Question for Electricians

[orion.osiris]

Hi all,

I have a garage with conventional power and light fitments. Power comes in via what appears to be armoured cable and goes into a good old fashioned fu sebox/mains switch. The box says 'maximum load 45 amps' and there are two f uses under a removable cover which are 5A and 20A for light and power respe ctively (I assume). Nice and simple for someone of my generation. :-) Now, I need to connect up a 3-phase lathe via a single-to-three phase conve rter. The lathe and converter to run it are both rated at 2.2kw or 3 horsep ower if you prefer. I also have a fairly substantial arc welder which is ca pable of up to 300 amps if fed by a 3 phase supply, or 220 amps via 230v si ngle phase. Would I be right in thinking the best thing to do here is install a mini di stribution board between the main fusebox and the new appliances (or replac e the fusebox altogether with it)? Everything is still running off of 230V to begin with, but at more than the 13A your standard sockets are capable o f sourcing. So should I fit out the new distribution board with a couple of 16A RCBOs if that's the way to go? Also the people that are supplying me the phase converter say that while it will happily run the lathe, it won't supply the welder for some reason. An yone know why not?

[ARWadsworth]

A week is a long time in electrical generation

"Oh, and before some helpful soul offers up a practical solution, such as "get yerself a phase converter, mate, it's a lot cheaper" I should just point out that I'm NOT looking for solutions, here, I'm simply enquiring as to whether my understanding of the basic situation is correct or not. Thanks!"

[Bob Minchin]

Because the converter is designed to 'see' a motor as the load and relies on its windings to help balance the phases. Ask your suppliers about a rotary converter for use with a welder. These have a motor inside and are more tolerant of other loads. They may or may not approved their rotary converters for use with welders. NB they will cost you a lot more than a static converter.

[Graham.]

You could say his project (and his mindset) has entred a different "phase". Nothing wrong with that.

[John Rumm]

It would probably be easier to simply replace the old fuse box with a new CU with enough ways to deal with all the circuits.

Yup, and you can feed the blue command style sockets if you want...

Probably because they are designed to work with motor loads that have rotational momentum of their own.

[DerbyBorn]

[e-mail] wrote in news: [e-mail]:

What is th erating of the circuit supplying the armoured cable? Someone needs to know.

[harryagain]

I have a garage with conventional power and light fitments. Power comes in via what appears to be armoured cable and goes into a good old fashioned fusebox/mains switch. The box says 'maximum load 45 amps' and there are two fuses under a removable cover which are 5A and 20A for light and power respectively (I assume). Nice and simple for someone of my generation. :-) Now, I need to connect up a 3-phase lathe via a single-to-three phase converter. The lathe and converter to run it are both rated at 2.2kw or 3 horsepower if you prefer. I also have a fairly substantial arc welder which is capable of up to 300 amps if fed by a 3 phase supply, or 220 amps via

230v single phase. Would I be right in thinking the best thing to do here is install a mini distribution board between the main fusebox and the new appliances (or replace the fusebox altogether with it)? Everything is still running off of 230V to begin with, but at more than the 13A your standard sockets are capable of sourcing. So should I fit out the new distribution board with a couple of 16A RCBOs if that's the way to go? Also the people that are supplying me the phase converter say that while it will happily run the lathe, it won't supply the welder for some reason. Anyone know why not?

When you scrape your electrode across a job, all sort of nasty voltage spikes are created theat elesctronic devices don't like at all. You would be well advised to make sure your inverter (For the lathe motor) is isolated from the mains when you are welding.

The motor inverter is just for motors. For example it will have "soft start" technology built in to limit the starting current of the motor. This would be well and truely f****d up by an electric welder. Also electric welders have very poor power factors, probably outside the range of this device.

Many of them will correct poorish power factors associated with induction motors.

[Tim Watts]

On Sunday 14 July 2013 19:42 harryagain wrote in uk.d-i-y:

That's what I saw ^^^^

Was that a quote or what?

[orion.osiris]

I'm guessing basic English comprehension wasn't your strong suit at school.

[Andy Burns]

It's the best Harry can manage; out of the gmail frying pan, into the outlook express fire.

[John Rumm]

Shall we tell him about OEQuoteFix?