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Old 01-29-2013, 07:37 PM   #1
hot_carl
 
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I have a control box I'm building up now that is running on 120V, but I have built with the capability/plan to convert to 240V when I have the proper power feed. The control box only runs the HLT heater and the temp monitoring probes right now...wont control the boil keggle until I have 240 since I am doing 10 gal batches. At that point, I will run both the second porwer feed through the contactor and add the second SSR. I'm curious though if it would be possible to wire a control box up to be able to run 120 AND 240 elements. I'm now thinking of making a small 2.5 gal setup for test batches that I can run on a 120V outlet(so I can brew in the kitchen since I dont have a pretty basement brewery), but would like to use the same control panel if possible. I know the PID's would run on 120 in either scenario since it only getting one hot leg and a neutral. I'm no electrical engineer, but would this be as easy as having 2 different power inputs, the 120 wired directly to the hot bus in side then through the SSR, the 240 split, one leg to the hot buss one leg straight through the contactor to the element output(4 pole connector). That way the 240 should work as designed, and the 120V kettle/HLT will only use the grount, neutral and the one SSR switched hot lead from the output plug.

Again, this all seems kosher in my head, but I have no idea if this would work in reality.

 
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Old 01-29-2013, 07:50 PM   #2
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I should mention that all of the indicator lamps, switches and pumps are running off 120V, and the plan is to keep it that way. the only 240V power drain is the element.

 
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Old 01-31-2013, 01:39 AM   #3
Handsaw
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You want to be able to run with either 120 or 240 with the same control box, not both 120 and 240 at the same time?

 
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Old 01-31-2013, 04:19 AM   #4
hot_carl
 
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Correct, one or the other. It will do most of its duty on the 240v-15 gallon rig, but i would like to power a smaller 120v-2.5 gallon (likely BIAB with a single element) countertop kettle as well without building another panel. If i get a chance tomorrow, I'll post aome rudementary schematics and hopefully someone will point out if they are bogus or wont work.

 
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Old 01-31-2013, 12:23 PM   #5
BadNewsBrewery
 
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It could be done. The elements run on three wires. Hot A, Hot B, and ground when 240v and Hot, Neutral, and Ground when 120. You would then have two plugs - one that jumpered Hot B and Neutral so that you ran at 120 and another that had them separate for when you ran 240.

You would want to make extra sure you have a good wiring diagram that you mentally troubleshoot repeatedly before actually wiring it up, but it seems doable.
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Old 01-31-2013, 03:04 PM   #6
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Interesting thought problem.... I would think it would be easier, with fewer components, if you derive 120V from your 240V feed, when you run it. If you want to use the same PID and SSR whether in 120V or 240V mode, you would then always have H1 of your 240V feed running through the SSR. I don't know whether you can safely use H1 from a 240V feed and neutral from a separate 120V feed, but it makes me a bit nervous.

If you did this, and had the 240V feed, for each PID/SSR controlling a 120V or 240V element, you could use a 3-position selector switch, 120V-Off-240V. You would have two contactors, one for the 120V circuit (contactor1) and the other for the 240V circuit (contactor2). H1 runs through the SSR, then you split it and run it to both contactors. H2 runs to the contactor2 for the 240V circuit. After contactor1 H1 goes to a 120V receptacle, and neutral is tied in there also. After the contactor2, H1 and H2 run to a 240V receptacle. Of course, grounds are run to both receptacles. So now, selecting 120V closes contactor1 and opens contactor2, selecting 240V opens contactor1 and closes contacto2r, and selecting Off opens them both. I would also consider wiring a 120V led light in parallel with the 120V receptacle, and a 240V led light in parallel with the 240V receptacle, so you can get a visual confirmation when an element really has power.

Before you run your 240V circuit, you would have a 120V power inlet into your control panel, your 120V Hot input would go through an additional main power contactor, to your hot bus, then as described. You could defer (but leave room for) contactor2 for 240V, 240V receptacle, 240V led light, and the splitting of the Hot.

When you do install the 240V, you would swap out the 120V inlet for a 4-wire 240V inlet, then run Hot1 and Hot2 through your main power contactor, run Hot1 to your hot bus, and install the additional 240V componenents (contactor, receptcacle, led light, splitting of the Hot).

I think this would work, but I am not an electrician. Good luck with it.

 
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Old 01-31-2013, 03:21 PM   #7
msexton
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I was thinking about something similar. I think if you have your entire rig set up to work with 120 except use 10 gauge wire for the elements and any thing else that needs 240v. You would then only need 1 additional relay. When it is not energized the 120 neutral would be passed through to the elements. Have the coil energized by H2 and when energized, this would then open the 120 neutral and pass the H2 to the elements.

 
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Old 01-31-2013, 05:55 PM   #8
at3brew9
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Yes, you can do that--that's exactly the way my rig is set up. I can run both 120VAC heatsticks and the 240VAC elements in my HLT and BK. Make sure that when you pull in the wires for 240VAC that you have 4 wires. US household power systems have two hot legs that are 180 degrees apart, a neutral leg, and a ground leg. For 120VAC, you can pull from either hot leg to neutral and for 240VAC you pull from each hot leg. Think of two sine waves--the voltage from the peak of one sine wave to the zero line is 120VAC while the voltage from the peak of one wave to the trough of the other is 240VAC. Your SSRs can still cut just one hot leg, but the other leg will be a neutral for 120VAC or the other hot for 240VAC. I would recommend separate plugs for each voltage though--less chance of screw ups and the plug connectors are separately rated for voltage and amps.

In the pictures you can see the two 120VAC recepacles for heat sticks (each from a different hot leg) and one 240VAC receptacle for the HLT element along with the schematic showing how they're wired up.
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Old 01-31-2013, 08:49 PM   #9
BadNewsBrewery
 
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I was under the impression that OP wanted to run the same panel on a 120v feed OR a 240v feed depending on the size of the batch / where he was / what power was available. If the comment was to run one panel with a 120v feed AND a 240v feed at the SAME time, then ignore everything I said in my previous comment. Running both at the same time creates some issues with the GFCI side of things from what I understand.
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Old 01-31-2013, 09:51 PM   #10
hot_carl
 
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BadNews, you were right...I want to run EITHER 120 or 240 depending on where I am/which setup I use. I've included a verychildish looking wiring diagram (I'm at work and dont have access to anything to make it look nice). The design hinges on a 3 way switch with 2 NO contacts to activate the power input contactor for wither the 120 or the 240 feed depending on which is used. On the element out side there would be one unused contact in the plug, but this isnt and issue...there just wont be a wire in the element cable attached to it. I think this is close to exactly what jeffmeh was trying to explain, but I'm a visual person and needed to see it on paper...
File Type: pdf 240_120_wiring_diag.pdf (31.0 KB, 90 views)

 
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