might be going electric

[mb-squared]

It looks like I might be making the move from gas to electric and am hoping to get some feedback before I get too far. I have an electrician friend who will be signing off on the final product, but I am hoping to avoid bugging him too much at this early stage.

I already have a BCS, so I'll incorporate that into this new control panel. I have two 32A circuits in my brew room, one for the HLT and one for BK. I've attached a diagram of the circuitry for the BK (to keep the diagram relatively simple), but this same circuitry will be duplicated for the HLT. The main idea here is to use two contactors in conjunction with a 3-way switch to run the BK either manually or automatically via the BCS. The thick lines represent 6mm2 cable; the thin lines represent 2.5mm2 cable.

I'd really appreciate any feedback from those who have gone down this path before and have a pretty good idea of how to keep my sparky friend from pissing himself with laughter when he sees what I've done.

Cheers,

matto

 

[mrsupraboy]

What's a bcs

 

[mb-squared]

basically 4 PIDs in one. Info here: http://www.embeddedcontrolconcepts.com/

 

[Camo6]

Two 32A circuits? Lucky *******.
Haven't the expertise to advise, only that you should be sure to ground the SSR base as well.
Once more, lucky *******.

 

[mb-squared]

Hi Camo6, that's a good idea. I haven't seen anyone ground their SSR's before (going by the popular electric brewing sites), but it does seem like a good idea now that you mention it.

Cheers,

 

[brewermp]

Not sure if it goes into detail but have you had a look at this site?

http://www.theelectricbrewery.com/

 

[Bribie G]

basically 4 PIDs in one. Info here: http://www.embeddedcontrolconcepts.com/

What's a PID? Will it improve my scores in the competitions this year?

Here's my electric controller:



urn on, urn off.

B)

 

[squirt in the turns]

Disclaimer: I'm a total amateur and not qualified in any way.

Looks good to me, mb-squared. I'd say it's ready to show your sparky mate, without any expectation of pissing. As Camo said, earth the SSR. The only other advice I'd offer is consider using a DC signal to trigger the relays, so the switch you're touching only has low voltage DC running through it (a minor safety consideration). I believe the BCS requires (comes with?) a DC power supply so you'll have one in the box anyway.

Also maybe add an emergency stop button.

 

[mb-squared]

What's a PID? Will it improve my scores in the competitions this year?

Here's my electric controller:

power point.jpg

urn on, urn off.

B)

Nice one. I suppose temperature control is a passing fad. probably shouldn't be so keen to jump on the silly bandwagon.

 

[mb-squared]

Disclaimer: I'm a total amateur and not qualified in any way.

Looks good to me, mb-squared. I'd say it's ready to show your sparky mate, without any expectation of pissing. As Camo said, earth the SSR. The only other advice I'd offer is consider using a DC signal to trigger the relays, so the switch you're touching only has low voltage DC running through it (a minor safety consideration). I believe the BCS requires (comes with?) a DC power supply so you'll have one in the box anyway.

Also maybe add an emergency stop button.

Thanks squirt, I've thought about the emergency stop button. And they certainly are popular. But I've been brewing with my BCS (albeit with gas burners) for quite some time and have never had the need to hit the 'oh shit' button. I wonder if anyone has ever had to hit it and what the unfortunate circumstances were?

Anyway, if I were to put it in, would you put it between the 3-way switch and the contactors? I've revised the drawing to reflect that option. Is that how you would do it? Thanks for your suggestions.

Cheers,

 

[Wrayza]

I'd remove your 2.5mm control wiring from that 32amp RCD combo and put it on a smaller dedicated RCD.

You could also do away with one of the contactors. Have power always present at the SSR and a two position switch that drops in your manual contractor. The SSR won't mind having power at its output when it should be normally open.

Downside, you would need another two position switch to break the supply between your BCS and SSR to achieve 'off'.

Upside, save $ on a contactor and cut down considerably on enclosure size.

 

[mb-squared]

I'd remove your 2.5mm control wiring from that 32amp RCD combo and put it on a smaller dedicated RCD.

Thanks for that. It makes a lot of sense. I've updated the drawing. I've also put in an in-line fuse for the indicator light.

As for doing away with one of the contactors, I see what you are saying and that is a good idea too. But I've already ordered them (along with a big enough enclosure), so I'll stay with two contactors as long as it's safe.

Cheers,

 

[Wrayza]

Spot on, better not to break gauge without correct circuit protection. Inline fuse is fine too.

Nothing wrong with the two contactors if you've already ordered them.

 

[squirt in the turns]

Thanks squirt, I've thought about the emergency stop button. And they certainly are popular. But I've been brewing with my BCS (albeit with gas burners) for quite some time and have never had the need to hit the 'oh shit' button. I wonder if anyone has ever had to hit it and what the unfortunate circumstances were?

Anyway, if I were to put it in, would you put it between the 3-way switch and the contactors? I've revised the drawing to reflect that option. Is that how you would do it? Thanks for your suggestions.

Cheers,

You're probably right about the e-stop, although I can tell you about a circumstance in which I wish I'd had one: I was running a 2400W kettle element through a control panel which used a C14 socket (with a built in fuse holder and 10A fuse) as the inlet, supposedly rated for 10A but probably not continuous duty at that level of current. Near the end of an hour boil, the socket melted and caught fire, without blowing the fuse or tripping the 10A RCBO, so everything was actually still working. If I'd had an e-stop button I'd have been hitting pretty hard at that point. As it was, I was scrambling to switch it off at the mains.

Could you get a 32A double-pole e-stop switch and put it directly after the terminal block? You could cut both the active and neutral that way, completely de-energising the entire panel, to be extra safe. That way if your relays fail and get stuck closed (rare but can happen), the e-stop will still kill power to the SSR and element.

 

[Wrayza]

That would be one expensive stop switch, cheapest option if you're after this feature would be mount your 32A and 8A breakers on din rail fixed to a hat section so they protrude through your enclosure door or face plate. Just like a switch board.

 

[Pokey]

That would be one expensive stop switch, cheapest option if you're after this feature would be mount your 32A and 8A breakers on din rail fixed to a hat section so they protrude through your enclosure door or face plate. Just like a switch board.

That would not be water proof, so probably not a great idea.

Personally I wouldn't bother with the terminal bars, just loop the wires between the devices.

The ssr is not an isolation device, if you plan on touching any parts of your equipment without unplugging keep the contactor.

You need seperate protection on the 2.5 wire, a circuit breaker is much more convenient to reset than a fuse.

 

[mb-squared]

Thanks for all the feedback guys, very helpful.

Squirt, thanks for sharing your tale of woe. It definitely highlights the need to terminate things in a hurry. In my case, though, my control panel will be powered by two 32A powerpoints (see here) that are within an arm's length of the control panel and brew rig. So if I see smoke, I can just reach over and flip those two switches very easily.

Wrayza, nice idea, but like Pokey says, not water proof, so I think I'll keep everything contained.

Pokey, I definitely agree that the SSR is not an isolation device -- thus my reason for the contactors. I take your last comment to mean that I should ditch the in-line fuse for a circuit breaker. Easy enough to do. And, you're right, much easier to deal with in the unlikely case that it trips.

Cheers boys, I feel like I'm ready to get to get to work and that my sparky mate won't be too exasperated with my efforts.

matto

 

[TheWiggman]

* Not an electrician *

Looks sensible to me. My preference - if you are going to call it an 'E-stop' - is to isolate at the incoming lines rather than the feed to the contactors. If one of the contactors crapped itself and melted closed the e-stop won't work. You could only isolate the active but leave this up to your sparky mate to determine, he'll know the standard/s and best practice.

 

[dave81]

The way to do what you want mb is to have a control circuit
Run the mains into a a contactor tap into the line side through a fuse through the e stop and a on off switch and supply the contactor coil this will achieve your double pole isolation of the whole panel

 

[MastersBrewery]

mb,
What brew length are you looking at? I'm using 4800w of heating elements and having run it through it's paces I'd say I'll get 90L to a rolling boil nicely, though I'm mainly set for 40l Batches(cold side).

Mike