Change over relay

[tangledfooted]

Hi

Just taken possession of 39ft wide beam Broads Cruiser and a CRT mooring on the River Lee with no shoreline. Along with many other tasks I need to re do the AC system to run of an inverter and Generator and like the look of the circuit diagram here My link the one with a 4 pole change over relay.

 

System set up so far : Generator 5KW kipor deisel 240v ac to be run every other day or so to charge up the batteries and do the laundry/vacuum the boat etc. I've got 300 AHrs of 12v sealed Lead acid battery, a 40Amp Mastervolt charger and 2000 W pure sine wave inverter again from Mastervolt.

 

So you can see I've just about run out of money and don't want to buy 2 RCD/MCB units (space and money) so I like the look of the 4 pole switching circuit discribed on smartgauge the automatic one with a relay rather than a switch. My question is where can I get one and what am i looking for. I've been looking for a 14pin 4PDT Power relay 240V 32A, is this what Im after? Could I use 2 x 2PDT power relay? The nearest I've found is thisMy link but its only 20AMP? If Im bring in a potential 4Kw at 240V on 2.5mm flex should I not have a 32amp relay? And does anyone know where I can get one?

[AndrewIC]

Huge range of relays and contactors at RS, I'd be very surprised if they didn't have something suitable.

 

If I was starting again with the shoreline wiring, I think I would put in a power inlet at each end of the boat and auto-switch between them with a relay, but otherwise I'd go for simplicity and the fewest number of moving parts every time!

[Tony Brooks]

Hi

Just taken possession of 39ft wide beam Broads Cruiser and a CRT mooring on the River Lee with no shoreline. Along with many other tasks I need to re do the AC system to run of an inverter and Generator and like the look of the circuit diagram here My link the one with a 4 pole change over relay.

 

System set up so far : Generator 5KW kipor deisel 240v ac to be run every other day or so to charge up the batteries and do the laundry/vacuum the boat etc. I've got 300 AHrs of 12v sealed Lead acid battery, a 40Amp Mastervolt charger and 2000 W pure sine wave inverter again from Mastervolt.

 

So you can see I've just about run out of money and don't want to buy 2 RCD/MCB units (space and money) so I like the look of the 4 pole switching circuit discribed on smartgauge the automatic one with a relay rather than a switch. My question is where can I get one and what am i looking for. I've been looking for a 14pin 4PDT Power relay 240V 32A, is this what Im after? Could I use 2 x 2PDT power relay? The nearest I've found is thisMy link but its only 20AMP? If Im bring in a potential 4Kw at 240V on 2.5mm flex should I not have a 32amp relay? And does anyone know where I can get one?

 

 

Why 32 amps? kW = 16 to 18 amps so 20 amps from a reputable UK supplier should be fine.

 

If cash is the main problem then get 2 x 13 amp sockets and one plug. Mount sockets somewhere dry and protected. Wire one to the inverter and one to the generator input. Wire RCD to 13 amp plug with short length of flex. Now you have a fail safe manual change over. Just plug into whichever socket is the source.

 

Please note that the wiring , plug and sockets between sources and RCD are no protected. Also note the fuse in the plug will limit the input to 13 amps instead of 16 amps but unless you are running a full electric cooker I can not see that is a problem.

[AndrewIC]

5kW is around 20A. I wouldn't put that through a 13A plug...

[by'eck]

Kraus and Naimer are a popular choice. They supply off the shelf and custom made wafer switches including the four pole three way AC switch used on my last boat.

 

 

Their full catalogue can be downloaded here

[jonathanA]

You could modify Tony's suggestion and use a 16A plug with 16A sockets, but your almost as easy to provide a manual changeover switch and thats much better imho.

 

The other option is that you don't actually need a 4 pole relay, you could use a 3 pole relay which might be easier to get hold of (possibly - haven't looked myself). You don't really need to switch the neutral for the 'non inverter loads' as well as the live. It is worth making sure that you can't accidentally leave the charger running off the inverter for instance so a 3 or 4 pole changeover switch or relay makes sense.

 

finally 2.5mm flex is only rated at 20A not 32A

[David Schweizer]

If you want the one recommended on the Smartguage site, this is where you can get them from :- http://www.thetoolboxshop.com/albright-sw180-series-single-acting-solenoid-contactors-410-c.asp

 

They are not cheap, but they are very substantially built. I would not waste time trawling the internet for a better price, as far as I know Toolbox are the sole importers.

Edited December 28, 2012 by David Schweizer

[MikeV]

The nearest I've found is thisMy link but its only 20AMP? If Im bring in a potential 4Kw at 240V on 2.5mm flex should I not have a 32amp relay? And does anyone know where I can get one?

The relay you link to only has a 24V coil whereas you need 240V. If you can find a suitable relay make sure it is break-before-make. Inverters don't like being connected to another mains source.

 

There are of course more sophisticated (and expensive) solutions such as the Sterling Autoswitch which ensures that the generator output is stable before switching and that there is a definite break before the next source is applied. Personally, at this stage, I'd go with a simple manual solution and look to do something clever later.

[Tony Brooks]

5kW is around 20A. I wouldn't put that through a 13A plug...

 

 

Agreed, but he says "a potential 4Kw on 2.5mm flex", not 5 Kw although that is what he says his generator is. In any case he will not be passing 20 amps through a 13 amp plug because the fuse will blow - eventually, but before serious heat damage to the plug/socket.

 

I am still trying to work out where he gets that loading from on a boat unless he is cooking on electric and just hope he does not try it from a shoreline at some time.

[smileypete]

Try this thread:

 

http://www.canalworld.net/forums/index.php?showtopic=32023

 

cheers, Pete.

~smpt~

[jonathanA]

As Mike v says you need a relay with a 240V AC coil. not the 24v one you linked to or the subsequent 12 v relays posted by others.

 

something like this :

 

http://www.ebay.co.uk/itm/RE04-FINDER-16-AMP-240-VOLT-DPCO-POWER-RELAY-16a-240v-62-82-8-230-0000-/221169658480?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item337ebd2a70

 

although this is only 2 poles so wouldn't give you idiot proof disconnection of non inverter loads (e.g charger) - would get you going though

 

 

ETA- I think I'd use a manual changeover for a generator supply so that you had chance for the genny to sort it self out before putting it under load.

Edited December 28, 2012 by jonathanA

[GUMPY]

I use one of these

http://uk.rs-online.com/web/p/non-latching-relays/0376903/

To switch between shore and genset its wired with the coil on the shorepower feed so that as soon as its live the genset is disconnected.

[Phoenix_V]

If you want the one recommended on the Smartguage site, this is where you can get them from :- http://www.thetoolboxshop.com/albright-sw180-series-single-acting-solenoid-contactors-410-c.asp

 

They are not cheap, but they are very substantially built. I would not waste time trawling the internet for a better price, as far as I know Toolbox are the sole importers.

Albright are a UK company Albrightinternational dot com, and you can buy direct, but as far as I know they only make dc operated units.

[tangledfooted]

Thanks for all the advice. I think i might go for a manual 4 pole switch as suggested above. I think 20 Amps is the max out put from the genset anyway and we are unlikely to use more than that even with my partners curlers/hair dryer and washing machine. I just wanted everything fool proof as she doesn't get on with technology. I can see her starting the generator but not switching over or something. Anyway, Ill check out the links suggested. thanks.