I recently bought a Bison BX6-250 Arc welder from Lazada.  It has an 8 position rotary switch on the front which increases the output amperage from level 1, lowest, to 7, highest , with an Off position.

 

The first problem was that it was supplied with an electrical input "pigtail" with a Shucko connector on the end.  The manual clearly states that the input wiring should be at least 10MM2, but this "pigtail" was 3C x 2.5MM2.  I fixed that by installing a short pigtail using 3C x 10MM2 VCT and a 32 amp connector.  All was well and the unit functioned properly, I thought, thru all 7 switch positions.

 

But , clumsy me, dropped a heavy piece of metal and broke off the switch shaft and knob.  I could still use it by removing the cover and changing switch positions with a 6mm wrench on the shaft that protruded from the back of the switch.  I looked at the switch and found markings indicating that it was a 380/220 VAC 25A switch.  I searched eBay and found one and after a month of Sundays it arrived yesterday from China.  It looked like the right one so I installed it this morning, which required disassembly of the whole freaking unit.  The first thing that I found was that the new switch had 8 different connections, one for each position.  But the old switch only had 5 connections even though it had 8 detents on the switch.

 

I installed the new one using only the first five connections , so now my welder works on switch positions 1 - 5, but is off in positions 6 and 7.  What I found was that the old switch was actually a 6 position switch made to look like an 8 position switch.  Switch  positions 6 and 7 were actually shorted internally to position 5 so that when you switch to these positions they had the same current output as position 5.  I guess that the only way to be sure that you are getting what you pay for is to open it up and inspect it before you buy.  I guess that it costs less to manufacture since the transformer can be smaller since it has less windings!

Buying cracker box Chinese welders online is almost as silly as ordering parts for a broken one. There's a reason most local builders leave them behind on building sites after the job's done.

I don't think it's silly as they work  and are acceptable for the limited amount of welding that I do.   I broke it, it didn't go tits up on it's own,  that's why I ordered the part which was less than 10 % of the cost of a new welder.  I could have ordered the part from the UK for 17 GBPs plus 25 GBPs shipping but most likely got the same part made in China.  The one that I got was 12 GBPs delivered.  I was only commenting about the deceptive design.  I read somewhere that Bison welders are actually made in Poland with Chinese parts, that would be an interesting discussion, a Polish built Chinese welder, would it be Polese or Chinish?

 

I intend to do the same thing with it that local builders do, leave it right where it is when I kick the bucket!

Actually from looking at the 3 units sold through Lazada two of them clearly indicate peak power is position 5 of the switch (the 3rd unit has no such increase width graph on panel) so it appears the same case/switch is likely used for other amperage units that might use position 6/7 for increased power.  I would not call it a scam - it seems to have been designed to peak at position 5.

 

Edit:  I stand corrected - it is the same unit and model number but name is Sun rather than Bison - time for coffee.

I went back and looked at the ad for the one that I bought, http://www.lazada.co.th/bison-250-bx6-250-548060.html,.

There is no such disclaimer there that I see.  You would assume that if it has an 8 position switch that it's output power would increase all the way through position 7 and not have position 6 and 7 be the same as position 5.

Yes but if you paid an extra 1k for the Sun unit it would have been at least a bit more obvious.  But do not believe it was designed to scam anyone - the full power is indicated and expect that is what is delivered in 5/6/7 - just cheaper to use the switch/faceplate they have available then obtain another I suspect.

Interesting point, pay an extra 1k to be told up front that switch positions 6 & 7 are the same as 5.  I probably would never have found it if I hadn't been a clumsy goof and dropped the piece of metal. 

 

I just feel that it is total misrepresentation.

That was a tongue-in-cheek comment.  Sorry it was not clearer.