Some Brew Panel questions

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jamieN
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Some Brew Panel questions

Post by jamieN » Sun Jun 23, 2019 11:21 am

Been slowly getting parts for a panel build heres what I have
All switches and LEDs
3 x Inkbird PIDs with 25A ssrs some crappy K-type probes which will be changed for PT100 probes.
That was the easy part it's the inside that's got me a bit confused.
Electric Brewery site says to use 30A relays but from what I've read on here it seems to be 25A 2pole contractor which i assume would be NO the circuit is controlled by the switches and PID.
Been looking on aliexpress as there seems to be very similar items on ebay. Is there electrical gear safe if you read others reviews on items they seem up to standard.
Many more questions to follow.

Thanks jamie
Last edited by jamieN on Wed Jun 26, 2019 2:06 pm, edited 1 time in total.

jamieN
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Re: Some Brew Panel questions

Post by jamieN » Sun Jun 23, 2019 1:10 pm

Is this the right contactor £3.65 13%OFF | Free Shipping GPCT1 2P 16A 25A 220V/230V 50/60HZ Din Rail Household Ac Contactor 2NO for Household Home Hotel Resturant
https://s.click.aliexpress.com/e/bHw009HA
Also for the terminal bus would these do with the correct jumper connectors£1.43 11%OFF | 10Pcs 1 Pin Din rail Universal compact wire wiring connector conductor terminal block with lever
https://s.click.aliexpress.com/e/befZ2nNq.

Forgot to add my intention is to use 3kw elements from brewbuilder or angel hence the reason I have gone 25A. Also I dont think a timer is needed as I use beersmith whilst brewing so it would be a pointless item in my eyes

Jamie

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Kev888
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Re: Some Brew Panel questions

Post by Kev888 » Wed Jun 26, 2019 1:48 pm

Those links just take me to a general aliexpress page, rather than specific products. However as general observations: the sustained current that each element will draw will be (roughly) 13amps so even allowing a bit of extra leeway 25a switches at about 240v should be more than sufficient, even 16amp at 240Vac (or more) should be really.

I haven't read the EB site but if they suggest 30amp switches then I wonder if they might be using 110v (and so running higher currents)? Another possibility is the switches control more than one element at once - though if that is your intention in the UK, you would need to power the panel from industrial sockets or something.

Unfortunately, buying chinese/ebay/ali switches is something of a lottery even if they 'appear' to be branded; I've had several that just haven't lived up to their specified rating (let alone longevity). So it would be best to use the exact same items that have worked for others if you can find any, or else buy from reputable component retailers who source direct from decent manufacturers. Alternatively, use the switch to operate a power relay rather than taking the load directly; more complication but it widens the options for panel switches.
Kev

jamieN
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Re: Some Brew Panel questions

Post by jamieN » Wed Jun 26, 2019 2:06 pm

Sorry about the links thought they work when I click them but I've got the app on my phone and it takes me to the items.
The Electric Brewery uses 5500kw elements so that will be why he uses 30A relays for his build. I thought other used contractors in place of the relays as they were more readily available and did the same job.

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PeeBee
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Re: Some Brew Panel questions

Post by PeeBee » Wed Jun 26, 2019 3:02 pm

The "Electric Brewery" has a lot to answer for over here! The reason you can't find 30A relays is because we are a bit more sophisticated over here and use a device called a "contactor" and you'd probably get a 40A one. That would have been my stock answer, but the last relay I got was 40A (Chinese import). "Contactors" are little more than heavy- (they are literally heavy!) duty relays. They don't spark and flash like ordinary relays. They are popular in our crowded island because they don't cause the radio interference and upset the neighbours.

They are a bit "blockier" than ordinary relays but often come in a DIN rail package (the ones described by "Electric Brewery" require separate DIN rail sockets).
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Re: Some Brew Panel questions

Post by Heron1952 » Wed Jun 26, 2019 3:42 pm

FWIW I used these still ok 12 months on
https://www.ebay.co.uk/itm/JQX-40F-2Z-C ... 2749.l2649
aka Rhys

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Re: Some Brew Panel questions

Post by PeeBee » Wed Jun 26, 2019 4:32 pm

Heron1952 wrote:
Wed Jun 26, 2019 3:42 pm
FWIW I used these still ok 12 months on
https://www.ebay.co.uk/itm/JQX-40F-2Z-C ... 2749.l2649
Got my Chinese "40A" relay off eBay too. It was much simpler a couple of years and more ago: You could only get 16A (max) relays, and for everything else there was "contactors". Now a quick search on eBay and you can find just what you want from those lovely people in China who have our best interests at heart … scary isn't it?

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Re: Some Brew Panel questions

Post by themadhippy » Wed Jun 26, 2019 4:44 pm

They don't spark and flash like ordinary relays. They are popular in our crowded island because they don't cause the radio interference and upset the neighbours.
Dont they? Youve obviously not played with industrial electrickery.The term relay and contactor is pretty interchangeable,you can get a 5A contactor or a 30A relay,about the only difference is a contactor normally has the facility to have overload protection easily added .
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Re: Some Brew Panel questions

Post by Kev888 » Wed Jun 26, 2019 5:29 pm

Yes, for switching individual 3kw elements then either should work; I assume the SSRs will be doing any rapid switching, and so the contactor/relay will just be for manual or low rate on/off type switching?

If so, then the most economic option might be a decent brand, decent quality power relay at around 16Amps or so, probably around three or four quid each. Relays are readily available at much higher ratings too, and extra capacity is always nice, but then (or if more industrial packaging/mounting options were preferred) perhaps contactors would indeed start to become similar (or better) value.
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Re: Some Brew Panel questions

Post by PeeBee » Wed Jun 26, 2019 5:35 pm

themadhippy wrote:
Wed Jun 26, 2019 4:44 pm
Dont they? Youve obviously not played with industrial electrickery.The term relay and contactor is pretty interchangeable,you can get a 5A contactor or a 30A relay,about the only difference is a contactor normally has the facility to have overload protection easily added .
Shhh. I'm trying to build a convincing argument for doing things "right".

Contactors are a bit of "using a sledgehammer to break a nut". When you shake them you can hear the sledgehammer!

Never heard of 5A contactors? Bet you can't buy Chinese ones on eBay. Most Chinese ones (relays or contactors) would almost safely handle 5A, perhaps, but they'll all be labelled 40A.

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Re: Some Brew Panel questions

Post by PeeBee » Thu Jun 27, 2019 12:42 pm

As "themadhippy" points out, the term relay and contactor is pretty interchangeable, so I thought I'd do a bit of revision and define the differences. What follows is my take on the differences! The "facts" have all got a bit smudged and I couldn't find a "definitive" guide on the Web to link. You will certainly find exceptions to what I list next:


In a relay the solenoid acts directly on the switch arms which will be bendy leaf spring arrangements. In a contactor the solenoid acts on a solid "core" or "shaft" which moves the (unbending) switch contacts (perhaps multiple pairs of contacts) to and fro. As a result most relays are two-way (changeover) and most contactors are single way (on or off, but frequently multi-poled).

As the contacts of either close they will arc. In a flimsy relay the arcing interrupts the closing of the light weight contacts and the arcing holds the contacts open for a split-second, allowing more arcing, etc. The heavier contactor switch contacts have a bit of momentum to counter that.

Arcing not only causes radio interference but also erodes the contacts (they wear out!).

It's not all plain sailing for the contactor. The extra weight of the contacts in a contactor (and more weight may be added to make the switch more "definite") requires a stronger solenoid, that draws more power, and would burn out quicker than a relay coil. So the solenoid might only be momentary and once the switch is "switched" a secondary, weaker, "latching" coil takes over to keep the contacts closed. The extra weight also carries momentum and may cause the contacts to bounce, resulting in more arcing, so some form of dampening is required.

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Re: Some Brew Panel questions

Post by PeeBee » Thu Jun 27, 2019 1:43 pm

I think it's hilarious that we've two characters supposedly offering advice on dangerous high powered electric circuits - one calls himself "themadhippy" and the other (me!) has an avatar frequently described as a "caricature", and if that isn't enough carries an ID card so the police can be prepared should they haul me up … because I'm … err … mad?

I think "Kev888" is safe?

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Re: Some Brew Panel questions

Post by jamieN » Thu Jun 27, 2019 3:08 pm

Dont know where to start here there seems to be a preferred method for people some use relays bit of a downside is you need a socket for a din rail fitting or a contactor which has the din rail part already there.
In my eyes a contactor makes sense as they have din rail fitting as standard. Which takes out the need for many holes drilled and tapped for each item to be fitted and they can be easy changed out if problems arise.
The SSRs will be doing the switching.
A 40A relay seems over kill as I don't intend to go higher power as I'm only going to do 6 gal batches any bigger and it would be shame if the brew wasn't the best.
Overload protection would be taken care of by an mcb.
As youse can guess I'm not a sparky but a mere pipefitter welder and nuts and bolts kind of guy. Basic electrics I can do but this is a bit over my head for now.

Jamie

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Re: Some Brew Panel questions

Post by PeeBee » Thu Jun 27, 2019 3:43 pm

jamieN wrote:
Thu Jun 27, 2019 3:08 pm
Dont know where to start here there seems to be …
DIN rail Contactors are commonly available as 25A as well as 40A. But the physical sizes are standard so you wont gain anything in size (relay DIN rail mounts will most likely be the same width). You will get 25A contactors at half the width if you elect to switch only the live line (the one in the piccy above can switch both live and neutral lines).

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Re: Some Brew Panel questions

Post by Kev888 » Thu Jun 27, 2019 4:44 pm

jamieN wrote:
Thu Jun 27, 2019 3:08 pm
Dont know where to start here there seems to be a preferred method for people some use relays bit of a downside is you need a socket for a din rail fitting or a contactor which has the din rail part already there.
In my eyes a contactor makes sense as they have din rail fitting as standard. Which takes out the need for many holes drilled and tapped for each item to be fitted and they can be easy changed out if problems arise.
The SSRs will be doing the switching.
A 40A relay seems over kill as I don't intend to go higher power as I'm only going to do 6 gal batches any bigger and it would be shame if the brew wasn't the best.
Overload protection would be taken care of by an mcb.
As youse can guess I'm not a sparky but a mere pipefitter welder and nuts and bolts kind of guy. Basic electrics I can do but this is a bit over my head for now.

Jamie
Based on that, either relays or contactors could be made to do the job, so its just about configuration really:

I would choose a contactor if I wanted a simple, robust open/close switch to mount to a DIN rail directly. From the above, this sounds like it is what you want, really. Something like 25amps would be more than enough.

I might choose a relay if I wanted more poles or throws than common open/close contactors offer, particularly in a small space. Or if I wanted something very cheap and compact (e.g. a 16amp relay used without a socket), but that doesn't sound like what you want here.
Kev

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