Correct SSR for my setup? - Home Brew Forums

Register Now!
Home Brew Forums > Home Brewing Beer > Electric Brewing > Correct SSR for my setup?

Reply
 
Thread Tools
Old 09-30-2012, 04:33 PM   #1
JBiermann
Recipes 
 
Jul 2012
Portland, Maine
Posts: 23


So I'm muddling my way through my first RIMs build (I'm just using a closed RIM's circuit on my mash tun, the rest of the process will be using conventional propane burners) and I'm trying to find the right SSR and heatsink. My element is a camco 4500W 240V and my temp control is a MYPIN TA4. The SSR's Im looking at sometimes dont go as high as 240V (an issue?) And why would the SSR convert the AC signal to DC? Is that necessary for the element? If someone could just tell me what to get I'd be very appreciative.

Cheers,

Biermann

 
Reply With Quote
Old 09-30-2012, 04:48 PM   #2
nitrousjunkie
Recipes 
 
Sep 2007
Honolulu HI/ Hickam AFB, Hawaii
Posts: 205
Liked 4 Times on 1 Posts


The SSR will control one leg of your 240 line, so it will only see 120 going through it. It does not convert ac to dc power. Your controller sends a dc signal to the ssr. Think of the ssr as a very high speed relay.

 
Reply With Quote
Old 09-30-2012, 05:00 PM   #3
JBiermann
Recipes 
 
Jul 2012
Portland, Maine
Posts: 23

Alright, so let me try and trace this as simply as possible. Household current -> temp controller -> SSR -> heating element. Am I missing a step here? Should there be "contactors" in the loop somewhere and what do they do? I feel like the concept is so simple but since starting this project im regretting that I didnt major in electrical engineering. And any SSR and heatsink in ebay or the equivilant will suffice?

 
Reply With Quote
Old 09-30-2012, 06:23 PM   #4
nitrousjunkie
Recipes 
 
Sep 2007
Honolulu HI/ Hickam AFB, Hawaii
Posts: 205
Liked 4 Times on 1 Posts


Main power in, that supplies power for your temp controller(pid). The controller sends a signal to the ssr ( two wires from controller to ssr). Then one leg of your 240 in goes to the ssr in, ssr out will go to element power out. You can put a contacter between the ssr and element power out and have it on a switch. Look at some of PJ's wiring diagrams. That should help explain.

 
Reply With Quote
Old 10-01-2012, 02:06 AM   #5
JBiermann
Recipes 
 
Jul 2012
Portland, Maine
Posts: 23

cheers

 
Reply With Quote
Old 10-01-2012, 04:16 AM   #6
thargrav
Registered User
Recipes 
 
Dec 2009
Huntsville, Alabama
Posts: 821
Liked 38 Times on 35 Posts


Quote:
Originally Posted by nitrousjunkie View Post
The SSR will control one leg of your 240 line, so it will only see 120 going through it. It does not convert ac to dc power. Your controller sends a dc signal to the ssr. Think of the ssr as a very high speed relay.
Not true - the SSR needs to be rated for at least 240 VAC. This is because even if you use two, one to control each leg, slight timing differences could cause one to "see" 240 VAC. And 240 VAC for even a very short time will blow out a 120 VAC rated SSR.

Also, for 4500 Watts @ 240 VAC you need a SSR rated for at least 20 Amps (4500 / 240 = 18.75). A 40 Amp SSR is over kill. a 25 or 30 Amp gives you some safety margin.

 
Reply With Quote
Old 10-02-2012, 06:02 PM   #7
fork
Recipes 
 
Mar 2008
Posts: 120
Liked 8 Times on 7 Posts


I concur, in a 240 volt circuit both wires are hot and carry the full voltage. You need a 240 v ssr.

 
Reply With Quote
Old 10-02-2012, 07:28 PM   #8
thargrav
Registered User
Recipes 
 
Dec 2009
Huntsville, Alabama
Posts: 821
Liked 38 Times on 35 Posts


Also, I see some designs with 2 SSRs, one for each leg. I don't understand why since you are switching current & not voltage and you only need one.

I'm sure someone will chime in with "I use two SSRs to switch off both legs for safety". I suggest you measure the voltage across both sides with the SSRs off & the element disconnected - you will measure 240 VAC!

 
Reply With Quote
Old 10-02-2012, 07:35 PM   #9
fork
Recipes 
 
Mar 2008
Posts: 120
Liked 8 Times on 7 Posts


Using two ssrs would be safer, without switching off both lines there is still hit voltage at the wire. You can accomplish this with a switch rated for 240 on the second leg. I think you measure voktage at ssrs when they are off because of leakage. I'm not sure but i think you can measure voltage but no appreciabke current will flow.

 
Reply With Quote
Old 10-02-2012, 07:42 PM   #10
thargrav
Registered User
Recipes 
 
Dec 2009
Huntsville, Alabama
Posts: 821
Liked 38 Times on 35 Posts


Relying on the SSRs for safety is dangerous. Using a disconnect or some type of switch ahead of the SSRs is the only way to guarantee safety.

 
Reply With Quote


Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Are These The Correct Items For My Heating Element LiquidFlame Electric Brewing 6 09-27-2012 01:30 AM
Wiring the Lights, is my simple diagram correct? MDF99 Electric Brewing 2 09-16-2012 01:55 PM
Correct power requirements for step mashing Bensiff Electric Brewing 17 12-10-2011 04:22 PM
Correct power requirements to boil BadWolfBrewing Electric Brewing 17 11-04-2011 07:17 PM
Economical and correct receptacles-plugs for 240V 50A clearwaterbrewer Electric Brewing 33 03-03-2011 02:55 PM


Forum Jump