.

Glad to hear you got it going. How are you dealing with the heat of the triac?
I made another run this weekend and am concerned with the heat buildup in my aluminum outdoor 2gang box. I put a short piece of 1 inch aluminum square tube to the outside as a heat sink. I lapped it to the side and used heat sink compound and under the same mounting screw as the triac and it gets too hot to touch. I don't think the plate that the dimmer is made on would be near enough to deal with the heat over a full run, at least not at 220v.
I probably wont have a chance to try out the extra resistor that rad suggested for a while. I have a good supply built up now that should last me a while.
Even as sensitive as it seems to be it is really nice compared to propane. Now to work on quick disconnects for my cooling lines and a stand for my keg so I can ditch the bricks.

[Pamulli]

Glad to hear you got it going. How are you dealing with the heat of the triac?
I made another run this weekend and am concerned with the heat buildup in my aluminum outdoor 2gang box. I put a short piece of 1 inch aluminum square tube to the outside as a heat sink. I lapped it to the side and used heat sink compound and under the same mounting screw as the triac and it gets too hot to touch. I don't think the plate that the dimmer is made on would be near enough to deal with the heat over a full run, at least not at 220v.
I probably wont have a chance to try out the extra resistor that rad suggested for a while. I have a good supply built up now that should last me a while.
Even as sensitive as it seems to be it is really nice compared to propane. Now to work on quick disconnects for my cooling lines and a stand for my keg so I can ditch the bricks.

I mounted the triac to a heatsink and I'm hoping that is enough. It's the size of single gang box. It did seem to get fairly warm during the testing, but I'm not sure there is anything else I could do other than install a fan in the switch.

[Pamulli]

OK so as promised here is the documentation for my 240V switch. Thanks to Rad's suggestion, mine turned out to be different than anything else I've seen on here since I used an unmodified off the shelf dimmer rather than adding a new Pot and capacitor. I have no idea if this is going to have a shortened life span, I just know that it works at the moment with a 4500W element. I also haven't done a complete run with it yet, just heated water. I'm posting it now because I've gotten some IM's asking for more info. If I later see issues with this setup I'll come back and post.

Parts List
Dimmer: Lutron D-600PH-DK (It's important that you use this dimmer or one with similar circuitry. I got mine at Ace for less than $12)
Triac: LittleFuse Q6040J7 - Mouser PN 576-Q6040J7
Wirewound Resistor: Arcol HS25 75R 1% - Mouser PN 284-HS25-75F

Underside of Lutron Dimmer

Parts in place without connections

Resistor and Triac are mounted to an aluminum heatsinc

Final Switch without cover plate

Switch Diagram

I tried to make the diagram as simple as possible for those of us who find electrical diagrams confusing.
One thing to note is that all of the ground wires are connected, but not shown in the diagram.

Hopefully this will be of use to someone.

[Pamulli]

Here are a couple of low quality pictures showing the final product.

Element attached to keg

The keg is grounded back to the main electrical, you just can't see it in this picture.

[rad14701]

That's some helpful documentation, Pamulli...

If the controller handles water without any problems then I would expect it to work fine with a wash...

That beefy dual time constant dimmer should hold up well...

Keep us posted on spirit run performance...

[Pamulli]

Yea the one thing I don't yet know is sensitivity and how easy it is to control. I know that all the way up will bring the water to a hard boil and all the way down will drop it below boiling so I would expect the control to be sufficient with a wash. it may be a little while before I do real run, but I'll post the results when I finally get to it.

Thanks,

[Pamulli]

I have a question about the heat this switch is producing.

Right now I have both the Resistor and Triac mounted to the heatsink, which is getting pretty hot and the Resistor is rated up to 200C while the Triac is only rated at 125C. Does the Triac need to be on the heatsink or should I move it off so that it isn't getting heated up by the Resistor? The heatsink is pretty big so the only way I know to cool it better would be to install a fan, but that is getting more complicated than I'd like.

Thanks,

[Bob421]

I think your heatsink needs to be outside the box. With the fins oriented up and down to get some airflow.
In mine the resistor doesn't seem to get that hot ( I am using the same one as you) so I don't think you would really need to move it off the heatsink especially since it can handle higher heat than the triac.

[Pamulli]

I wasn't sure if the heat was coming from the Triac or the resistor?
I have the fins oriented up and down and I have holes in two sides of the box for airflow....you don't think that is sufficient?

[Bob421]

Maybe it's good enough, that is a pretty big heatsink.
By up and down I mean you would have the ends of the fins pointing to the right or left so that rising heat would make the air flow through it.
At least the way it looks in the pictures the fins are on the bottom of the box pointing down.

[Pamulli]

I guess I'll keep an eye on the temp and if it seems like it's getting too hot I'll try moving the heatsink outside the box and changing the orientation.

Thanks,

[rad14701]

Pamulli, do you have any vent holes to allow the heat out and cooler air in...??? The triac is probably producing the most heat and will require some air flow to stay below critical temperatures...

[Pamulli]

Yes I have vent holes on two sides.

[HookLine]

Yes I have vent holes on two sides.

Add some vent holes on the top, as many as on both sides total. Get the air flowing in the sides (or bottom), and out the top.

[Bob421]

Anyone know why I couldn't build my own hotplate from a 240v stove coil using this circuit to drive it.
A quick search turned up a 2600 watt one.

[rad14701]

Anyone know why I couldn't build my own hotplate from a 240v stove coil using this circuit to drive it.
A quick search turned up a 2600 watt one.

You can... They just aren't quite as efficient as an internal element, but they will work just like any other hot plate - without the cycling...

[Bob421]

Cool, I am thinking about making beer and I want to be able to boil stuff in a pot in the shop.
My stand is getting more complicated all the time.

[AJ Cotton]

I'm still working on Pint's 120v design, finally gearing up to build the thing so now I just need the dimmer and.. a soldering iron

Can anybody recommend an appropriate iron for this project? As a rank amateur when it comes to soldering, the wattages, not to mention that whole "big wires, little components" thing has me stumped.

As for soldering the new components in, did you guys just twist your stripped wires into a braid and solder them to the appropriate terminals? It seems like that connection would be pretty weak, even though nobody's going to be tugging on these hopefully.

For example I had considered trying to thread some portion of the stripped wire through the 'eyelets' on my resistor before soldering, but that got bulky and impractical on a test fit. Is there a better way to do things I'm not thinking of?

Thanks for all your help.

[snideman]

Can anybody recommend an appropriate iron for this project?

Any soldering iron that will reach the melting point of the type of solder you are using will do.

the wattages, not to mention that whole "big wires, little components" thing has me stumped.

Be sure to rate your wires to the power requirements of the heating element you are using.

As for soldering the new components in, did you guys just twist your stripped wires into a braid and solder them to the appropriate terminals? It seems like that connection would be pretty weak, even though nobody's going to be tugging on these hopefully.

A proper soldering technique will produce a connection at least as strong or stronger that the materials you are joining, if they pull apart it was a cold solder or no flux was used.

For example I had considered trying to thread some portion of the stripped wire through the 'eyelets' on my resistor before soldering, but that got bulky and impractical on a test fit. Is there a better way to do things I'm not thinking of?

Refer to above, I have seen people split the braided wire in two, thread one portion through the eyelet and twist the pair together, then solder, however, this is complete overkill and makes for a bulky installation.
Thanks for all your help.[/quote]

[rad14701]

AJ Cotton, the cheapest 40W soldering pencil will do the trick... They are available for under $10 USD around here and I can usually find them as discount stores for under $5 USD... No need for an expensive solder station... Once the controller is completed you can use it to regulate the solder pencil, making it your own solder station... Yet another use and justification for your controller...

[Bob421]

A 25 watt one is NOT up tot he task. I couldn't find my 40 watt one and had to use a little butane torch to heat the tip extra hot to get that big wire whetted with solder. Hey sometimes you gotta make do with what you have especially late at night.

[AJ Cotton]

sniderman: I was thinking about a short length of 14/3 for the wiring of this controller since I've been reading 14/3 has a max rating of 15amps/120v up to a length of 50ft, that sound right for a 1500w/120v element?

rad14701: That's great news! I was just looking at the 40w pencils yesterday when a friend tried to convince me I needed a Hakko station!

Bob421: Hey as long as it works.

Thanks!

[snideman]

sniderman: I was thinking about a short length of 14/3 for the wiring of this controller since I've been reading 14/3 has a max rating of 15amps/120v up to a length of 50ft, that sound right for a 1500w/120v element?

You will do just fine with that, the most I draw on 220vAc on my 2500 watt element is 10.5 amps per leg. I'm sure others will chime in on ohm's law and p=ixe and such so stay tuned.

[Dnderhead]

be safe and go with 12/3 not all that much difference in price. most handy-dandy hardware stores carry it by the foot. or you can salvage a appliance cord molded plug and all.

[AJ Cotton]

Dnderhead: Point taken, I'll keep my eyes peeled for 12/3 next trip to the hardware store.