cut 50 question

[decca]

Hi. I am setting up my cut 50 plasma cutter but it does not have a plug fitted and the wiring is strange colours. See photo

The earth is no problem but I dont know if the green or black is live. Also the machine says 220v will this run on UK mains at 240v. I would be greatful for any advice before I blow it up.

Cheers
Brian

 

[gaz1]

unscrew the box and trace the wire is my call dont rely on what you may think it is earth you will see as its earthed to box somewhere

live and neutral trace to pcb board and then check which is live

also it maybe worth a rewire for your own safety

 

[rtbcomp]

If either of the green or black go to a fuse that will be the live.

Do you not have a user manual for it?

 

[skotl]

As suggested, trace the cables to figure out which one is the earth. Do you have a multimeter? If so, stick it in resistance / diode mode and measure between each of the three wires and that earth screw on the back. The one that reads 0 ohms / short-circuit is the earth lead.

It's almost certainly going to be the green and yellow but I would definitely triple check.

For the other two cables, both go to the double-pole switch (there is no internal fuse on mine) so it doesn't matter how you attach them to neutral and live.

 

[ukracer]

It's almost certainly going to be the green and yellow

You have faith in them there chinese. I know of a company who asked for English plugs to be fitted. instead of 2 pin. Which was fine BUT upon inspection the earth wire was cut of at the appliance end..................yet another reason why I fell out with them I insisted they were all rewired and PAT tested but they did not like that .

Your treble check seems good advice
.....

 

[rtbcomp]

...........
For the other two cables, both go to the double-poll switch (there is no internal fuse on mine) so it doesn't matter how you attach them to neutral and live.

But if there's a mains fuse inside it needs to be connected to the live conductor, otherwise if it blows the whole unit will remain live.

It could be the double pole switch is also a cut-out in which case you should be OK either way.

 

[decca]

Thanks guys.
I do have a manual but it is crap.
Have removed the case and as Skotl says both cables go to the switch , no fuse in sight then onto this board .

Both wires end up on this board.The yellow and green is earthed to the chassis of the machine so that should be fine. I will connect the plug and give it a try.

 

[skotl]

Yup - that looks the same as mine, internally.

If you have any blue and brown sleeving then it would be very useful to put a bit of sleeving at the plug end and switch end. As RTB suggests, it's healthier to know which is the line (previously known as "live") conductor (although it's commonly misunderstood that in a functioning device, the same voltage and current is present in both Line and Neutral).

 

[mr migwire]

any pics of the back of the switch mate? ive just replaced the mains switch on my cut 50 as the old one burnt out and the colour scheme for the wiring is a bit funky.
edited to add the mains cable on my machine had already been replaced for a uk spec cable, but the bottom of the swith to the board was original wiring which is green and black if I remember correctly.

 

[skotl]

any pics of the back of the switch mate? ive just replaced the mains switch on my cut 50 as the old one burnt out and the colour scheme for the wiring is a bit funky.

Still on me phone from when I first took it apart back in December;

 

[skotl]

^^^ photo has flipped 90 degrees. FYI, the top two connectors on the switch are empty.

 

[rtbcomp]

.............. (although it's commonly misunderstood that in a functioning device, the same voltage and current is present in both Line and Neutral).

The current's the same.

As for voltage you always measure that relative to another point, so you could say the line stands at 220v with respect to neutral, or neutral stands at 220v wrt live. Usually you state mains voltages wrt earth, so line stands at 220v (wrt earth implied) and neutral is at 0v (or a few depending on the installation).

 

[mr migwire]

I wonder if they just use whatever cable is available for these things

 

[skotl]

The current's the same.

As for voltage you always measure that relative to another point, so you could say the line stands at 220v with respect to neutral, or neutral stands at 220v wrt live. Usually you state mains voltages wrt earth, so line stands at 220v (wrt earth implied) and neutral is at 0v (or a few depending on the installation).

Good point - I was mistakenly over-stating the danger in assuming that neutral was safe, but that would only be the case if neutral was not bonded to earth.

Apologies for the off-topicness...

 

[skotl]

I wonder if they just use whatever cable is available for these things

Looks like yours and mine came with UK spec cable, but the OPs still had the Chinese cable attached which will, as you suggest, appear to be off whatever drum was on the bench at the time!

It's amazing these things work at all, really

 

[mr migwire]

Looks like yours and mine came with UK spec cable, but the OPs still had the Chinese cable attached which will, as you suggest, appear to be off whatever drum was on the bench at the time!

It's amazing these things work at all, really

I have a hanshen 200amp dc tig which when powered on goes straight to an oc red light on the front panel and wont do nowt. it worked fine for a couple of weeks then one day I switched it on and this..... maybe have to get you to have a squiz skotl, very similar boards to the cut 50.

 

[eSCHEn]

I have a hanshen 200amp dc tig which when powered on goes straight to an oc red light on the front panel and wont do nowt. it worked fine for a couple of weeks then one day I switched it on and this..... maybe have to get you to have a squiz skotl, very similar boards to the cut 50.

It begins

 

[mr migwire]

It begins

got to get him started...lol

 

[eSCHEn]

got to get him started...lol

Now that he's fixed the Cut50 he'll be bored and have nowt to do as well. You're a true gentleman Mr Migwire in giving him this to do. He's lucky we're here to stop him being depressed.

 

[skotl]

got to get him started...lol