Pwm

[Toejam792]

Can I use a cheap ebay PWM with a solid state relay for boil control without modification. I read about how hz matters, but most of them just tell you about the volts and amps. Also were do people get the cool large dials from. The ones I've seen have wimpy small dials, it's not the same when your cranking it up to 11.

 

[Riot]

Do a Google search that looks something like site:homebrewtalk.com pwm how to. There is an old thread that discusses this, basically you just replace the capacitor on the eBay pwm controller to get the frequency lower, multiple people on this site have gotten it to work successfully

 

[Brumateur]

could you provide a link(s) to a "cheap ebay PWM"?

 

[Riot]

This is the thread I was talking about. https://www.homebrewtalk.com/showthread.php?t=221301

And this is an inexpensive pwm module. http://m.ebay.com/itm/10A-6V-12-24V...ol-Switch-Controller-/371384244118?nav=SEARCH

 

[Toejam792]

They talk about switching capacitors in that thread. I'm all for it, just need to know what one to replace and what to replace it with. The pwm I saw on ebay is: http://www.ebay.com/itm/Quality-Mot...604118?hash=item234fdaf196:g:KRMAAOSw2XFUmUz1

I was wondering if I could just hook it up to ssr without modification.

 

[Brumateur]

All that "motor control" PWM work on hi frequency and can not be used for boil control without modification.

 

[augiedoggy]

@Toejam792 Why not just go with something like this? I bought one and they are very good quality... the 40A version is $2 more... you can check out the one I bought in person if you want although the panel isnt done since its one I'm building to sell... your only about 10 mins or so away from me.
http://www.ebay.com/itm/1pc-KYOTTO-...17c5738&pid=100005&rk=1&rkt=6&sd=140553987088

 

[Toejam792]

Augie: I don't get how that gets a completed circuit and I already ordered a 40a ssr. That looks like it is a dimmer switch. Does it only supply a percentage of the current or is it the amount of time on and off like a pwm?

Bru: I'm willing to modify and have sodering iron. If you could show me what pwm and capacitor will work. I'm sure I can put them together.

 

[Brumateur]

Augie: I don't get how that gets a completed circuit and I already ordered a 40a ssr. That looks like it is a dimmer switch. Does it only supply a percentage of the current or is it the amount of time on and off like a pwm?

It's sort of PWM for AC current - phase angle control.
https://en.wikipedia.org/wiki/Phase-fired_controllers
Diagram is very simple

 

[Toejam792]

So the ssr part supplies power to the potentiometer? Thats the part i didn't get. Otherwise that seams perfect

 

[augiedoggy]

So the ssr part supplies power to the potentiometer? Thats the part i didn't get. Otherwise that seams perfect

its not a regular SSR... its an SSVR solid state variable relay which is different. Just an FYI so you dont attempt to hook a potentiometer to your ssr it wont work.

 

[Toejam792]

I ordered the 40a version thanks a lot guys. Now I just need to run the line to my garage. I haven't started researching yet but do you know if I can run a 4500w element at 240 and a 1500w at 120 on a 30a circuit.

 

[Brumateur]

I haven't started researching yet but do you know if I can run a 4500w element at 240 and a 1500w at 120 on a 30a circuit.

Not at the same time from the same 30 Amp circuit. 4500W element needs around 19Amp and 1500Watt/120V element requires 12.5 Amp. So you need more than 30Amp to run both.

It's better to find 1500 Watt /240V element. This way you'll need only 25Amp to run both simultaneously.

 

[augiedoggy]

I ordered the 40a version thanks a lot guys. Now I just need to run the line to my garage. I haven't started researching yet but do you know if I can run a 4500w element at 240 and a 1500w at 120 on a 30a circuit.

You can however run a 4500w element with an 1800w 240v element along with the rest of your panel at the same time... (I do )
I have 3 4500w elements and the most any of them draw is 18.4 amps. they vary but are always slightly under the rated power.. I use 3 Dc powered pumps so they dont even draw an amp together... The rest of my panel draws under an amp..

check into the "cartridge heater"s and you will find a lot of 240v lower power options. I use them in rims tube builds. like the one in my build thread below.

 

[mabrungard]

The Auber Digital SSR Power Regulator is a pretty sweet unit for controlling the boil. It even has a nice LED readout on the setting. I have one and recommend it. $34

 

[Toejam792]

I'm intrigued by the cartridge heater. Do you use a stainless compression fitting to make it watertight?

 

[UndeadFred]

I got into this a little late.. but those "SSVR"'s are just phase control dimmers (like a standard light dimmer, yes) with the ability to hook to a big heat sink, run at 220V (and at higher current due to the heatsinking and slighly better TRIACS internally). The Potentiometer is literally part of the phase control circuit*, so you could sort of say it's powered (ok, it is).. but it isn't isolated like a standard solid state relay which uses optical coupling.. so bear that in mind. It is high impedance at 470K ohms so it's mostly safe anyway...

I am building up a box for boil, and a separate box for mash with a proper PID and SSR. I had all the parts for the second case already.. putting it into two boxes means I can in theory use both at once in two different vessels.. so it wasn't that much more expensive to go that way. It is why many people buy the Auber PID unit that emulates a proper PWM by having the software modified to pulse the element on and off (over a matter of seconds) with a standard SSR in "PWM" mode or "boil" mode.

*The phase control switches the TRIACs on for a portion of each half of the AC cycle.. the amount is controlled by the potentiometer....
Fred

 

[Toejam792]

I've put a parts list together for the rims tube in ebay. The element I was looking at was this: http://www.ebay.com/itm/390993852374

and compression fitting : http://www.ebay.com/itm/221923533097

It looks to me like that element is square, I'm going to contact the seller and ask but those should work together if its round right?