Reversing neutral/active automatically

[supersparky]

And a pot plant..... good on ya. that would have paid for a few nights.

Do you reckon that he meant,maybe a flower pot?


What I was trying to highlight in my posts last night was the danger to others with reversed polarity in the power tower at the CP's.
You might be clever enough to detect and overcome with a device that probably shouldn't be used, but the next poor sucker that comes along might not be so lucky. The best approach would be to report it to the CP operators so it can be repaired correctly.
And if they aren't too happy about what you tell them then report it to the relevant supply authority. They will make sure that it gets sorted quickly.

[homeless]

Actually a pot of herbs.




You naughty people it was parsley now go and hang you heads in shame.

[jon_d]

I think I met Herb once.
I wonder if it was the same bloke.

[BruceS]

Probably was Jon! Can you remember what happened in the following 12 hours after you 'met' him?
Heard one chap turned into a tutu dancer once he met Herb too......

[T1 Terry]

I wrote a long post yesterday and it seems to have vaporised into the ether. I'll try again.
The best solution is to use an inverter with sufficient power output to cover you needs. The next level is an inverter that can cover all your needs plus auto switch between battery and mains supply. This type of inverter will test the quality of the supply to determine if the polarity is correct and it is a clean pure sine wave supply at the correct voltage. Once these criteria are met, it will open the earth neutral link and then switch to mains power. These newer type inverters have their own built in RCD so the house supply is always protected.
To keep the battery charged if the mains power isn't clean enough for the inverter to accept, wire a power point into the mains supply side of the inverter and use a battery charger that is either dumb enough not to care what the input is, or smart enough to be able to operate on a wide range of frequencies and voltages and doesn't have a problem with the polarity being reversed.
Now all bases are covered and you will know the power supply inside the RV is of a good quality and safe to use.

These newer inverters with the auto switching earth/neutral link remove the need for an RVD to be added to the supply and the need for a 3 way make before break 240vac supply switch.

T1 Terry

[Grandad]

Thank you everyone for your help in this matter.
I’ve put this project in the ‘Too Hard’ basket for now. I combined both schematic diagrams into one so I could get a better idea and as soon as I did a glaring problem jumped out and bit me.

The relay relies on a reversed negative to power itself and trip the contacts, but as soon as they’re tripped the negative power disappears, so the contacts would open so the negative power is available again to close them, which would power the relay to open them and so on indefinitely or until the contacts burnt out. Meanwhile there would be a lovely clicking sound before the smoke would no doubt escape. .

I know there are such things as a locking relay which will lock into position once activated so I went looking for more info. After several hours of reading stuff I really didn’t understand I gave up. This is above my paygrade and the benefit is not enough to pay my sparky $80 an hour to work it out for me.

Terry, I didn’t know there were inverters that would do this. Good to know. When I looked at inverters that would automatically switch between battery and mains I found them hellishingly more expensive. To the point where I decided a three position changeover switch is far easier on the wallet.
Is it safe to assume the inverters you speak of may be the same? Do you have a brand I can look at?

It’s probably time for you and I to decide exactly what my needs will be. I now know pretty much what I will want to power. How many lights, fridge, microwave etc. So I have enough info for you to advise me how many A/H cells I need, how much solar, what size and kind of inverter etc.

Would you like this discussion via email or is here ok with you?

I’ve also realized none of you here have any idea of what I’m building so I thought I might put together a build thread in the hope that some of you may find it interesting.

[T1 Terry]

Our most popular used is the Projecta IP2000. It has a built in RCD, auto switching to external 240vac supply if the power is clean, can power a microwave, roof top rattler, coffee machine, most kettles, most induction cooktops and of course, the Phillips Airfryer, an absolute must as it replaces the need for an oven, but only one of these appliances at a time.
Next would be the PIP2440, but only suits a 24v system and don't have the built in RCD. Can do all of the above, plus can become a battery charger and includes an MPPT solar controller, will deliver 5kva (4,000w) continuous and double that for a few secs (unlike the ebay cheap stuff that can supply that peak power for milliseconds, useless for anything) These units can also be ganged together to multiply the available max output and multiply the battery charging ability if required.
The W7 type inverter chargers do not have an RCD and really a bit too heavy on the standby requirements to be left on 24/7, really only suited to switching on when required.
Then there are the Victron range, pricey but a great piece of gear. Then the Mastervolt range, again pricey, but quality, Aust made and fully supported by the company who can do a full overhaul even on a 20yr old unit and bring it back to new specs.
There is also the Rich Electric range, I've never installed one so all the info is second hand from Busman. These were sold through Jaycar but they pulled out of being a reseller for what ever reason.

T1 Terry

[Busman]

For my money the best of the lot, pity the designer pulled the plug on working 18 hours a day for Jaycar. Thought seriously about importing the range when we sold the farm but decided we didn't need another business so moved to Stanthorpe instead. Have learned lots about winemaking, pressing our second lot of Cab Sav this morning. Amazing difference in the 2 styles, all determined by fermentation temperature. Should have the younger style ready to drink by the end of the year.