Finished electric rig, bye bye propane!

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Goocher

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Just wanted to share my victory with people that actually care. SWMBO could care less...

This is my new HERMS 2 vessel single element rig. I plan on expanding to three vessels and adding an additional element somewhere down the road. The keggle on the left will double as HLT and BK. Since I'm batch sparging, I'll just drain first runnings into a bucket. I'm using a Auber 2352 PID, Camco 5500W element, 40A SSR, 25' 3/8 copper HERMS coil, stainless valves, camlock quick disconnects, Bobby M's sightglass/thermometer, DIY coutnerflow chiller and DIY hop stoppers (for both BK and MLT).

Ready for a wet test this weekend!

20120321_210219.jpg

20120321_210250.jpg

20120321_210257.jpg
 

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oakbarn

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I thought that we might change to semi electric. I like the quick heat of propane but would like the control you have with the element. We use a HERMS (Chincilla) and control the temp of the Hot Water Bath with propane. We would raise to temp using prpopane and then control using a PID and an element. We have a Stout HLT with built in HERMS coil ordered. I will heat with propane but then add a RIMS tube with a PID to control the bath temperature. I am hoping for a BCS 462 on my Christmas list!
 

audger

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those open bus bars in the box are a little worrying.... those are OK to use for ground/neutral connections, but not for hot wires. be very careful around them. if that SSR heatsink falls off you are in for some excitement...
 
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Goocher

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They're held on by one of my best friends JB Weld... I scratched/scored both surfaces and prepped with rubbing alcohol before attaching them. Not worried though, strong as a rock.
 
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Goocher

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How are you moving the SSR heat out of the box?
The picture of the box was when it was about 90% complete, I have an exhaust fan now. Although, not sure that it's totally needed. I've heard mixed reviews...
 

bigljd

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I thought that we might change to semi electric. I like the quick heat of propane but would like the control you have with the element. We use a HERMS (Chincilla) and control the temp of the Hot Water Bath with propane. We would raise to temp using prpopane and then control using a PID and an element. We have a Stout HLT with built in HERMS coil ordered. I will heat with propane but then add a RIMS tube with a PID to control the bath temperature. I am hoping for a BCS 462 on my Christmas list!
Quick heat of propane? An electric element(s) running on 240v is going to heat water/wort quicker than propane, unless you are using a space shuttle booster rocket as your burner. Electric is much more efficient too.
 

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Can you show a pic of the inside of the completed box. unless im missing it, i dont see the dpdt 30amp relay in there
 
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Goocher

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Can you show a pic of the inside of the completed box. unless im missing it, i dont see the dpdt 30amp relay in there
I'm not using a DPDT relay. I cheated and used one of PJ's diagrams. I am using a 25A DPDT (on-off-on) switch. On a diagram it would be in between the SSR and the element. I plan on adding a dedicated BK with another 5500w element. When I upgrade I'll use this switch to select which element is firing.
 

bagpiperjosh

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I'm not using a DPDT relay. I cheated and used one of PJ's diagrams. I am using a 25A DPDT (on-off-on) switch. On a diagram it would be in between the SSR and the element. I plan on adding a dedicated BK with another 5500w element. When I upgrade I'll use this switch to select which element is firing.[/QUOTE

i thought you pretty much needed to have some dpdt relays. if not then why does anyone use them? they are expensive as heck!

do you have a link to the switch you bought?
 
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Goocher

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I'm not using a DPDT relay. I cheated and used one of PJ's diagrams. I am using a 25A DPDT (on-off-on) switch. On a diagram it would be in between the SSR and the element. I plan on adding a dedicated BK with another 5500w element. When I upgrade I'll use this switch to select which element is firing.[/QUOTE

i thought you pretty much needed to have some dpdt relays. if not then why does anyone use them? they are expensive as heck!

do you have a link to the switch you bought?
Here's the PJ diagram that I based my build on. The switch is from Grainger

I also added an E Stop to trip the GFCI, per PJ's instructions (though it's not shown on the diagram). Two 1K resistors in a series to leak a small amount of current to ground. Works like a charm.

Single element electric diagram.jpg
 

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it says that the switch is rated for 15 amps @240 volts.... so that will be ok for that? seems like its not enough

EDIT: I think i answered my own question... because you are only hooking up one leg of the 220 it doesn't put too much power to it.
I had the same question. I trusted PJ's diagram but verified with a couple technicians in my office. They agreed.

Any experts want to chime in and share a technically sound answer?
 
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Goocher

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Switch is OK. It's only seeing 1 leg (i.e., 120V) and very little current (Pump ~ 2A, PID power ~ 0A).
The switch is used for power to the element. So, actually it's seeing 22.9A [5500 (W) / 240 (V) = 22.9 (A)] The question is... is the rating of the switch for each leg or is it for combined voltage?

Here's the switch in question...


Single element electric diagram switch in question.jpg
 
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The switch is used for power to the element. So, actually it's seeing 22.9A [5500 (W) / 240 (V) = 22.9 (A)] The question is... is the rating of the switch for each leg or is it for combined voltage?

Here's the switch in question...


View attachment 53795
woops. I thought it was the switches below.

According the specs, the switch is not rated for this app. I don't understand though why it has a lower current rating for 240VAC.

I looked at the spec. The switch has a dielectric rating which determines the highest voltage allowed. This switch will see 240VAC between the the poles and 120V from each pole to ground (i.e., the operator). It's rated for that, so that's ok.

The switch also has contact resistance that will cause it to heat when current is run through it. This heating is only dependant on the current (not voltage). The switch is rated for 25A (at 120V though), so I guess that is OK too.

Technically I think the switch will work fine. Still, I'd just put one in there that has the proper ratings - this one doesn't. There must be some reason NKK derates the switches under 240V.
 

CidahMastah

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The picture of the box was when it was about 90% complete, I have an exhaust fan now. Although, not sure that it's totally needed. I've heard mixed reviews...
I think the exhaust fan is a great idea and needed for your application.

Not sure the melting point of those nema boxes but I had a similar heat sink on my first control panel and in free open air (lid of the project box and metal to conduct away heat) it was 190F. I am sure closed in an airtight box like yours is it would be hotter than 190F over the course of a brew session and potentially exceed the heat rating for that box.

However I have no idea what the operating range is for that plastic. i.e. better safe than sorry with that fan.
 

CidahMastah

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Looks like I am finding not to exceed 176F for the carflex watertight conduit. I think the conduit is made from the same material as the junction boxes from carlon. Running your rig without a fan is sounds risky.
 
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woops. I thought it was the switches below.

According the specs, the switch is not rated for this app. I don't understand though why it has a lower current rating for 240VAC.

I looked at the spec. The switch has a dielectric rating which determines the highest voltage allowed. This switch will see 240VAC between the the poles and 120V from each pole to ground (i.e., the operator). It's rated for that, so that's ok.

The switch also has contact resistance that will cause it to heat when current is run through it. This heating is only dependant on the current (not voltage). The switch is rated for 25A (at 120V though), so I guess that is OK too.

Technically I think the switch will work fine. Still, I'd just put one in there that has the proper ratings - this one doesn't.
Dang. PJ's wrong then? I thought he was a guru for budget electric. For some reason, I can't scale the image up. This was the exact switch that he spec'd in his diagram (part # is listed on the bottom).
 
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Dang. PJ's wrong then? I thought he was a guru for budget electric. For some reason, I can't scale the image up. This was the exact switch that he spec'd in his diagram (part # is listed on the bottom).
I don't know, maybe he's right; I guess he should come in here and explain. It's possible that the "250V" rating for that switch refers to that voltage from a single leg, for example 220VAC in Europe. Not really sure here.
 

aubiecat

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Good work Goocher. That plastic junction box is the way to go. plenty of room room for everything.
 

lschiavo

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When a switch is opened the resistance essentially changes from 0 to infinite. If you consider the switch a resistor in a 240V series circuit with the element there is an instant where the element resistance is negligible compared to the switch and you will see 240V across the switch contacts. IMO, the 240V current rating should be used.
 

bagpiperjosh

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When a switch is opened the resistance essentially changes from 0 to infinite. If you consider the switch a resistor in a 240V series circuit with the element there is an instant where the element resistance is negligible compared to the switch and you will see 240V across the switch contacts. IMO, the 240V current rating should be used.
so should i buy that switch for my setup or not?!lol
its way cheaper than 2 COILS thats for sure.
 

lschiavo

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bagpiperjosh

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If your element will draw more than 15A, I don't think the switch is rated for it.

Where have you looked for contactors? They look to be about $12/ea. here:

http://www.elecdirect.com/catalog/75abf43b-6115-4950-9e22-afc5ab4c82dd.aspx
I'm going by the links on theelectricbrewery.com they reccomend this

http://www.ebay.com/itm/400020892007?ssPageName=STRK:MEBOFFX:IT&_trksid=p3984.m1427.l2649

edit: im assuming this would be a good match?
https://www.elecdirect.com/product.aspx?id=2873
 

lschiavo

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bagpiperjosh

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Ahh, I see. That is a different animal. It is essentially combining two contactors in one unit although it does't appear to have an off position? I'd use it before the switch. If you are only controlling one element DPDT is not necessary.
well id like to do it how they have it. have 2 of those and a open-closed-open switch controlling the heating elements for the BL and HLT. so would 2 of those work for that?
 

lschiavo

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well id like to do it how they have it. have 2 of those and a open-closed-open switch controlling the heating elements for the BL and HLT. so would 2 of those work for that?
You are referring to the contactor I linked? If so, yes. One contactor for each element and a SPDT selector switch with OFF position to power the coils will work fine.
 

bagpiperjosh

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You are referring to the contactor I linked? If so, yes. One contactor for each element and a SPDT selector switch to power the coils will work fine.
well.... its the one i linked from the same website.. if so ill order a few of those soon
 

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The switch is used for power to the element. So, actually it's seeing 22.9A [5500 (W) / 240 (V) = 22.9 (A)] The question is... is the rating of the switch for each leg or is it for combined voltage?

Here's the switch in question...


View attachment 53795
I'm not an electrical engineer, just a lowly physicist/chemist, but there's a lot of bad advice being thrown around in this thread. I'm no safety nazi either, but you really need to change your design.

Apply nodal analysis to the nearest junction before the switch-element loop. You will see that the switch as a whole will actually see 45.8A. This follows from Kirchhoff's circuit laws. Each leg will have to carry the full loop current, and since there's two legs you get a big number. That's semantics, though.

What really does matter is not current or voltage, but the amount of power dissipation that the contacts on the switch can handle. When the switch is in the closed state it has some small internal resistance, much like wiring. This resistance causes heating based on power (energy per unit time) pushed through it. Depending on the design and materials there is a certain amount of heat (energy) that can move out of the contacts in a given amount of time (flux). If the amount of heat generated is too large the device melts, catches on fire, or otherwise breaks down. This is why it is generally considered bad, and usually against code, to run NMB inside conduit. The additional layers impede heat flow away from the wires. So that's why the switch is derated with respect to current at higher voltages, it generated too much heat.

That switch is not rated to handle the amount of power you are pushing through it. You should upgrade or use that switch to control a DPST contactor. When choosing a replacement switch or contactor for your application you need to find one that has a contact rating of at least 26 A at 240 V. Your current switch may be working fine for now because there's always a safety factor in those ratings, but it could also be on the verge of failure. If you want to keep it just add a 30 A 240V contactor with a 120 V coil. Disconnect all the legs from your switch and run them through the contactor. Run one hot leg from your hot buss through the switch, then to the contactor's coil. Run a neutral from your neutral bus to the other side of your contactor and you're set. It you want to you can also install a small inline fuse on the hot leg which will allow you to run smaller wire after the fuse.
 

bagpiperjosh

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I'm not an electrical engineer, just a lowly physicist/chemist, but there's a lot of bad advice being thrown around in this thread. I'm no safety nazi either, but you really need to change your design.

Apply nodal analysis to the nearest junction before the switch-element loop. You will see that the switch as a whole will actually see 45.8A. This follows from Kirchhoff's circuit laws. Each leg will have to carry the full loop current, and since there's two legs you get a big number. That's semantics, though.

What really does matter is not current or voltage, but the amount of power dissipation that the contacts on the switch can handle. When the switch is in the closed state it has some small internal resistance, much like wiring. This resistance causes heating based on power (energy per unit time) pushed through it. Depending on the design and materials there is a certain amount of heat (energy) that can move out of the contacts in a given amount of time (flux). If the amount of heat generated is too large the device melts, catches on fire, or otherwise breaks down. This is why it is generally considered bad, and usually against code, to run NMB inside conduit. The additional layers impede heat flow away from the wires. So that's why the switch is derated with respect to current at higher voltages, it generated too much heat.

That switch is not rated to handle the amount of power you are pushing through it. You should upgrade or use that switch to control a DPST contactor. When choosing a replacement switch or contactor for your application you need to find one that has a contact rating of at least 26 A at 240 V. Your current switch may be working fine for now because there's always a safety factor in those ratings, but it could also be on the verge of failure. If you want to keep it just add a 30 A 240V contactor with a 120 V coil. Disconnect all the legs from your switch and run them through the contactor. Run one hot leg from your hot buss through the switch, then to the contactor's coil. Run a neutral from your neutral bus to the other side of your contactor and you're set. It you want to you can also install a small inline fuse on the hot leg which will allow you to run smaller wire after the fuse.
So can i get a second OK for using these on camco 5500w elements? https://www.elecdirect.com/product.aspx?id=2873
 

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