guess who bought a power jack inverter

[oztules]

Sounds like your switching the mains after the inverter... this is fine, and it will carry any reasonable load on start up... I have hit mine with 8kw loads or more on turn on....no problems

It is driving the ac input to the inverter that is the problem. It syncs in fine ( although they still say to turn off, I don't think it is necesary, as it gently ramps over.... but it is turning off the mains to the inverter ( acting as charger at that point) that dices with death. It is instantly goes to 50hz, which depending where on the curve it is, will determine the surge current into the transformer.... it may also be that your single transformer is not big enough to cause the fault.... mine is huge, so kills it very effectively.

This is taken from ebay advert for the 3kw unit

PLEASE NOTE: for battery charge mode: before charge the battery, please turn off the inverter first, connect the AC power cord with home AC source and inverter, then turn on the inverter to start the function. When finished, need to turn off inverter first, then disconnect the AC power cord. Otherwise the PCB board might be damage due to high voltage spark.

Interestingly they also claim it is a UPS unit....go figure.

Your taiwan kipoint inverter may not use torroids (judging from the low efficiency I think this is the case (80%))... and non-torroids do not have the surge of torroids... can be 60 times the run current. The electronics was designed for EI transformers from the W7 style of inverter, and they have no problem.. even with two huge transformers in them./... torroids are a class of their own.... they are very tight magnetically. If they actually had control of the software, they could simply slowly move back to default frequency, and the big problem would be solved.... but I don't think they have control of the software in the chip for many functions.

They are putting in ferrites now, and I believe that has solved the original problem.... have not bought a new one  for years now ( yes they still are running fine)


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

[augustus]

Is the label on the transformer blacked out in pen?

The 8000W unit should have two transformers.

The 6000W unit had two 3000W transformers.

The variants of transformers used to be 3000W for the 3000, 6000 and 10000W units and 5000W for the 5000, 8000 and 15000W units.

If you bought yours on an auction that had a low price start . . . . .
Hi OTW sorry for the tardy reply, christmas and renovations and all that got in the way! my inverter was a buy it now with full 8000w labeling, and I looked at the spec and weighed it and it was the 22kg as specified!
I'm of to the shack tomorrow so I will check the labeling on the toroidal trannie and report back!
merry christmas if Applicable
aug

I only buy units either for me or for people who come to me through Cher. I pay more usually than ebay prices.

Best wishes

OTW

[toxsickcity]

well quoted 850au for a 1200 kipoint lf wow
looks like ill go pj...

i perfer to use high efficient delta with active pfc to charge my batteries...

i wont be feeding any sort of input 240v to my inverter
i try go simple for my setup...

good news you said about difference between what i thought and what is!

i will get my inverter after new year.. early tho... i will be back with my findings...

edit: kipoint trans is round.. terroidal?

i have seen old and new seems to have many additional bits

the email girl sent me a doc manual for new

[off the wall]

Hi!

Earlier in this thread I detailed the circuit diagram for a changeover box to switch between inverter and mains in a manner that doesn't create great voltage jumps with independant phases. Perhaps that idea might be useful in the changeover function. . . .

By using two relays which interlock so that the one cannot be energised before the other is released, and being energised on AC cannot connect until energised significantly towards the peak of the next half cycle. Whether the result is connection at the zero point I haven't measured but most certainly the equipment connected on the switched circuit seems to demonstrate no knowledge of having suffered a changeover.

Whether this would assist on the battery charging issue I've no idea - I use my unit only as an inverter.

Best wishes

OTW

[toxsickcity]

i also intend to use my inverter as inverter mode only..

my switch has not taken into account phase and cycle time.
its a simple dual terminal wired to the power board, and inverter on 1st set, mains 2nd set.

i have accidentally hammered the relay connecting it to a circit no electrical issues either.. my thaughts are caps take care of any time gaps..

i will look for your diagrams in hopes to improve saftey.

thx

[off the wall]

It's in this post:
http://www.anotherpower.com/board/index.php/topic,902.msg10541.html#msg10541

The manual changeover switches are break before make, with a neutral position, but changing on those at random points in the cycle aways caused disturbance to appliances whereas the automatic switch gives no more than a momentary glitch.

Best wishes

OTW

[toxsickcity]

a simple thought comes to mind.

with a relay. when power is disconnected the output is opposite and spikes as for the need for a diode.

your comments regards shutdown inverter seems something similar...
if so i imagine inverter shutdown may have a spike worthwhile some1 with scope should check..

as i mentioned i will use inverter as ac output never as batt chrg. so will be always on!

im getting xcited for this new inverter..

[oztules]

No...... no diodes on the output.... it's ac not dc, so there are no inductive spikes you can quench like that.
The h bridge effectively clamps that too I think.

I have had 8kw loads cut off by o/load relay I had on the output, and the inverter does not care... at all.

It is not back EMF from the load that is the problem.... it is the inrush current in the primary of the torroid that stinks things up. It is worst when this happens at zero crossing, if reconnection happens at the peak of the wave, then no problem ( opposite to gut feelings I know)

If you never use the AC inputs, you should have no problems with what you want to do. You can shut loads on and off all day, and have no impact.
The inverter will not care if you auto switch  like OTW or manual switch...zero cross switch or any other option...... it has the surge ability to cope regardless. Even if the loads appear as a short circuit due to timing of waves... it won't care. LF inverters are very tough... hf inverters.... not so much.

I was running a threephase 3kw VFD all day yesterday ( driving a desalinator), and no problems with that load either... (poor power factor due to topping the crests of the waves, then leaves the rest of the wave intact....... distortion aplenty).



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

[augustus]

One of my transformers is missing!
Here are a few pics of my "8000w lfpsw 120" powerjack i bought early december.
It seems to be one short in the transformer dept!
Augustus

[oztules]

I wish I was surprised 

I have to assume you "won" an auction.

They really try hard to shoot themselves in the foot.

At least it will start anything you throw at it, but your constant power should be less than 2kw to keep it cool enough in operation..... it will still be a very useful unit.


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

[off the wall]

Oh dear. That was what I experienced a couple of years ago and why since then I only buy through Cher and advise other people to do likewise.

There is an upside to this, however . . . If you buy a genuine unit through Cher - it won't be as cheap as you think you can get it on ebay - then you can use the transformer of this unit in parallel with the two in the new unit and then get a happy 5kw output.

Best wishes

OTW

[augustus]

Hi Oztules and otw
I am in the process of starting a paypal dispute over this, I have several sellers spec of this model powerjack that say that the 8000w inverter does indeed have two transformers and that the seller has issued an obscured warranty number, so Ill see what happens!
regards
Augustus
ps does anyone have an official powerjack photo showing the two trannies?

[ClockmanFrance]

Hi,

I bought 2 PJ's early this year on fleebay auction. A 10000 and an 8000. I paid very little for them so I expected not a lot.

My 8000 has 2 small toroid's inside and they are small.

The 10000 had 2 largish toroid's still to small in my opinion, but the case width limits the size. I dismantled the 10000 and stripped for spares, boards, 4 fans, etc etc. I took one toroid apart and used its copper and mylar on a OzInverter .

The PJ's were cheap.

It seems to me that PowerJack sell good and bad. The company China based that I purchased are no longer around and checking with other fleebay powerjack sellers they all seem to disappear, and those that used to sell PJ boards do not seem to know what they are talking about.

So I conclude that their are Chinese's business folk that buy a cheap batch of Inverters from PJ and retail them to make a fast buck.
 
Sad really as PowerJack seem to shoot themselves in the foot in the long term.

[off the wall]

It would be interesting to see the photos of the 8000 with two small toroids . . .

Best wishes

OTW

[ClockmanFrance]

OTW,
Here you are. The PJ 8000, 48vdc 230ac its torroids are 160mm dia full wound, total weight of 29kgs......

The Core sitting on the case is from the PJ 10000, its 160mm dia and weighs 7.5kgs. When it was fully wound it filled the inside width of 195mm of the PJ case. (but sadly still to small for my OzInverter).

Sorry, I only seem to be able to do one photo per post, French blocking site so I am using a German Proxy server...........