Where to source electrical hardware

Discussion about EV/Battery charging infrastructure, Electric highways etc.
Post Reply
User avatar
jonescg
Senior Member
Posts: 1894
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Where to source electrical hardware

Post by jonescg » Mon, 28 Aug 2017, 21:16

Hi all,

I was wondering how I can go about searching for a DIN rail mounted changeover relay rated to 32 amps. I think it's known as a changeover relay, or DPDT, but rated to 500 V AC.
Double changeover relay.png
Double changeover relay.png (3.36 KiB) Viewed 307 times
The idea is to use it as a means to switch power from an inverter to a generator/grid supply. So the relay would have inverter L1 and N supplying terminals 1 and 3, while the grid/generator supply L1 and N at terminals 2 and 4. The output (terminals 5 and 6) is then fed into the household distribution board where the MCBs/RCDs are located. The coil (A1 and A2) would be supplied by the battery as a 12/24/48 volt supply and managed via the BMS as a low voltage cut-out.

I have found stacks of manual switches, including 3 phase variants, but these must go through a 0 position (presumably a break before make arrangement). I figure if the relay can react quickly enough most switchmode appliances would barely notice the dip.

Would Clipsal make something like this? ABB?
(Edited, got my makes and breaks wrong)
I challenge you to come up with a better invention than the bicycle

Rusdy
Groupie
Posts: 124
Joined: Mon, 09 Jun 2014, 16:45
Real Name: Rusdy
Location: Australia
Contact:

Re: Where to source electrical hardware

Post by Rusdy » Tue, 29 Aug 2017, 09:00

Good point, I've never seen such a high current rated relays (for AC circuit). Looks like you need to go the hard way, i.e. 2-off high current contactors (much easier to get) with modified control circuit (so that one contactor closes where the other opens).

User avatar
coulomb
Site Admin
Posts: 3020
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Re: Where to source electrical hardware

Post by coulomb » Tue, 29 Aug 2017, 09:55

I have a Hager ES470, 63 A changeover contactor. It has a mains voltage coil, but I'm sure you can get 24 V and 12 V versions [ edit: but not from Hager ]. Mine is there as a final keep-alive for power if the Monolith solar energy system is turned off or fails. I use a PIP-4048 to switch in the grid (it can also switch in a generator, obviously). Its relays are rated at 40 A.

Sorry, I don't recall where the Hager contactor came from. I'm pretty sure you can get them from electrical stores (in Queensland, that's Ideal / Rexel / John Turk and a few others). Wholesalers would certainly have them, but the question is will they sell to you in small quantities without setting up an account (but setting up an account may be painless and even convenient). In Queensland, that's Lawrence and Hanson. Maybe Schneider or ABB as well.

It switches over quite well (both the PIP changing over internally and the external Hager contactror). Usually no fridge or freezer motors drop out, certainly no computers ever restart. Often you can't even tell by the lights flickering, just the soft sound of the contactor pulling in or dropping out. Part of the reason for the smooth changeover may well be that the PIP synchronises its inverter with the mains (in frequency and phase but not in voltage). So most of the time, there is no abrupt change of phase, just a dead zone. Changeover contactors without this synchronisation can have a hard time switching inductive loads. It's not unknown for them to end up with welded contacts after some years of operation. This usually isn't catastrophic, but obviously has considerable nuisance value.

There are also the electronics online stores: RS Online, element14, Mouser, Digi-Key. All of these have a "presence" in Australia; some even have warehouses stocking the more popular items.

[ Edit: core -> coil, frequency but not phase -> frequency and phase but not voltage; deleted reference to swe-check (not relevant). ]
Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

User avatar
coulomb
Site Admin
Posts: 3020
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Re: Where to source electrical hardware

Post by coulomb » Tue, 29 Aug 2017, 10:09

I recall now how it was more difficult to get contacts rated over 25 A. But it can be done (it won't be cheap, but hopefully under or not much over AU$100).
Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

User avatar
jonescg
Senior Member
Posts: 1894
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Re: Where to source electrical hardware

Post by jonescg » Tue, 29 Aug 2017, 10:36

Thanks @coulomb ! I'll try Middys over here, but it does seem like a bit of a speciality item.

Especially if you consider the 3-phase options...
I did find this: https://www.alliedelec.com/abb-ns44es-20/70094437/ but it's only rated to 3 A!
I challenge you to come up with a better invention than the bicycle

User avatar
Richo
Senior Member
Posts: 2984
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Re: Where to source electrical hardware

Post by Richo » Tue, 29 Aug 2017, 12:34

Yeah middys is a good start.
Some of the cattledogs I have laying around call them an Automatic transfer switch.
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

User avatar
Richo
Senior Member
Posts: 2984
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Re: Where to source electrical hardware

Post by Richo » Tue, 29 Aug 2017, 12:41

Mouser have these:
P30P42D12P1-24 30A $183
ACC633U10 60A $312
Not DIN tho...
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

User avatar
Richo
Senior Member
Posts: 2984
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Re: Where to source electrical hardware

Post by Richo » Tue, 29 Aug 2017, 12:43

Actually the $180 one is SP3T-NO so not useful.
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

User avatar
weber
Site Admin
Posts: 2218
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Re: Where to source electrical hardware

Post by weber » Tue, 29 Aug 2017, 12:45

Hi Chris,

Typically, something switching that much power would be a "contactor" rather than a relay. Here's a description of the difference:
http://forums.aeva.asn.au/viewtopic.ph ... 089#p55089
And in a contactor, the contact arrangement you want is called "2NO+2NC". (two normally-open plus two normally-closed). You have to wire it to become a 2-pole changeover or DPDT.

On grid, the best way to do what you want to do, is not to have the BMS control the AC contactor, but to have the BMS control the inverter (even if only by disconnecting the battery), and then have the inverter control the AC contactor, by driving the contactor's coil from the inverter's 230 V AC output, via a suitable inline fuse. Then the inverter connects to the loads via the NO contacts, and the grid connects to the loads via the NC contacts.This avoids the need for control wires going into the AC switchboard, and it automatically switches to grid power if the inverter stops working for any reason.

Off grid, you would instead have the genset's 230 V AC output driving the coil, with the inverter connected via the NC contacts, and the genset via the NO.

In that case, you want a contactor with a 230 Vac coil, not 12 or 24 Vdc. The Hager 63 A 2NO+2NC contactor that coulomb mentioned is good, except it's an obsolete part number. The current version is the ESC465. You can see here that they don't offer anything smaller until you get down to 25 A. And you can see that coulomb is mistaken in thinking Hager also offer them with 12 V or 24 V coils. They have some contactors with 24 V AC coils, but none of these have 2NO+2NC and they have no contactors with DC coils. You can also see that their prices are insane.
http://www.hagerelectro.com.au/e-catalo ... /14166.htm
For those prices, you'd want their coils to have been rolled on the thighs of Cuban virgins. :o

If for some reason you really do need a 12 V DC or 24 V DC coil, I note that it is very difficult to find DIN-rail AC contactors of 25 A or more with such coils. The Hager solution is to use a 5 A relay with a 12/24 V AC/DC coil (EN145), to switch 230 V AC to the coils of the above contactors.
http://www.hagerelectro.com.au/e-catalo ... /14163.htm

The only direct solution I have found, after a lot of searching, is the Finder 22-series, available from Element 14.
http://au.element14.com/search?st=finder%20contactor
[Edit: Unfortunately, E14 don't carry any with contact rating above 25 A.]
The Finder 40 A 2NO+2NC with 12 V AC/DC coil is the 22.44.0.012.4620.
The Finder 40 A 2NO+2NC with 24 V AC/DC coil is the 22.44.0.024.4620.

And finally, we come to the part that I would recommend:
The Finder 40 A 2NO+2NC with 230 V AC/DC coil which is the 22.44.0.230.4620.
[Edit: Unfortunately I don't know where to order it. Let me know if you find somewhere.]
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

User avatar
jonescg
Senior Member
Posts: 1894
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Re: Where to source electrical hardware

Post by jonescg » Tue, 29 Aug 2017, 12:53

I think this makes sense:
ESC465.jpg
ESC465.jpg (103.27 KiB) Viewed 264 times
At least for a single phase arrangement.
I challenge you to come up with a better invention than the bicycle

User avatar
Richo
Senior Member
Posts: 2984
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Re: Where to source electrical hardware

Post by Richo » Tue, 29 Aug 2017, 13:00

ha ha even jaycar have them now (Non-DIN 20A).
MS5300 $200

ebay $75
302286272137

Cant find anything DIN rail tho...
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

User avatar
Richo
Senior Member
Posts: 2984
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Re: Where to source electrical hardware

Post by Richo » Tue, 29 Aug 2017, 13:01

weber wrote:
Tue, 29 Aug 2017, 12:45
...
And finally, we come to the part that I would recommend:
The Finder 40 A 2NO+2NC with 230 V AC/DC coil which is the 22.44.0.230.4620.
Unfortunately it's out of stock and not expected for 2 months.
I see some at RS 800-2874 $151+GST.
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

User avatar
weber
Site Admin
Posts: 2218
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Re: Where to source electrical hardware

Post by weber » Tue, 29 Aug 2017, 14:14

Well found (at RS) Richo. In fact I was wrong about them being expected at E14 in 2 months. E14 don't carry them at all. They don't carry any over 25 A.

Chris, I was about to post regarding the subtleties of the wiring arrangement. What you show would in fact be illegal, because it is dangerous under certain fault conditions. You must not switch the grid neutral, but you must switch the neutral of the other supply. And of course you must switch both actives. Using a 2NO+2NC contactor has an advantage over a DPDT relay in this case. The contact that would have switched the grid neutral can be paralleled with the other one for switching the grid active, to hopefully extend both their lives. The contacts that switch the inverter output are not so in need of reinforcement as they tend to be protected from high inrush currents by the output impedance of the inverter itself.

And why not show the inverter output also driving the contactor coil (via a small inline fuse).
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

User avatar
weber
Site Admin
Posts: 2218
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Re: Where to source electrical hardware

Post by weber » Tue, 29 Aug 2017, 15:54

Chris, To prevent fires, you also need to ensure that the contactor contacts can never carry continuous currents in excess of their 40 amp rating, sourced from either the inverter or the grid. There are various ways this can be done.

If the sum of the ratings of the circuit breakers on all the load circuits fed from the contactor happens to come to 40 A or less then you're done, provided the contactor is in the same switchboard as all of these breakers. A protection device is normally only considered to protect the cables and devices downstream from it, but AS3000 (sections 2.5.3.3 and 2.5.4.3) allows that they can protect conductors a very short distance upstream under conditions such as these.

If the total of the load circuits comes to more than 40 A, as it is perfectly entitled to do, thanks to "diversity", then you may need to provide additional protection for the contacts. The cable from the inverter has to be protected from overcurrent by some device in or near the inverter. If this device is rated at 40 A or less then it will also protect the contactor contacts that switch the inverter output. But the cable coming in from the street will usually only be protected by a fuse which may have a rating of 100 A or more (although 80 A is common). Even if you've paralleled the contacts for switching the grid active, as I suggested earlier, you can't really consider them as having twice the current rating, because one day one of those contacts may go high resistance and the other will be left holding the baby (or most of it). So, putting a 40 A breaker on the grid side of the contactor is the best way of dealing with this. If this is all happening in a sub-board, say in a shed, then the cable from the main board may already be protected by a breaker rated at 40 A or less, in which case no extra protection is needed.

By the way, when paralleling the contacts, the takeoff wires should be diagonally opposed, to maximise current sharing, in the same way you do when paralleling two battery cells.

I'm describing all this for the benefit of your electrician, who may not be familiar with contactor arrangements such as this. And of course the responsibility for the final arrangement is theirs, not mine. I note that I am not an electrician and am happy to be corrected if anyone thinks I'm misreading AS3000 here.
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

User avatar
jonescg
Senior Member
Posts: 1894
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Re: Where to source electrical hardware

Post by jonescg » Tue, 29 Aug 2017, 19:09

I think my image post appeared seconds after yours Dave, hence the A1 and A2 being still powered by the BMS/DC system. I have updated the image below:
ESC465 wiring.jpg
ESC465 wiring.jpg (106.62 KiB) Viewed 237 times
The grid neutral is permanently connected to the household loads (thanks for spotting that). The coil is powered by the inverter and the contacts are not doubles up inside the terminals (there would be a small busbar I presume?)

And yes, a fuse on the inverter output would be ideal. I would imagine you can put a lower current fuse in place of the existing 80 amp fuse?
I challenge you to come up with a better invention than the bicycle

User avatar
weber
Site Admin
Posts: 2218
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Re: Where to source electrical hardware

Post by weber » Tue, 29 Aug 2017, 20:50

jonescg wrote:
Tue, 29 Aug 2017, 19:09
I would imagine you can put a lower current fuse in place of the existing 80 amp fuse?
The pole or pillar fuse belongs to the electricity distributor. Only they can change it. You could just use a 40 A breaker for your main switch. But normally you won't want to do that because you will have some high powered appliances, such as aircon or stove, that you will not want to run off the inverter. So you will just put a 40 A breaker between the main switch and the contactor.
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

User avatar
coulomb
Site Admin
Posts: 3020
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Re: Where to source electrical hardware

Post by coulomb » Tue, 29 Aug 2017, 21:33

jonescg wrote:
Tue, 29 Aug 2017, 19:09
I would imagine you can put a lower current fuse in place of the existing 80 amp fuse?
Err, I suppose so, in a theoretical sense. But I'd say it would be severely frowned upon. That fuse is in your "toadstool" if you have underground power, or up on a pole if it's overhead power. And of course the conductors on the other side of the fuse have ferocious fault currents (thousands of amps), so it's enough to make grown electricians timid. I would recommend against that.

Another 40 A breaker isn't going to break the bank, so to speak. Of course, if your switchbox is full, then it's a pain, but your electrician can usually add a small inexpensive (as these things go) dinrail enclosure that holds only 2 breakers.

Earlier when I mentioned the availability of contactors with 24 V and 12 V coils, I didn't mean to imply that they would be available from Hager specifically. They would be branded ABB, Legrand, etc. At the QUT microgrid we used quite a lot of contactors with 24 VDC coils, and some of them had respectable current ratings. However, they were mostly 3PST or 4PST, for three phase work. We didn't have an application for normally closed contacts. By the way, some of those cost around $700, so when one blew up that I was working with, we tried really hard to figure out how not to blow up its replacement. In the end, we decided it was bad luck and/or poor build quality, but we added some varistors for good measure. We didn't replace the contactor with the one of same brand :!:
Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

Post Reply