Electric ULWD Element + Winch Diagram

[GarrettVD]

Hi all,
Currently working on an automated brewing system, controlled through my Raspberry pi, some shift registers, relays, etc. Currently trying to sort out how I want to wire the high voltage components, such as the 40A AC 5500Watt, 240V ULWD element, and the 120V AC Winch to raise and lower my grain basket.

I am not an electrician, and I'd like to make sure I am wiring this correctly. My brother is, however, and I have been working with him on and off, but he hasn't had time to fully review the diagram.

So, how does my diagram look? Both the winch and the element are fed from the same 240V power source, though it's worth mentioning they will not operate at the same time.

How does it look?



Cheers,

 

[tyzippers]

Garrett, you're close here, but I do see some issues you may need to correct. I would like to know a few things:

1: Is the top switch being used to kill power to the element via the contactor?
2: Where is the power coming from on the relay board to power the contactors?
3: Did you have a reason for putting an SSR on the winch UP/DOWN lines?

Some recommendations:

1: First and foremost, please make sure this control circuit is protected by a GFCI breaker! This is of paramount importance for your safety!
2: The fuses supplying the element power will not be adequate. These should by a double pole circuit breaker rated for 30A for a 5500W 240V ULWD heating element. The element will draw around 23 amps at full load which will trip your 20A fuses.
3: Your winch should also be protected by an adequate circuit breaker on its own branch.
4: You really don't need an SSR on the winch UP/DOWN lines. A contactor will suffice.
5: Depending on your winch diagram (which I do not have) it would seem to me that the other terminal of the winch UP/DOWN inputs should be connected to neutral and not ground.
6: You should also have a 1A fuse protecting the power supplying the contactor coils.

These are the issues that stand out right away. This is certainly doable! We can fix this up!

 

[GarrettVD]

Thanks for the response! Great advice here; I'll review this evening when I have some time. The SSR is to control the raising / lowering; but I've taking the hoist part of it out for the time being. Just focussing on the element for now. The power for the relay board is coming from a DC power source; basically just controlling the SSRs from that source.

I calculated a ~22A draw total for the element; would that not be 11A per 120V line?

Thanks!

Garrett, you're close here, but I do see some issues you may need to correct. I would like to know a few things:

1: Is the top switch being used to kill power to the element via the contactor?
2: Where is the power coming from on the relay board to power the contactors?
3: Did you have a reason for putting an SSR on the winch UP/DOWN lines?

Some recommendations:

1: First and foremost, please make sure this control circuit is protected by a GFCI breaker! This is of paramount importance for your safety!
2: The fuses supplying the element power will not be adequate. These should by a double pole circuit breaker rated for 30A for a 5500W 240V ULWD heating element. The element will draw around 23 amps at full load which will trip your 20A fuses.
3: Your winch should also be protected by an adequate circuit breaker on its own branch.
4: You really don't need an SSR on the winch UP/DOWN lines. A contactor will suffice.
5: Depending on your winch diagram (which I do not have) it would seem to me that the other terminal of the winch UP/DOWN inputs should be connected to neutral and not ground.
6: You should also have a 1A fuse protecting the power supplying the contactor coils.

These are the issues that stand out right away. This is certainly doable! We can fix this up!

 

[tyzippers]

Thanks for the response! Great advice here; I'll review this evening when I have some time. The SSR is to control the raising / lowering; but I've taking the hoist part of it out for the time being. Just focussing on the element for now. The power for the relay board is coming from a DC power source; basically just controlling the SSRs from that source.

What I was getting at is that you ONLY need a contactor to control the UP/DOWN motion of the winch. These contactors will not be switched on/off at a high rate of speed or even all that often. An SSR is not necessary in this case. SSRs are used because they have the ability to switch on/off faster and more often for a longer period of time before failing since they are all solid state and not mechanical. That's why they are used to control the on/off of the heating element which will be cycled FREQUENTLY in a brew session. You will be OK to eliminate the SSRs from the winch control circuit.

I calculated a ~22A draw total for the element; would that not be 11A per 120V line?

Thanks!

I'm not sure how you calculated ~22A for the element. We may be splitting hairs here, but with Ohm's law stating that P=IV and I= P/V, you get,

I=5500W/240V
I=22.917A

rounding up in this case, ~23A draw for the element.

Now, in a 240V single phase circuit, the Voltage is additive per leg, i.e. Leg 1 + Leg 2=120V+120V=240V, but the amperage is not. Each wire in the 240V circuit will see the total current draw similar to the way the LINE and NEUTRAL wire will both see the full amperage in a 120V single phase circuit. So, when I say you need a 30A Double Pole circuit breaker, each circuit breaker in the pair are rated for 30A, NOT 15A. You also DO want the double pole breaker so that both legs are isolated if there is an overcurrent condition in the circuit.

And as always, please make sure the panel is GFCI protected!

Hope this clarifies my earlier remarks!

 

[jeffmeh]

Thanks for the response! Great advice here; I'll review this evening when I have some time. The SSR is to control the raising / lowering; but I've taking the hoist part of it out for the time being. Just focussing on the element for now. The power for the relay board is coming from a DC power source; basically just controlling the SSRs from that source.

I calculated a ~22A draw total for the element; would that not be 11A per 120V line?

Thanks!

A 5500w element divided by 240v =~ 23a. That is across both lines of the 240v circuit. You need 10awg copper wiring.

 

[GarrettVD]

I am more or less using the SSR's to control the up/down from the relay using a 12VDC source; I am not sure how I could wire that with just a contactor?

Thank you for the explaination regarding amperage; that makes total sense now.

I will ensure that the circuit is GFCI protected.

Thanks,

What I was getting at is that you ONLY need a contactor to control the UP/DOWN motion of the winch. These contactors will not be switched on/off at a high rate of speed or even all that often. An SSR is not necessary in this case. SSRs are used because they have the ability to switch on/off faster and more often for a longer period of time before failing since they are all solid state and not mechanical. That's why they are used to control the on/off of the heating element which will be cycled FREQUENTLY in a brew session. You will be OK to eliminate the SSRs from the winch control circuit.



I'm not sure how you calculated ~22A for the element. We may be splitting hairs here, but with Ohm's law stating that P=IV and I= P/V, you get,

I=5500W/240V
I=22.917A

rounding up in this case, ~23A draw for the element.

Now, in a 240V single phase circuit, the Voltage is additive per leg, i.e. Leg 1 + Leg 2=120V+120V=240V, but the amperage is not. Each wire in the 240V circuit will see the total current draw similar to the way the LINE and NEUTRAL wire will both see the full amperage in a 120V single phase circuit. So, when I say you need a 30A Double Pole circuit breaker, each circuit breaker in the pair are rated for 30A, NOT 15A. You also DO want the double pole breaker so that both legs are isolated if there is an overcurrent condition in the circuit.

And as always, please make sure the panel is GFCI protected!

Hope this clarifies my earlier remarks!

 

[tyzippers]

I am more or less using the SSR's to control the up/down from the relay using a 12VDC source; I am not sure how I could wire that with just a contactor?

Thank you for the explaination regarding amperage; that makes total sense now.

I will ensure that the circuit is GFCI protected.

Thanks,

You're most certainly welcome!

Regarding the SSRs vs contactors, you can find contactors that are available that operate on 12VDC. I'll see if I can find some sources.

 

[GarrettVD]

You're most certainly welcome!

Regarding the SSRs vs contactors, you can find contactors that are available that operate on 12VDC. I'll see if I can find some sources.

Thanks buddy! No worries, I can take a look. Great advice!

Re: GFCI breaker; my panel definitely has one, so I'm safe there.

Cheers!

 

[tyzippers]

Thanks buddy! No worries, I can take a look. Great advice!

Re: GFCI breaker; my panel definitely has one, so I'm safe there.

Cheers!

You're welcome! I lost my day today and didn't have much time to do any looking around.

Glad to hear you got protection! This is one situation a rubber won't help!

Good luck!

 

[GarrettVD]

Too true

I'm going to upload a new diagram tomorrow morning; however, one more quick question! I have a SPST switch rated for 20A; but, that is too low for my circuit, I'm going to need a 23A-25A switch, correct? Any idea where I can purchase a SPST or DPST toggle switch? I have been looking at Newark Canada, but oddly enough they don't seem to have what I need here.

Cheers

 

[tyzippers]

Too true

I'm going to upload a new diagram tomorrow morning; however, one more quick question! I have a SPST switch rated for 20A; but, that is too low for my circuit, I'm going to need a 23A-25A switch, correct? Any idea where I can purchase a SPST or DPST toggle switch? I have been looking at Newark Canada, but oddly enough they don't seem to have what I need here.

Cheers

I'll look for your new diagram when you get it uploaded.

As for the switch, I'm assuming you're talking about the switch that actuates the contactor for the element? If that's the case, then the switch should be moved to the contactor coil circuit which is a significantly lower current draw (< 1A). In this case, a typical toggle switch or whatever type of switch you choose to use should work to control the contactor. There's no need for a switch rated at 30A.

 

[jeffmeh]

It's nowhere near as pretty and slick looking as a small switch that energizes a contactor, but you can also use a suitably rated switch. http://www.homedepot.com/p/Leviton-...ble-Pole-Switch-White-R62-03032-2WS/100356941

 

[GarrettVD]

It's nowhere near as pretty and slick looking as a small switch that energizes a contactor, but you can also use a suitably rated switch. http://www.homedepot.com/p/Leviton-...ble-Pole-Switch-White-R62-03032-2WS/100356941

I am looking for something like that for the an emergency shutoff; but my goal is to have it all controlled via a relay board, and then through my Raspberry Pi.

I've put together a new diagram; swapped the hoist for a wiper motor controlled by a 12VDC power supply; either going to use an old PC power supply or a 12VDC, 5A power supply for a laptop. only parts I am missing at the moment are the double pole, single throw 12VDC contactors to reverse the polarity on the wiper motor.; I can source SPST ones pretty easily, but the DPST ones seem to be very expensive and hard to find. I might have to use for SPST ones. Any tips there would be great.

Cheers

 

[tyzippers]

I am looking for something like that for the an emergency shutoff; but my goal is to have it all controlled via a relay board, and then through my Raspberry Pi.

I've put together a new diagram; swapped the hoist for a wiper motor controlled by a 12VDC power supply; either going to use an old PC power supply or a 12VDC, 5A power supply for a laptop. only parts I am missing at the moment are the double pole, single throw 12VDC contactors to reverse the polarity on the wiper motor.; I can source SPST ones pretty easily, but the DPST ones seem to be very expensive and hard to find. I might have to use for SPST ones. Any tips there would be great.

Cheers

There's still a couple issues with your schematic Garrett. First, the switch on the heating element contactor should be located between the 1A fuse and the contactor coil. Second, the supply for the coil should be tapped before the SSR, not after it. Otherwise, the contactor would be switching on and off with the SSR when the switch was on. This is not advisable at all.

As another side note, I think what Jeffmeh was saying in post #12 is that you could replace the small switch/contactor combo with the 30A switch he linked to. It's not as elegant and would consume more space on the control panel, but it would work.

As for the wiper motor control, your schematic should work. For that low voltage circuit you don't need contactors in the sense that you're thinking. Using a simple DPST relay would work. I reckon you should be able to source a couple of those for pretty cheap. You could try Radio Shack, but I would try Automation Direct, DigiKey, or Mouser. There may be other sources as well if you look (eBay, Amazon).

 

[GarrettVD]

Thanks for the suggestions, Tyzippers!

Just wanted to post a bit of an update. Lots of progress over the past couple of weeks. Have the keg retrofitted with element, etc. Almost done with the electrical stuff; just waiting on my 12VDC 5A power adapter to come in for the motor. Also waiting for my load sensor, instrumentation amp and ATD chip to come in; really wish the raspberry pi had ATD built right in like the Arduino; but alas, it doesn't.

"Orchestration" script (ie. what open and closes the valves at set intervals, detects temperature, load, controls relays, etc.) is pretty much done. I've made the shift register + gpio library publicly available under BSD licensing, if anyone is interested in using it in their project (node.js module).

Here are some photos of the diagram, temporary electrical layout (def. not final! I'll be putting all the components in a waterproof box) and the keggle itself. (Also note the I did move the switch between the 1A fuse and the coil)

 

[tyzippers]

If I may interject once again, I still see some problems with the schematic. I will detail what I'm talking about once I get to work. Typing it out on my phone is a pain!

 

[tyzippers]

Thanks for the suggestions, Tyzippers!

Just wanted to post a bit of an update. Lots of progress over the past couple of weeks. Have the keg retrofitted with element, etc. Almost done with the electrical stuff; just waiting on my 12VDC 5A power adapter to come in for the motor. Also waiting for my load sensor, instrumentation amp and ATD chip to come in; really wish the raspberry pi had ATD built right in like the Arduino; but alas, it doesn't.

"Orchestration" script (ie. what open and closes the valves at set intervals, detects temperature, load, controls relays, etc.) is pretty much done. I've made the shift register + gpio library publicly available under BSD licensing, if anyone is interested in using it in their project (node.js module).

Here are some photos of the diagram, temporary electrical layout (def. not final! I'll be putting all the components in a waterproof box) and the keggle itself. (Also note the I did move the switch between the 1A fuse and the coil)

Ok, Garrett. I think it's absolutely awesome that you're making good progress on this project! I can't wait to see the completed product!

Anyway, as I said, I saw a few issues with the schematic.

1) There needs to be a fuse on both hot legs of the heating element at the very least. I'd still like to see a coupled circuit breaker so that if one side goes, they both go.

2) You should move the 1A fuse on the control circuit to the other side of the switch. In other words, the fuse is the first thing in the circuit.

3) In regards to the 12VDC power: The adapter should receive one leg of 120V just as you have it shown. Also, it will need a Neutral supplied to it as well. On the DC side, The +12VDC should be OK the way you have it routed. The Common terminal of the wiper motor should be connected to the common, or 0V, terminal of the 12V power supply, not ground as you have it shown.

Hope this helps!!

 

[GarrettVD]

Thanks buddy!

Yeah Ive corrected the 1A fuse configuration a few
Days ago; should be good now. Ive ordered a 2 pole GFCI for the extra assurance like you say. And also some diode rectifiers for the hoist.

Cheers

Ok, Garrett. I think it's absolutely awesome that you're making good progress on this project! I can't wait to see the completed product!

Anyway, as I said, I saw a few issues with the schematic.

1) There needs to be a fuse on both hot legs of the heating element at the very least. I'd still like to see a coupled circuit breaker so that if one side goes, they both go.

2) You should move the 1A fuse on the control circuit to the other side of the switch. In other words, the fuse is the first thing in the circuit.

3) In regards to the 12VDC power: The adapter should receive one leg of 120V just as you have it shown. Also, it will need a Neutral supplied to it as well. On the DC side, The +12VDC should be OK the way you have it routed. The Common terminal of the wiper motor should be connected to the common, or 0V, terminal of the 12V power supply, not ground as you have it shown.

Hope this helps!!

 

[tyzippers]

Glad to help Garrett!