Workshop feed

[JFC]

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Hi all . New here and i run a joinery workshop from home . A few months ago i managed to buy a few Wadkin machines for my workshop and managed to blow one up :C

I dont understand so i hope someone can help me here . The machine is a Wadkin BAO's planer thicknesser .

Spec here

http://i31.photobucket.com/albums/c368/JFCarpentry/006-19.jpg

I knocked the off switch while it was under load and hit the on switch a the second i heard it lose power . The thermal overload in the isolator didnt cut the machine out so 58 amps got put into the machine until the load was cleared .

The Brook motor is dated 1959 and i have had it rewound , new bearings and have had the machine rewired with a new isolator and 16 amp plug ( its a 240volt motor , special order from Wadkin )

Anyhow everything is all fixed and i'm a happy bunny but the experts that fixed the machine for me are saying my armoured cable supply to my workshop isnt big enough and that is what melted my motor and not to use the machine untill i have upgraded the supply .

Most electricians i have spoken to have looked puzzled at this as my lights flicker but dont dim when i start the machines but i am told by the experts that we are talking old style electrics when the voltage used to be 250 V but now we have 230 V .

The 40 meter run of cable i have to the workshop is also losing power and as the cable is small that is also losing power .

Wadkin ( or the company that have taken them over ) say if the machine doesnt have the right power then it just wont start .

It doesnt bother me to put in a new feed if its needed , i guess it would cost around

 

[steptoe]

first up, we need to know the size of the supply cable at present, and what sort of loading you are likely to be using in the workshop,

then we can advise on what size of cable you actually require.

 

[Doc Hudson]

Welcome to the forum, Volt drop could a pivotal; issue at 40m run. But first we need Steptoes questions answered.

Doc H.

 

[JFC]

Just had a look and its 42mm if i wrap the tape around it and 12mm across .

The start up load in the manual is 65 Amps but then drops down to under 10 ( i think ) The start up was meausered as 58 amps with a testy thing .

 

[steptoe]

12mm, thats a small cable,

can you read any of the actual writing that is stamped on the cable?

that will tell us the actual core sizes, but at 12mm I guessing 2.5mm 3core at a push TBH,

its deffo nowhere near what you need for a load like you have, we also need to allow for start up current as well on your machinery.

 

[SLIPSHOD & SLAPDASH]

No mention of an earth rod yet (gasp in horror !!)

 

[Doc Hudson]

It is the cross sectional area of the actual conductors that is needed. but 12mm is not very big. Is that a 3core or 2 core cable?

Doc H.

 

[JFC]

I cant get to the cable as its all sealed in a conduet with just the ends going into the fuse boxes at both ends .

 

[SLIPSHOD & SLAPDASH]

What size fuse/breaker is at the house end fuse box and any chance of a pic of the cable ?

 

[JFC]

It is the cross sectional area of the actual conductors that is needed. but 12mm is not very big. Is that a 3core or 2 core cable?Doc H.

Im a carpenter and joiner mate . I just do wood stuff and have no idea about electrics . When the electrician turns up on site he normally turns the power off so i go home .

 

[SLIPSHOD & SLAPDASH]

Good with wood

 

[kme]

Sounds like you`re seriously undersized on your supply cable - though a pic would REALLY help.

Sidewinder is the resident woodworking equipment specialist - though, in this case, I don`t think its an equipment-specific fault, TBH.

 

[JFC]

Thanks for the fast replies . I hope this picture helps .

Sorry for the links but i cant seem to get a picture to show on here for some reason .

 

[Sidewinder]

jfc,

Welcome to the forum. :Welcome:

Can you please measure the diameter of the cable at the top right of your picture for us?

We could also do with knowing if it has 2, 3, 4, or 5 cores in it, I realise that you have a single phase install, but that does not tell us what cable has been installed.

Is there any length of the outer of this cable visible anywhere, if so can you read the markings on it to see if it says something like "BS5467 3 x 10" or the like embossed into the sheath as that would tell us what we need to know.

I know the BAOS I am going to look at 2 tomorrow for 2 separate customers! Good little machine.

I doubt that the scenario you describe would cause issues, unless the motor was stalled?

I am guessing that you either had AMD or Daltons to do the machine for you as those are the 2 companies that bought the rights to the Wadkin machinery range when the went through for the final time.

The supply voltage in the UK i snow a "nominal" 230V, where as i used to be a "nominal" 240V.

We could do with knowing as accurately as possible the length of run of the cable and what else you use in the workshop.

BTW, are you running a business from your home? If so please be sure that your house & business insurances are suitable as if there were an incident then you could have issues.

The picture you have posted looks like the electrical system in your workshop, which if you are running a business would not comply with statute law.

 

[JFC]

I found a bit . It looks like it says BS3907 . Its about a 40M run and the picture is at the house end . Running a business from home , not me Sir :innocent

The machine was under load when i knocked the off switch and then the on switch so yes the motor or the cutter block was under load and the start up load was put into the machine for a fair while .

The diameter of the cable is 13mm ish .

There are a few other Wadkins in the workshop aswell as dust extraction , air cleaners , oil filled rads , lathes , power feeds , its probably quicker to list what i dont have in there Just me in there so not all running at once .

 

[ProDave]

Whilst I agree the cable sounds under sized and the result is excessive volt drop, I do NOT susbscribe to the theory that this will damage the machine or cause excessive power.

The motor burned out (probably) due to operator error trying to re start the machine while it was still running.

The cable size being talked about (13mm across) sounds to me like no lore than 2.5mm which is far to small for that run and that load.

Re the voltage now being "230V" I wouldn't let that trouble you. that's a load of tosh really. Several years ago we "harmonised" our supply with the rest of europe, but they "bent" the rules by saying it would be 230V +10% / -6% That +10% limit allowed the DNO's to just carry on supplying us with 240V and it was still within the acceptable limits. If you actually measure your supply voltage, I would be VERY surprised if you only had 230V coming into your property. Here, it's nearly always 246V whenever I measure it.

Upgrading the cable will be a good idea. It will stop the lights dipping on start up, and help the machines get going. The only time under voltage could cause a problem would be if the voltage dropped so low that the machine could not start, then you would be driving a stalled motor, which would draw a lot more current. But the machine designer should have included an overload trip to cut the supply before the motor burns out.

 

[apprentice87]

Hmm, I have personally seen a motor on a clarke air compressor installed on a farm [where else!!!!] that was on such a run of cable that it would not start properly off load never mind when the tank was full, that lasted about three days until it failed to start. The run was that long, and, as there was no proper motor protection, there was no OCPD to trip and so the poor old motor got hotter and hotter and hotter until it actually melted into a clump of BOTH aluminium and plastic!!!

The replacement motor lasted about three days too. Some people [farmers] will just not be told!!!

john..

 

[JFC]

Well i dont want to be melting any of my motors let alone this one that i have just had rewound ,

So what cable should i be getting to do the job ? Its a 35M run so i guess 40M of cable should be about right .

 

[Zeespark]

Can you get us a pic of the details plate on the motor JFC? Where roughly in London are you?

AndyGuinness

 

[steptoe]

dunno if it still works but I use either the 2.5 or 3x rule for motor start-ups, then add on the other loads being used simultaneously,

so that would be , add up all the normal usage loads and the add the biggest motor current x3, maximum demand,

remember to allow for the biggest run load being used at the same time as the biggest start-up.

no doubt some-one will tell me thats not how to do it these days, we need a calculator and reams of paper to work it out,

oh, in case I forget, what sort of earthing system do you have? ]