Running a washing machine from an inverter

[Steve]

but if the freezer kicks in then it strains for a second then trips, i'm sure the freezer isn't rated at 1000w+

The lights dim in our house when the fridgefreezer comes on. The compressor has a large inrush current, which would appear to be the issue in your case, and the OP's. For a second or so on startup, the compressor will draw upwards of 20 amps, despite only being rated at about 200 watts. This short duration high impulse is not enough to trip a 16 amp MCB or blow a 13A fuse, but it may well cause problems with more sensitive supply equipment such as invertors and small generators.

 

[ericmark]

The inverter modified sine wave is rated at 3KVA with 6KVA peak for motor starting etc.

hi eric
modified sine wave inverter's are no good for washing machines your inverter needs to be pure sine wave
have a google

Matt

We were aware that many machines will not work on modified sine wave and I wrote and phoned most manufactures before buying and LG were the only one to say "They could see no reason why it would not run" they did not say it would run. However since it will run on Cold and Steam cycle with no problems it would seem very likely that the problem is batteries not big enough.

I have been told it is not a straight line graph load to voltage on leisure batteries and that at a critical point voltage drops very quick.
Unfortunately my son was unable to test last night but the 2Kw kettle test rather than 1.6Kw will be of interest also the jump lead and adding a extra battery.

As to fridge/freezer unlike the washing machine motors these do not have an inverter soft start and will likely take 10x rated value to start so for a 250W motor one would need an inverter with 2500W peak. The inverter we have is rated 3000W continuous and 6000W peak however many show their peak value as rating rather than continuous and many so called 3000W inverters are only 1500W continuous also of course the inverter built into the washing machine motor does not really mind if fed AC, DC or sine or square wave as all is turned into DC before feeding motor anyway. But feeding modified sine wave to a motor must produce some harmonics and without an oscilloscope it is near impossible to monitor the harmonics.

I am crossing my fingers and hoping it is just too much load for batteries and more batteries will cure the problem.

 

[ericmark]

Inverter after burnout

• ericmark
• 2 Jul 2010
• 1

Inside 3000w inverter after it failed

Clearly a fault with inverter. It had been on light load for some time running battery charger for some tool batteries and suddenly stopped this was what was seen when we checked the fuses.

I thought it may have been faulty inverter but did not expect this. Odd seems control cables not the main components that have failed.

Under Guarantee but note web site has gone so maybe company has gone?

 

[Monkeh]

You let the mysterious blue smoke out!

 

[ericmark]

Good news the supplier has agreed to repair but we need to pay postage however they claim due to overload but it is a 3Kw inverter with 6Kw surge capacity and largest item was a 2.2Kw washing machine with an inverter driven motor so soft start and as yet no idea why it should have failed?

 

[ericmark]

Update:- It cost £100.20 to return the inverter in postal and customs charges sure the returned item is new and not old one repaired.
On reconnecting we tried again to run the washing machine and it did run but after the heater cut in monitored at 9.4 amp and it was running with this load for about 4 minutes I started to smell something burning. It was turned off and on re-test everything seemed OK. However as a result we have considered although rated at 3000W continuous and 6000W for 5 minutes really it is only able to deliver 1500W not the 2200W of the washing machine.
Since the inverter is on return able to run washing machine we think it was damaged earlier when boiling kettle. We had smelt the burning smell with last inverter when boiling kettle and had considered it was due to a battery isolator switch which failed.

 

[TicklyT]

It's a pity you have to use an inverter for, basically a resistive load like an immersion heater or kettle, but I suppose the wiring for a 12 V 2KW immersion heater would be something else.....

Two birds with one stone...... A water-cooled inverter? :

 

[ericmark]

He has an ample supply of hot water. The problem is washing machines need to heat the water after the wash has started so blood and egg etc. are washed out before the hot water can set the stains. All washing machines now are as a result cold fill. The hot and cold fill machines are things of the past.
I have written to the manufacture complaining as the so called 3000W inverter is not able to produce 3000W. I await their reply.

 

[ban-all-sheds]

However as a result we have considered although rated at 3000W continuous and 6000W for 5 minutes really it is only able to deliver 1500W not the 2200W of the washing machine.

Should be easy enough to load up the inverter with something uncontroversial, like a 3-bar electric fire.

I have written to the manufacture complaining as the so called 3000W inverter is not able to produce 3000W. I await their reply.

See if you can get 3kW of near-as-dammit unity power factor load, e.g. radiant heaters, fire it up, and let it run.

On camera.

If what you've reported is correct, it won't be long before the inverter shows visible signs of distress...

 

[ericmark]

Thank you for your thoughts. We have been given permission to open the inverter to test it. There is an array of FET's and car type 16A fuses one for each FET and it seems one FET may have failed and blow the fuse and the others would continue to work.

However once that has happened the there is a chance of overheating since the safety devices are set for when all FET's are working.

The first time it went it was after plugging in a kettle i.e. pure resistive load but at the time we did not realise anything had blown. Hind sight is good and we now realise that's why it would not run the washing machine when fitted because some of the fuses had already blown. However at the time we though the fault was the battery isolator and did not realise the inverter had been damaged.

If we could return the inverter to a shop it would be easy but the last time it was returned it cost two thirds the new price of the inverter so we must consider very carefully if returning the inverter is worth while or are we just wasting money.

 

[SteNova]

so really it needs to turn off as soon as one fuse blows

 

[electronicsuk]

Sounds like a poor quality inverter, might be worth investing in something tried and tested like a Xantrex.

 

[Monkeh]

Frankly that looks a little.. well, shall we say pathetically small for 3kW? Doesn't look much bigger than my 150W inverter, and if those little metal places are all the heatsink it has..

 

[flameport]

With the problems you have had with the inverter, it could be time to cut your losses and get another inverter which is actually up to the job.
The one you have clearly has major problems and even if it can be made to work, how long before it fails again?

Xantrex mentioned already, or Victron Energy.

Obviously not cheap options, but then neither is paying out 100s every time the existing one melts.

 

[ban-all-sheds]

I would have thought that if you can show that it won't supply a steady-state load of 3kW indefinitely that you've got excellent grounds for a full refund of all purchase, repair and shipping costs.