3phase problem

[stevethejoiner]

Oh dear, I thought the photo's would help,

From what I can tell, the live,neutral and earth we can see at the front of the starter at terminals A-B-C go to the motor.

The three incoming black live supply wires connect to the terminals at the rear of the starter, and its earth is terminated at the casing on the back of the starter housings metal box.

 

[JohnW2]

Is that an earth connected to one of the phases of the motor starter/overload?

... or maybe brown-blue-G/Y flex has been used for the three phases?!

Kind Regards, John

 

[ban-all-sheds]

Maybe.

Which would make one worry/wonder about

... a professionally restored woodworking machine ...

 

[JohnW2]

Maybe. Which would make one worry/wonder about

... a professionally restored woodworking machine ...

It would.

Kind Regards, John

 

[ericmark]

St Fagans National History Museum has quite a few professionally restored machines but often there is no intention to use the machine it is only for display.

To my mind if you wanted to actually use the machine then although it may not be original equipment one would install modern starters and also of course all the modern safety switches.

In one place I worked we used very old concrete presses which originally had a whole series of levers and controls the press was well made and very good but the controls when straight into the bin and replaced with a modern PLC control system. I am sure the original designer would have been impressed to see 6 washing machine weights per minute rather than one paving slab every 2 minutes.

But what you show does not seem to comply with modern working practices and I think St Fagans National History Museum is the best place for it.

 

[stevethejoiner]

First and update.
Yes it is the starter, it is wired correctly, but just not working as it should. The electrician got the machine running by manually doing something with the starter.
So a new starter is to be fitted. Who will pay? I suppose it should be the supplier as it is meant to be working and therefor not fit for purpose.
Thank you all.

 

[stillp]

First and update.
Yes it is the starter, it is wired correctly,

No it isn't - it uses the wrong colour conductors.

 

[stevethejoiner]

St Fagans National History Museum has quite a few professionally restored machines but often there is no intention to use the machine it is only for display.


But what you show does not seem to comply with modern working practices and I think St Fagans National History Museum is the best place for it.

I should like to comment on the above.

Agreed, the machine has to be safe and legal, but you cannot write off a machine to scrap or put it in a museum because of its age, or assume modern is better.

I qualified as a wood machinist and joiner in 1975 and I can state that modern machines are no match for these old beauties. Their heavy cast iron build makes them extremely stable, which in turn makes them safer when feeding heavy timbers through them. The build quality also gives greater accuracy for setting up the fences and guides, and once set up they don't move. They can be made PUWER complaint, as will this machine when the extraction is fitted. As a rule, things do not break on these old machines as they are so well constructed. They do not rust away, they hold their value, in fact they actually appreciate in value, unlike light modern equivalents.

 

[stillp]

In general I agree, but these older machines often don't have adequate guarding or anti-kickback fingers, so can be more dangerous. When you qualified in 1975 I bet many of the machinists you knew were missing a finger or two.

(I speak as someone who first used Wadkin planers in the sixties, and I have a 1972 Lurem combination at home)

 

[stevethejoiner]

First and update.
Yes it is the starter, it is wired correctly,

No it isn't - it uses the wrong colour conductors.

I am in the middle of electricians disagreeing here. The electrician from Electogen Ltd in Bethersden Kent., who tested it today says its wired ok, but the starter is at fault.

The company who supplied the machine said to me today when I said it needs a new starter. It was working when it left here, what did your electrician do to it? Errr nothing, he just looked and tested as it was not working, da!

You are now saying from my photo it is wired wrong.

I think I need another opinion.

 

[stevethejoiner]

In general I agree, but these older machines often don't have adequate guarding or anti-kickback fingers, so can be more dangerous. When you qualified in 1975 I bet many of the machinists you knew were missing a finger or two.

(I speak as someone who first used Wadkin planers in the sixties, and I have a 1972 Lurem combination at home)

You are almost correct. I do not recall any machine that didn't have cutter guards. But then, back in the 70s we did not have HSE governing what was done, and the machinist, or spindle hand, did what they wanted to get a job done. That more often meant they did not use the guards, work hold downs, riving knives, crown guards, push sticks and other safety devises, so fingers got too close to the cutters.
Employers were not prosecuted when employees lost fingers as it was deemed to be just employee ceaselessness, so they just had a few weeks off work to recover.
The machines were rarely at fault.

 

[Aragorn84]

Its wired with the wrong cable.

Its not permitted to use green/yellow cable for anything other than earth, whereas in this machine its been used for one of the live phases to the motor.

The green/yellow wire might well be connecting the right terminal to the right place on the motor, but that doesnt change the fact that its wrong.

 

[sparkwright]

What a beautiful machine.

I think on a previous topic we did decide it was 'acceptable' to use the green and yellow of a FLEX as a live conductor IF it was sleeved an appropriate colour.

Acceptable but very bad practice.

I don't think we even considered 3 phase.

I would have hoped the repair company would have changed that for you, to save any confusion.

 

[JohnW2]

I think on a previous topic we did decide it was 'acceptable' to use the green and yellow of a FLEX as a live conductor IF it was sleeved an appropriate colour. ... Acceptable but very bad practice. ... I don't think we even considered 3 phase.

Indeed - and I'm sure we didn't (even consider 3-phase). Even with this very bad practice, the blue, as well as the G/Y, presumably needs appropriately over-sleeving if it is also being used as a phase conductor.

I would have hoped the repair company would have changed that for you, to save any confusion.

Quite so.

Kind Regards, John

 

[eveares]

Just to help the poster (steve), Old colours/new harmonized wiring colours below.

Red/Brown = First phase

Yellow/Black = Second Phase

Blue/Grey = Third Phase

Black/Blue = Neutral

Striped Yellow & Green = Earth


Also worth while checking any motor run or starter caps have not failed/blown or come loose, and that any centrifugal cutout switch in the motor is operating normally. Same goes for all other connections, check for loose wires to wingdings, etc...

Note the caps if it has any, may be attached to the motor it's self or in a small attached box and the centrifugal switch built into the motor it's self.


And for the techies on here, I know phase N is correctly referred to as line N where N is phase/line number (1-3).