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-   -   Switching bt 2 5500w elements, 30amp circuit (http://www.homebrewtalk.com/f170/switching-bt-2-5500w-elements-30amp-circuit-373413/)

biertourist 12-11-2012 03:36 AM

Switching bt 2 5500w elements, 30amp circuit
 
What are the design options for someone who wants a 5500watt element in their HLT and a separate 5500w element in their Kettle but only has 30 amps of head room?

I've seen:
  • Use a 30amp 2 leg mechanical switch (don't like this option, too much personally)
  • The EBrewSupply 30 amp 2 element PID kit solution (3 way switch, 2 SSRs, 2 contactors)
  • Setup control panel as if you have a single element and just physically unplug the HLT and plug in the Kettle (I'd prefer to have both vessels permanently connected, but this is a really simple options)
  • Is there an option that uses a 3 way switch and a single SSR and contactor?

If you're supporting 2 elements with a single PID, won't switching the temperature sensor mess up the PID's calibration?


Thanks,
Adam

jakenbacon 12-11-2012 03:45 AM

whats the voltage?

jakenbacon 12-11-2012 03:47 AM

I mean max you can run, given voltage and wire gauge?

mdwilson 12-11-2012 04:19 AM

I don't see why you would need the contactor. You could use 2 SSRs and a two way switch to select one of the SSRs (on the low voltage side).

How are you driving the SSRs? The PIDs could get confused (integrator wind-up) if they are trying to drive a heating element that is turned off.

biertourist 12-11-2012 04:29 AM

Quote:

Originally Posted by mdwilson (Post 4670588)
I don't see why you would need the contactor. You could use 2 SSRs and a two way switch to select one of the SSRs (on the low voltage side).

?? Are contactors not the standard prescription when using SSRs? -The second bit of your recommend assumes that there's a brewery-style 3 way switch that could deal with 30 amps -I haven't found one, which is why I was thinking about going the switch + contactors route (plus this is how the EbrewSupply 30 amp 2 element kit does it).


Quote:

Originally Posted by mdwilson (Post 4670588)
How are you driving the SSRs? The PIDs could get confused (integrator wind-up) if they are trying to drive a heating element that is turned off.

Good call about the PIDs getting confused if they're trying to drive heating elements that are turned off... I didn't think about that at all. Does this really matter? -The pids don't just have an "off" button on them, do they? -I might have to include 2 more illuminated push button switches for the PIDs, huh?


Adam

biertourist 12-11-2012 04:34 AM

Quote:

Originally Posted by jakenbacon (Post 4670522)
I mean max you can run, given voltage and wire gauge?

The circuit going to my spa panel is a 4 wire 50 amp electric range outlet but the breaker itself is 40 amp, the GFI breaker in the spa panel is 50 amp; 6 awg wire to the spa breaker panel and 10 awg going to the control panel. All 10 awg wire in the control panel everywhere.

-If that's not the question that you're asking, please ask it again with a bit more detail.
Adam

runs4beer 12-11-2012 09:54 AM

Quote:

Originally Posted by biertourist (Post 4670605)
The second bit of your recommend assumes that there's a brewery-style 3 way switch that could deal with 30 amps -I haven't found one...
Adam

On the first page of this thread you will see a diagram that uses such a switch this is the same diagram that I'm currently using. I believe that the switches part number is at the bottom in the ledger of the diagram.
http://www.homebrewtalk.com/f170/opi...-plans-319852/

biertourist 12-11-2012 05:53 PM

Quote:

Originally Posted by runs4beer (Post 4670811)
On the first page of this thread you will see a diagram that uses such a switch this is the same diagram that I'm currently using. I believe that the switches part number is at the bottom in the ledger of the diagram.
http://www.homebrewtalk.com/f170/opi...-plans-319852/

This is the switch that's linked to in that diagram: http://www.grainger.com/Grainger/NKK...e-Switch-2TPF8

It's just a metal toggle switch and doesn't look like the rest of the brewery switches that so many of these systems are using. No offense, build whatever you want, but I just don't want everything else to use nice plastic push-button and turn-style switches and then to have a random metal toggle switch thrown in the mix.

This is a metal toggle switch that has 240v 30 amps running through it -something about touching a metal switch while my hands are wet while that switch has that kind of current running through it makes me unsettled.


The rest of the control panel has a common look and way of functioning and then there's just this big brute of a switch thrown in. I'd rather use the ebrewsupply solution with a 3 way 120v plastic switch controlling contactors. It's a personal preference and I understand that.


Adam

mdwilson 12-11-2012 05:56 PM

[QUOTE=biertourist;4670605]?? Are contactors not the standard prescription when using SSRs? -The second bit of your recommend assumes that there's a brewery-style 3 way switch that could deal with 30 amps -I haven't found one, which is why I was thinking about going the switch + contactors route (plus this is how the EbrewSupply 30 amp 2 element kit does it).


There seems to be a lot of interlocks on the E-brew schematic. I haven;t looked long enough to figure out their purpose. It looks like the contactors are used to completely shut off all voltage to the 240V sockets. I did not use contactors for my build and I assume that one side of the 240 volt socket is always hot.

Functionally you do not have to use a contractor with an SSR. You can wire one side of the 240V directly to the heating element and the other side of the 240v through the SSR and then to the heating element. Think of the SSR as a 40 amp switch. I was talking about using a low current switch between the low voltage side of the SSRs and the PIDs (the light blue wires in the Ebrew schematic). That way you use the SSRs to handle the high voltage and current, but you control things with low voltage low current switches. The low current switch (you could use a two position DPDT switch) would select which heating element is enabled.

runs4beer 12-11-2012 06:36 PM

Quote:

Originally Posted by biertourist (Post 4672182)
This is the switch that's linked to in that diagram: http://www.grainger.com/Grainger/NKK...e-Switch-2TPF8

It's just a metal toggle switch and doesn't look like the rest of the brewery switches that so many of these systems are using. No offense, build whatever you want, but I just don't want everything else to use nice plastic push-button and turn-style switches and then to have a random metal toggle switch thrown in the mix.

This is a metal toggle switch that has 240v 30 amps running through it -something about touching a metal switch while my hands are wet while that switch has that kind of current running through it makes me unsettled.


The rest of the control panel has a common look and way of functioning and then there's just this big brute of a switch thrown in. I'd rather use the ebrewsupply solution with a 3 way 120v plastic switch controlling contactors. It's a personal preference and I understand that.


Adam

I used this boot on my panel to address the functional concerns:
http://www.grainger.com/Grainger/NKK...tch-Boot-2TPX6

As far looks, my directive is always: functional before fashion.
After I decided to use this switch (I liked it's function) and boot I continued with that theme and picked all black components and used a black pelican case. I plan to use black out on all my lit buttons and lights so they appear black when not lit (like on custom car's brake light). I think it looks slick and I'm glad it doesn't look like all the other control panels out there.
I'm not to say you should do anything like that, more in that I understand your concerns on looks. Best of luck with your build.
-n


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