Switching. Another newbie question

[Krusty]

Once again can you help me please.

Equipment: Travel Power, rotary switch, inverter.

Problem: When running the engine, the Travel Power supplies all the sockets with 240 volts.

Then I stop the engine, turn the rotary switch to the inverter mark

and the inverter supplies the 240 volts to the sockets.

My problem is I often forget to turn the switch back to the TP mark, hence running

for an hour or two with the inverter draining the power from the batteries unnecessarily.

Question: Is there some clever wiring I can do or fitting a switch/device that will do the

change over automatically?

Many thanks K.Rusty

[bottle]

Cheapest way of doing it :

 

Place a sign next to the engine start key.

 

 

 

There are auto switches etc. but I am not qualified to recommend one etc.

[Phil Ambrose]

Check to see if your inverter is a UPS model (Uninterrupted Power Supply) if so just needs wiring in. I say this because my inverter is a UPS model but I use it so rarely I didn't bother.

 

Phil

[bottle]

err!

 

I think his problem is the opposite of the UPS function.

[Pete & Helen]

What about the "Travel Power" (which I assuming is just a 240v alternator) powering a relay that does the same job as the switch. But you will have to consider the current that the contacts will have to take and make before break contacts to prevent arcing across them, no recommendations on the relay type just a suggestion on how you could solve your problem. I would also add some sort of indication so you can see where the power is been drawn from

[Chalky]

I have a land line and an inverter. I have a contactor that can switch between the two to supply the sockets on the boat. The coil of the contactor is powered off the land line. When the coil is off the inverter is connected to the sockets. When the land line is connected the coil is powered, closes the contactor and connects the land line to the sockets. There's a neon (warning light) connected across the coil to show the status. It's a crude solution however it works ok and means I can't forget to change over.

[Pete & Helen]

I have a land line and an inverter. I have a contactor that can switch between the two to supply the sockets on the boat. The coil of the contactor is powered off the land line. When the coil is off the inverter is connected to the sockets. When the land line is connected the coil is powered, closes the contactor and connects the land line to the sockets. There's a neon (warning light) connected across the coil to show the status. It's a crude solution however it works ok and means I can't forget to change over.

Same Idea, so at least it shows my theory is ok

[Paul C]

The easiest way is to redesign the circuit so that no high-power (or high consumption) mains electrical items are able to use the inverter. This way then it doesn't matter if you inadvertently forget to switch to and from, and it also means you retain the flexibility of a manual switch to choose eg inverter even when the engine is running, if you wanted to (and its less complex). There's a bunch of suitable diagrams on the Smartgauge website somewhere.

 

Auto changeover switches are available though.

[Sir Nibble]

I have a land line and an inverter. I have a contactor that can switch between the two to supply the sockets on the boat. The coil of the contactor is powered off the land line. When the coil is off the inverter is connected to the sockets. When the land line is connected the coil is powered, closes the contactor and connects the land line to the sockets. There's a neon (warning light) connected across the coil to show the status. It's a crude solution however it works ok and means I can't forget to change over.

That's the way to do it. A motor starter contactor would be a good cost effective relay.

[Nightwatch]

Cheapest way of doing it :

 

Place a sign next to the engine start key.

 

 

 

There are auto switches etc. but I am not qualified to recommend one etc.

This is what I would do!

[Grace and Favour]

Cheapest way of doing it :

 

Place a sign next to the engine start key.

 

 

 

There are auto switches etc. but I am not qualified to recommend one etc.

This IS what I do!

[Phil Ambrose]

err!

 

I think his problem is the opposite of the UPS function.

Surely in UPS mode when Travelpower switches off the UPS function will automaticly bring the inverter on-line and conversly when the Travelpower kicks in the UPS function will revert to drawing 240v from said travelpower.

 

Phil

[Krusty]

Cheapest way of doing it :

 

Place a sign next to the engine start key.

 

 

 

There are auto switches etc. but I am not qualified to recommend one etc.

 

Thanks but I tried that and still would forget sometimes.

Got so used to seeing the sign there.

What about the "Travel Power" (which I assuming is just a 240v alternator) powering a relay that does the same job as the switch. But you will have to consider the current that the contacts will have to take and make before break contacts to prevent arcing across them, no recommendations on the relay type just a suggestion on how you could solve your problem. I would also add some sort of indication so you can see where the power is been drawn from

 

 

Thanks P and H. Sounds like a good idea.......I'll give it some thought..........If I remember.

The easiest way is to redesign the circuit so that no high-power (or high consumption) mains electrical items are able to use the inverter. This way then it doesn't matter if you inadvertently forget to switch to and from, and it also means you retain the flexibility of a manual switch to choose eg inverter even when the engine is running, if you wanted to (and its less complex). There's a bunch of suitable diagrams on the Smartgauge website somewhere.

 

Auto changeover switches are available though.

 

 

Thanks Paul. Just looked on inter-web and Sterling do one but want 330 of my pounds.

I'll have a look at some other sites now I know what to look for.

[nicknorman]

Yes you can get auto-switchover relays. Although you can make one out of a mains rated multipole relay, the pukka ones include some time delay to ensure the supply is stable before switching over. This is probably not that important for a TP that starts cleanly, but more important for a shore power socket which might not be connected cleanly.

 

Be sure to switch both live and neutral. The inverter will be (should be) neutral-earth bonded, whereas the TravelPower has a centre tapped voltage, ie each line is +- 120v about earth, so there isn't a live and neutral. If you connect all the neutrals together you will blow up the TravelPower. Obviously you also need a break before make relay but they are pretty much all like that.

[Richard10002]

Hang your keys on the inverter switch, or very close to it. When you want to start the engine, you will always be reminded to turn the inverter off.

 

On a raw water cooled engine, I always hung my keys on the seacock, so I couldn't start the engine without remembering to open the raw water inlet.

[Pete & Helen]

Found this from another thread which gives you options. http://www.smartgauge.co.uk/nb_ac_sys.html (look about half way down)

It also says that I was wrong to suggest make before break contacts as this can apparently damage your inverter, We live and learn. Which is one of the advantages of this forum.

 

Have you a link that describes the "Travel Power" as I still haven't got it fully clear in my mind the operation of this unit yet. Ta

[jonathanA]

That's the way to do it. A motor starter contactor would be a good cost effective relay.

 

i'm not sure I'd trust a starter motor contactor to switch mains and most are single pole anyway (if not bult into the starter these days)

[Krusty]

Found this from another thread which gives you options. http://www.smartgauge.co.uk/nb_ac_sys.html (look about half way down)

It also says that I was wrong to suggest make before break contacts as this can apparently damage your inverter, We live and learn. Which is one of the advantages of this forum.

 

Have you a link that describes the "Travel Power" as I still haven't got it fully clear in my mind the operation of this unit yet. Ta

 

Hi P and H.

Thanks for the link, I'll have a look see.

TP? No link I'm afraid.

Basically it's an engine driven ( by belt ) 240 volt generator/alternator via a box of clever tricks.

[Iain_S]

 

i'm not sure I'd trust a starter motor contactor to switch mains and most are single pole anyway (if not bult into the starter these days)

 

I think Sir Nibble was thinking of switching the inverter input.

 

Iain

[smileypete]

 

Once again can you help me please.

Equipment: Travel Power, rotary switch, inverter.

Problem: When running the engine, the Travel Power supplies all the sockets with 240 volts.

Then I stop the engine, turn the rotary switch to the inverter mark

and the inverter supplies the 240 volts to the sockets.

My problem is I often forget to turn the switch back to the TP mark, hence running

for an hour or two with the inverter draining the power from the batteries unnecessarily.

Question: Is there some clever wiring I can do or fitting a switch/device that will do the

change over automatically?

Many thanks K.Rusty

 

 

How is the inverter normally switched on or off?

 

cheers, Pete.

~smpt~

[jonathanA]

 

I think Sir Nibble was thinking of switching the inverter input.

 

Iain

 

very few inverters like having their output connected to another 240 v source, so unless it one of those there'd be a danger of a blue flash and puff of smoke incident followed by trip to the chandler for a new inverter....

[Krusty]

 

How is the inverter normally switched on or off?

 

cheers, Pete.

~smpt~

 

Once I've turned the rotary switch to the inverter position it's then turned on via a remote switch.

[Kae]

The Smartgauge website already linked to has several 240v 4 pole relay schematics showing exactly what you want to achieve. Personally I prefer a manual switch as we're liveaboards and I like to know for definite which power source we're using, but that's personal preference.

 

I know exactly what you mean though, I have manual calorifier isolating valves and occasionally I forget to open them when we set off and I wonder why we have no hot water!

[Richard10002]

The Smartgauge website already linked to has several 240v 4 pole relay schematics showing exactly what you want to achieve. Personally I prefer a manual switch as we're liveaboards and I like to know for definite which power source we're using, but that's personal preference.

 

I know exactly what you mean though, I have manual calorifier isolating valves and occasionally I forget to open them when we set off and I wonder why we have no hot water!

Hang your engine key on/near the isolating valve - hard to see how you could ever forget thereafter? Hanging keys somewhere is free and simple. If you include it in your briefing for new crew, it will be ingrained for everyone.

[smileypete]

 

Once I've turned the rotary switch to the inverter position it's then turned on via a remote switch.

 

OK, just a suggestion if you don't want to fiddle with the mains side of things....

 

Get a bog standard 12v car changeover relay, wire the contacts in the inverter remote circuit. Then wire the coil to the engine ignition switch. That way when the engine ignition is on it'll switch in and disable the inverter.

 

Also best fuse the the wire that supplies the relay coil with a small fuse near the ignition switch, that way it'll protect it from any short circuit type fault.

 

cheers, Pete.

~smpt~