Author Topic: Rich Electric Co Ltd 6kw 24v pure sine inverter problems  (Read 757 times)

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Offline frackers

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Rich Electric Co Ltd 6kw 24v pure sine inverter problems
« on: April 22, 2016, 11:02:04 PM »
Greetings all

I've just received one of these to look at to puzzle out the fan running all the time and intermittently dropping out before usual low voltage shutdown.

Seems to be well constructed, I would guess getting on for 30kg of toroid transformer with 8 parallel windings for the primary with 20 off irf3205 MOSFETs in each of the 4 H bridge legs. Its at least 6 years old having been bought about 5 years ago as an end of line - they only do 48v at this power now it seems! Two 300A fuses in parallel indicate the current capabilities!

Does anyone have any details - I can't find a model number on it. I'll break it down enough to get PCB numbers etc in the next day or two but I need to get into it as my mate is running a dodgy mod-sine backup at present.

I plan to start with a strip down and clean-up as it seems to be full of moth remains!! That might improve matters but I would guess there is a temperature sensor reporting incorrectly for the fan to run and to shut down when it shouldn't. The sensors (5 I've counted so far) all 2 wire so I guess they are straightforward RTDs

Does anyone recommend what else to check?


Robin Down Under (or are you Up Over!)

Offline rossw

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Re: Rich Electric Co Ltd 6kw 24v pure sine inverter problems
« Reply #1 on: April 22, 2016, 11:39:03 PM »
8 parallel windings for the primary with 20 off irf3205 MOSFETs in each of the 4 H bridge legs.

Will all the home-wound transformers of late, that actually makes a very interesting thought - at least, in my mind it does - but possibly completely out of my tree...

Lots of us have fairly low "base-load" requirements, in my case around 300-500 watts. In come cases I hear people getting by on 30-50 or so.

Yet, we all need support of many kW for starting motors, running the kettle, etc...

Inverters don't seem to do one end without compromise at the other.

Has anyone thought about multiple primary windings, but using smarts in the software (or driver hardware) that will only drive as many "primaries" as required for the current load? Virtually no "standby power" running a huge brute of a primary winding when you only need 50W out... be much easier to wind 8 smaller primaries each of say, 8 sq mm, than one of 64 sq mm!

Or am I being silly??

Offline frackers

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Re: Rich Electric Co Ltd 6kw 24v pure sine inverter problems
« Reply #2 on: April 25, 2016, 04:08:35 AM »
I've found more info about this inverter - it helps if you read the label on the case before you take it off and put it to one side!!

http://www.powermaster.com.tw/PM-6000L.htm

Even the pictures look right!!

I think I may have 'fixed' it as I've cleaned it up, jiggled all the connectors and now the fan starts at power-up and then stops once the inverter has come up to all green lights.

I'll get Shawn to re-install it and see how it flies...
Robin Down Under (or are you Up Over!)

Offline oztules

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Re: Rich Electric Co Ltd 6kw 24v pure sine inverter problems
« Reply #3 on: April 25, 2016, 07:45:53 AM »
Rossw, magnetising current is magnetising current... no ,matter how you drive the core, the result will be the same if the primaries are the same and are to be parallel for high power... no difference.

If they are tapped for the primary, then you could use the tap with the most turns to get the amps down and the turns up for the same magnetising effect...... but then you have other problems with the head room.... seems more trouble than it is worth really.

Only by using smaller cores for the small power, and larger cores for larger power can you get any real relief.

I think Schnieder do this with three transformers of differing size from what Chris Olson was saying when he got them... but they are EI types so their efficiency is poor anyway you do it. Also their weight is not much different to mine.... and their transformer would have to be twice the weight of mine to compete with the torroid.... so they are under powered anyway compared to a torroid of similar weight.

The little one I am running at the moment has less than 30 watts idle, and can pull 9kw starts... thats fine by me... with more turns to both the primary and secondary, that can come down further too.


Or, put another way.......

If you have to worry about 30 watts, then you have more problems than just the idle current, and thats the least of the problems to be faced.

It is hard to get excited about .7 of a Kwh really...

...........oztules

Flinders Island...... Australia

Offline Pete

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Re: Rich Electric Co Ltd 6kw 24v pure sine inverter problems
« Reply #4 on: June 14, 2016, 03:33:00 AM »
Hi Rossw, I just use two different inverters to run my place. I have a 600 watt sinewave that runs most of my stuff. eg. Washing machine, charging laptops, stereo etc. Then for things like power tools and toasters I use a Powerstar W7. I have added an inductor (thanks for Oztules) in series with the transformer primary that reduces idle current from 8 amps down to 3.8 amps ( my system is 12 volt).
I just have a changeover switch to change from the small efficient inverter to the powerstar.
I put myself in the bear of little brain school, I keep my system and lean and simple as possible.
I also have a Powerstar W7 running the shed, but that is only turned on when I need 240 volt power. All my lighting is 12 volt.
Have worked as an Electrician and Electronics Technician most of my life and I don't trust electronics enough to want to run my lights off them.  It also seems like a waste of power when these days 12 volt led bars are great lights at minimal power consumption.