Need some advice on this electrical diagram

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

NTabb

Well-Known Member
Joined
Dec 21, 2009
Messages
85
Reaction score
5
Location
Shepherdtown
Guys,

Need some input if this diagram looks correct. I only want to run one element at a time and be able to switch between them with a 3 position switch. The system will be controlled with a BCS460 that I've been using for about a year now. The part I'm getting confused on is the mechanical relays and the 3 position switch. Thanks for any input!

Presentation3.jpg
 
The only change I might make is to wire the SSRs behind the relays, that way the SSRs are also cold when the switch is off for that leg.

Functionally, it doesn't make a difference. I just would rather not have it actually switching voltage when that leg isn't turned on.

-Joe
 
Also out of curiosity, why are you using SSRs for the pumps? Are you controlling them with a BCS or something?

Here is 1/2 of my system's wiring just to illustrate what I was saying about the SSRs behind the relay (which I called a contactor here).

nostalgia-wiring-1.jpg


-Joe
 
The pumps will be controlled by the BCS. I'll try to draw up another diagram with your suggestion.
 
I would also suggest to put the SSRs behind the relays. Any reason why you're running a second breaker for your 110V stuff as opposed to just taking one of your legs from the 220V breaker and wiring that through to your pumps?

I'm doing something similar to you. Here's my schematic:

5350853362_2f553a29a1_b.jpg
 
Alright so I think I'm confusing myself here. So when you guys are talking about putting the SSR's behind the relays, are you talking about moving leg 2 from the 240 and moving it to the SSR and then to the mechanical relay?
 
I just realized my schematic doesn't show the contactor where nostalgia and I are suggesting.

I'll redraw my schematic in the morning to show it the right way.
 
Mine does show it though - imagine my contactor is your relay. See how the black lead going to the SSR is switched by the relay? That means when your 3-way switch shuts off the contactor, there will be no power to the SSR.

-Joe
 
I think I may understand. Basically i need to go from the breaker to the mechanical relay, then to the SSR, then to the element
 
I'm trying to find the right 3 position switch to order and all I keep coming across is the 110-600VAC 10A Maximum. Will this switch work or do I need one that will handle more amps?
 
10A will be more than enough. You probably need less than 1A to drive the coils. Check the ratings on the relays.

-Joe
 
That makes a little more sense. I can definitley wait a couple weeks and would be more than happy to pay shipping plus whatever the switch cost.

I appreciate all the advice from you guys. Thought I would post a pic of what your helping me on.

DSC01332rev.jpg
 
Nice!!!! I like the hop grenade detail (as well as all that shiny hardware).

Edit: I'll keep you posted on that switch.
 
I used to have my contactors upstream from my SSRs (between line and SSR). I recently did some rewiring and changed the contactors to downstream of the SSRs (between SSR and load). Why do you think it makes a difference? Will they produce more heat? Premature SSR failure?
 
I think the idea is to minimize the current in the SSR. if it doesn't need to be there, and you can keep it out, why not?
 
Got me there. I'm not an electrical engineer. But in general, why energize a circuit if you don't need to.

edit: another thing to add. If an SSR fails (either due to too much load, age, etc.) switching the power off leading the the SSR can be accomplished via the contactor (or i guess ultimately pulling the plug, which wouldn't be ideal if you have other non-failed electronics running off the same power supply, like in the case of a control panel).
 
Yeah, I don't know for sure either, which is why I am asking the question. If the SSR fails, it really doesn't matter which side you have the contactor on because you can turn off the load (element) either way. Its not like you are going to replace the SSR without unplugging the control panel.
 
My thoughts were if there were a catastrophic failure that caused melting (i think it happened recently with someone on here). And yea, definitely no replacing the SSR without cutting all power.
 
So I think I would make a change after going live with this setup. Since I want to be able to automate the control of the elements(basically setting a temp in the HLT or Duty Cycle in the boil) I would throw in 2 more SSR's on Leg 2(red wire in the drawing)and use another output off the BCS. Without them I have to maunally turn the 3 way switch every time I want the element on or off. Just thought I would post this in case anyone else gives it a shot. Hopefully you guys can chime in if I'm incorrect about this.

Thanks
 
I spoke to an electrician at my work and he THINKS (not quite sure) that if the element has only 1 leg energized that it still won't work because it needs both legs. I was too paranoid to try it during my first batch. My assumption was if one of the 120V legs was energized then theres power going to the element. Can someone clarify this for me? My post before this one gives a little more detail.
 
You know, you CAN drive more than one SSR off of one output on the BCS, right? It might simplify your use of 2 SSRs to control the element.

Also, I'm pretty sure the electrician you spoke to is incorrect. People have been able to use 220V elements on 110V. If you search these boards you'll find it. I believe the output of the element becomes 1/4 of its rated value at proper voltage.

So if one leg is controlled via SSR and the other leg is wired to the element, it'll be outputting 1/4 power, because it is running on 110V.
 
I think NTabb is referring to the one vs two SSRs to control a 240 vac circuit. You only need one, especially if you have a hard shut off like your definite purpose contactor. If you cut off the juice to one limb of the 240 vac circuit, the there will be no output to the element. That said, many people using the BCS have an SSR on each limb of the 240 vac circuit. You can control both SSRs with one BCS output. If you don't have a hard shut off, then IMO, two SSRs are required.
 
After a little more research I went ahead and purchased 2 more SSR's. Sounds like the best and safest option. I don't like the idea of 1 leg still being hot when the BCS output is disabled.
 
I added a 30A GFCI breaker and it trips every time I turn the 3 position switch to allow current past the mechanical relays. I have the SSR's off so current is not making it to the elements (Also I added two more SSR's not shown in the diagram. L2 off of the 30A circuit is going to a SSR just like L1). I think I see my problem below. I have the neutral going to the other side of the coil on the DPDT relay. Is this correct? If not, what cable should be going there? Thanks for the help.

Revised-1.jpg
 
Back
Top