New Giveaway - Wort Monster Conical Fermeneter!

Home Brew Forums > Home Brewing Beer > Electric Brewing > SSR, Contactor? both? help me K.I.S.S




Reply
 
LinkBack Thread Tools Display Modes
Old 06-02-2011, 01:07 PM   #11
Walker
I use secondaries. :p
Feedback Score: 0 reviews
 
Walker's Avatar
Recipes 
 
Join Date: Sep 2005
Location: Cary, NC
Posts: 11,238
Liked 70 Times on 62 Posts
Likes Given: 11

Default

Quote:
Originally Posted by warehousebrewery View Post
Id highly recommend using a contactor. They're fairly cheap on ebay. I got three for the price of one new one. Knowing that the element is off when I flip the switch is a good piece of mind for me. I'd also recommend using dual SSRs if you're using 240V. That's another topic of discussion.
Agreed. Some sort of manual cut-off switch is ideal. You can get a 2-pole switch at Home Depot or Lowe's that is capable of 30A and 240V, or you can use a contactor. It works out to about the same price.


__________________
Ground Fault Brewing Co.
Walker is online now
 
Reply With Quote Quick reply to this message
Old 02-11-2013, 07:31 PM   #12
chadillac7819
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2012
Location: Orlando, FL
Posts: 38
Liked 1 Times on 1 Posts
Likes Given: 2

Default

Quote:
Originally Posted by Walker View Post
Agreed. Some sort of manual cut-off switch is ideal. You can get a 2-pole switch at Home Depot or Lowe's that is capable of 30A and 240V, or you can use a contactor. It works out to about the same price.
Sorry to dig up an old thread but I'm trying to get some clarity on something...what is the benefit of having a contactor/coil and SSR tandem for a 240v connection vs. two SSRs? Is it merely cost or is there something else at play, like a 110v coil for lighting or other??? It seems to me two SSRs would be best but I am totally new to electric brewing.

BTW - if i do use two SSRs can I still put a three way ON/OFF/AUTO switch?


__________________
chadillac7819 is offline
 
Reply With Quote Quick reply to this message
Old 02-11-2013, 08:51 PM   #13
jeffmeh
Feedback Score: 0 reviews
 
jeffmeh's Avatar
Recipes 
 
Join Date: Feb 2009
Posts: 1,742
Liked 123 Times on 105 Posts
Likes Given: 15

Default

SSRs can fail closed (on), and can leak current. If you run both the output hot from the SSR and the other hot through a double pole single throw contactor, with the contactor coil controlled by a switch, then when you switch the element off, you know it is off.

You have no such assurance without the contactor, whether you have one or two SSRs. The second SSR is not necessary.

__________________
jeffmeh is offline
 
Reply With Quote Quick reply to this message
Old 02-11-2013, 09:54 PM   #14
processhead
Feedback Score: 0 reviews
 
processhead's Avatar
Recipes 
 
Join Date: Oct 2007
Location: Nebraska
Posts: 576
Liked 75 Times on 63 Posts
Likes Given: 3

Default

Speaking only from my own experience building and using my RIMS and building several electric meat smokers, I strongly favor SSR's as my primary power switching control.

A contactor/relay will certainly work in most instances, but keep in mind that a PID controller can cycle the power switching device at a fairly frequent rate in a heating system .

I feel more confident that a SSR will be more durable, with no moving parts, will stand up multiple on/off cycling better than a electromechanical contactor.


The price of SSRs can be very reasonable when purchased from a surplus supplier or off of Ebay.

I am sure an SSR can fail, although I have not seen it happen. Mechanical contactors can fail in a closed state too when tne contacts weld together.

__________________
processhead is offline
 
Reply With Quote Quick reply to this message
Old 02-11-2013, 11:07 PM   #15
ryane
Feedback Score: 0 reviews
Recipes 
 
Join Date: Nov 2008
Location: Phoenix, AZ
Posts: 779
Liked 5 Times on 5 Posts

Default

Quote:
Originally Posted by processhead View Post
Speaking only from my own experience building and using my RIMS and building several electric meat smokers, I strongly favor SSR's as my primary power switching control.

A contactor/relay will certainly work in most instances, but keep in mind that a PID controller can cycle the power switching device at a fairly frequent rate in a heating system .

I feel more confident that a SSR will be more durable, with no moving parts, will stand up multiple on/off cycling better than a electromechanical contactor.


The price of SSRs can be very reasonable when purchased from a surplus supplier or off of Ebay.

I am sure an SSR can fail, although I have not seen it happen. Mechanical contactors can fail in a closed state too when tne contacts weld together.

Your not using the contactor for pulsing the heating element, instead its used as a saftey switch so that you can cut power to the element should you want to. sort of an system on/off switch

without the contactor you are relying on the pid to cut power to the element, which isnt always quick or easy
ryane is offline
 
Reply With Quote Quick reply to this message
Old 02-11-2013, 11:14 PM   #16
processhead
Feedback Score: 0 reviews
 
processhead's Avatar
Recipes 
 
Join Date: Oct 2007
Location: Nebraska
Posts: 576
Liked 75 Times on 63 Posts
Likes Given: 3

Default

Thanks for setting me straight.

As a safety switch or main switch, a contactor would be a good choice.

__________________
processhead is offline
 
Reply With Quote Quick reply to this message
Old 02-11-2013, 11:25 PM   #17
chadillac7819
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2012
Location: Orlando, FL
Posts: 38
Liked 1 Times on 1 Posts
Likes Given: 2

Default

Quote:
Originally Posted by jeffmeh View Post
SSRs can fail closed (on), and can leak current. If you run both the output hot from the SSR and the other hot through a double pole single throw contactor, with the contactor coil controlled by a switch, then when you switch the element off, you know it is off.

You have no such assurance without the contactor, whether you have one or two SSRs. The second SSR is not necessary.
As a boiler plate statement...I am not married to my design and certainly don't mind the nominal investment of two contactors. I am just trying to understand this and get all perspectives since I am getting conflicting advice. Please don't mistake my curiosity with a need to defend my point of veiw!

That said, what if I have each of the two SSRs per element controlled by a 3 way switch before the relays with an ON/OFF/AUTO switch? Would the current leakage still be an issue? I would charge one side of a two pole double throw with a constant 5v and the other with my BCS462, which will always be on since it also does fermentation control. I also plan on putting a key lock in front of all the brewery operations shutting off all current when I am not brewing but not shut off the BCS. Will any of this help significantly? If not, please disabuse me of my ignorance!
__________________
chadillac7819 is offline
 
Reply With Quote Quick reply to this message
Old 02-12-2013, 01:19 AM   #18
jeffmeh
Feedback Score: 0 reviews
 
jeffmeh's Avatar
Recipes 
 
Join Date: Feb 2009
Posts: 1,742
Liked 123 Times on 105 Posts
Likes Given: 15

Lightbulb

Quote:
Originally Posted by chadillac7819 View Post
As a boiler plate statement...I am not married to my design and certainly don't mind the nominal investment of two contactors. I am just trying to understand this and get all perspectives since I am getting conflicting advice. Please don't mistake my curiosity with a need to defend my point of veiw!

That said, what if I have each of the two SSRs per element controlled by a 3 way switch before the relays with an ON/OFF/AUTO switch? Would the current leakage still be an issue? I would charge one side of a two pole double throw with a constant 5v and the other with my BCS462, which will always be on since it also does fermentation control. I also plan on putting a key lock in front of all the brewery operations shutting off all current when I am not brewing but not shut off the BCS. Will any of this help significantly? If not, please disabuse me of my ignorance!
I am not sure I am follwing you. Are you saying that you want to be able to force current to the element (ON), force to not pass current (OFF), or let the BCS control the current(AUTO)? If so, I'm not sure whether you would get real value from bypassing your controller and forcing the SSR to power the element at 100%. In any case, that is an additional requirement that would not be covered by the contactor configuration I described. That configuration either ensures that the element is off, or allows the element to be powered by the controller and SSR.

In your scenario, what is the DPDT device, a switch or a contactor?

The key safety feature is having a means to be sure that the element is off (even while you might want other components energized), because you cannot depend upon an SSR given the leakage and fail closed possibilities.
__________________
jeffmeh is offline
 
Reply With Quote Quick reply to this message
Old 02-12-2013, 12:03 PM   #19
chadillac7819
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2012
Location: Orlando, FL
Posts: 38
Liked 1 Times on 1 Posts
Likes Given: 2

Default

Quote:
Originally Posted by jeffmeh View Post
I am not sure I am follwing you. Are you saying that you want to be able to force current to the element (ON), force to not pass current (OFF), or let the BCS control the current(AUTO)? If so, I'm not sure whether you would get real value from bypassing your controller and forcing the SSR to power the element at 100%. In any case, that is an additional requirement that would not be covered by the contactor configuration I described. That configuration either ensures that the element is off, or allows the element to be powered by the controller and SSR.

In your scenario, what is the DPDT device, a switch or a contactor?

The key safety feature is having a means to be sure that the element is off (even while you might want other components energized), because you cannot depend upon an SSR given the leakage and fail closed possibilities.
The ON/OFF/AUTO is the path I have seen a lot of BCS users take on this forum (I think it is more relevent for the boil kettle and pumps than RIMS) in case the BCS or network crashes. It also helps with cleaning and tests. I was actually thinking of making the RIMS element an AUTO/OFF/ON (Momentary) switch so that I could pulse the element to keep the system at target mash temps should I need to give the system time to reboot.

Yes, I was thinking DPDT switches leading to the SSRs and SPST for all the pumps.

You are starting to convince me of the safety issues with the contactor coil and I can always save the extra two SSRs in case i need to switch one out on brew day (or expand). Any reccomendations on type fo contactor? Just a 30A 240V with a 110V coil for switches and lights?
__________________
chadillac7819 is offline
 
Reply With Quote Quick reply to this message
Old 02-13-2013, 05:57 AM   #20
mateomtb
Feedback Score: 1 reviews
Recipes 
 
Join Date: Jan 2011
Location: Pine, Co
Posts: 122
Liked 7 Times on 7 Posts
Likes Given: 7

Default

Check out some hot tub wiring and how they use a contactor and controls. Same idea, it's just basically a RIMS for people.

Yes use 3 way switches with BCS, it has been extremely handy in my system.

IMO dont' stress about the momentary switch. Once you're at temp you aren't going to loose temp that quickly if you loose heat control for a few moments. My BCS has lost connection and it takes less than a minute to restore, so far. Plus if it's a total meltdown and you are unable to restore bcs control at all, you'll have other issues to contend with to save your brew day like the boil. I know I can't run my element full throttle (manual) to boil, I run 5.5k at 55% for a 13 gallon boil. You would have to stand there and flip the switch on and off for an hour, it would be horrible.



__________________
mateomtb is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Looking for a 2 pole Contactor, 30A, 120V Coil that is Din rail mountable Windsors Electric Brewing 21 01-02-2012 05:39 AM
Contactor question GRHunter Electric Brewing 3 05-25-2011 11:32 AM
Contactor load HHP Electric Brewing 3 05-03-2011 01:13 AM
Mercury contactor vs. SSR burglar Electric Brewing 8 01-26-2011 01:48 AM