Inverter or Relay (oh woe is me) (1 Viewer)

[Duck Truck]

Background
We were away and were running our inverter to provide 220v
Then the inverter clunked off (the relay which switches between external 220v supply and
inverter 220v supply always clunks as it's mounted on a bulkhead wall that ampifies the sound)
Result No voltage from the inverter.

Check 1
However If I plug in the supply lead from an external mains source via the external socket we get 220v all round as normal.
Checking with a volt alert stick it bleeps and flashes ok when held against the power cable right the way to the relay and relay output

I THEN UNPLUGGED THE EXTERNAL SUPPLY

Check 2
The voltage from the inverter goes via a 13amp plug and cable on the side of the inverter to the relay
I have checked the fuse on the plug that's fine.
However when I hold the volt alert stick next to the output cable no bleep no light.
I thought aha ha the inverter is stuffed.

Check 3
I unplugged the output plug and cable.

I then plugged in a normal extension lead and switched the inverter on
the extension light led lit up so I plugged in a hairdryer and that ran
and heated up and blew hot air.

HOWEVER
When I hold the volt alert stick anywhere on the extension cable and hairdryer cable
IT SHOWS NO VOLTAGE NO BLEEP NO FLASH

I INSERTED MY AVO INTO THE SOCKET AND CANNOT DETECT A VOLTAGE
HOWEVER

WHY DOESN'T VOLTAGE FROM THE INVERTER SHOW UP

HELP

 

[Duck Truck]

sorry!!
so fuddled I forgot to say thanks for reading this

 

[Stealaway]

My first thought is low voltage to inverter due to flat batteries - especially at this time of year

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[Figaro]

Batteries dead ?
What's a volt stick ? Have you got a multimeter

 

[Richard n Ann]

Is it a pure sine wave inverter? The non sine wave ones don't show as high a voltage on a meter because it's a square wave signal and meters are made to read RMS ac.

Last time I measured one it showed a voltage of around 150vac
AVOs are ancient and might not show anything.

 

[Duck Truck]

Hi thanks everyone
We have four 12v GEL batteries.
They seem absolutely fine
The inverter fan kicks in and the inverter runs a hairdryer at full heat

Richard
It's not a pure sign wave so i guess thats why the voltage doesn't show
That information was very very helpful
How can i then test the voltage output please
Kev

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[Richard n Ann]

Use a digital multimeter set on AC volts, whatever it reads when it's on is the normal reading. The LED will tell you if it's on anyway.

 

[Pausim]

I have a recollection that some inverters have neutral earth bonding and some are centre tapped. I am no expert but think that in the centre tapped versions there is no real live and neutral, both in effect being live, but only carrying 125v. When the electricity reaches the appliance the effect is 230v because they are out of phase but during transit they are individually lower and safer voltages, which might not show up on your volt alert stick. Perhaps being out of phase has something to do with it as well. I remember finding the explanation in the instructions of a Sterling inverter which I no longer use. I think they recommended the centre tap as being safer where there was no rcd because of the lower voltages.

 

[Richard n Ann]

Yes of course, if you measured between earth and one of the lives you would get sod all because the earth on most (if not all new inverters) is floating, ie not connected to anything.
If you measure across the outputs (they are both lives) you should get about 150v on a modified sine wave inverter.
The voltstick won't show anything either, your hand isn't earthing it because the inverter isn't earthed.

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[Duck Truck]

Thanks everyone
really helpful
i understand what is being said
I think I need to get a new multimeter as well.

My guess is the relay has gone down
because the inverter is running the hair dryer when the power supply
doesn't go through the relay

will keep everyone informed
and thanks again to everyone who replied
much appreciated
Kev

 

[eddie]

The relay has a Normally Open and a Normally Close (N/O & N/C) input/output

I suspect that the mains supply is on the N/C contacts which is why it works fine, and the inverter is on the N/O so needs the relay energised to switch across, which isn't happening

If you have a picture of the relay we should be able to tell you how to swap the supplies to test this theory

 

[Deleted member 57092]

The 1200w inverter on our boat packed up and before buying a new one I decided to take it apart.
There are six blade fuses on the circuit board inside it, no mention of that in the handbook and a ‘no user servicable parts inside ‘sticker on the casing.
Worth a look ?!

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[Duck Truck]

Hi Paul yes I checked all the blade fuses inside
All OK

I will post some pics
Eddie thanks again to everyone

 

[Bartyfixedit]

The volt stick is reliant on the supply having some relation to "Ground" . Mains AC is grounded, hence the stick will usually detect it. The inverter output may well not be grounded in which case the stick will not detect it.
There is a reason why voltage detection sticks are not permitted in professional use, they give too many false negatives.

 

[Duck Truck]

still waiting for the relay to be delivered

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