Hi all, needing a wee bit of advice/help.

We have a power perfector installed within one of our buildings & the contactor has used three single core 185mm2 coil end lead cables to supply the PP. The single core cables feeding the PP are glanded individually through the aluminum top plate of the PP through separate brass glands which have rubber inserts.

The question is, will this create/induce eddy currents?? The contractor said it wont because the plate is aluminum.

Your comments would be appreciated.

Thanks

It needs to be ferrous to allow the induction of eddy currents.

Aluminium is non magnetic (and non ferrous) so you won't have an eddy current effect.

It's why we use aluminium gland plates on big switchgear that has single core supplies

Regards

OMS

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Failure is always an option

Thanks for the speedy reply OMS.

Regards,

CPC

Hm, true, but doesn't old leccy meters depend on eddy currents in an aluminium plate to go round? Think of spinning an ally plate and put a strond hard disk mag next to it...
Just a thought...

Just a thought, is it not the case that aluminium is paramagnetic and iron is ferromagnetic, its all to do with the atoms, see I did learn something. LOL

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Going back to my television engineer days I remember that the Philips video recorders, (mid 70's, N1500 series) had an Eddy current brake which consisted of an aluminium disc running beween two halves of an electromagnet which was connected to the motor servo circuit. Never quite understood how it worked but it did!

Dave.

No it won't that's why AWA and is seldom used as opposed to SWA for singles going into ferrous materials.

Will you stop it !! -

Two atoms are walking down the street. Says one atom to the other, "Hey! I think I lost an electron!" The other says, "Are you sure??" "Yes, I'm positive!"

In the OPs situation, where is the strong permanent field coming from - will the paramagnetic effect of aluminium happen ?


OMS

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Failure is always an option

All materials have magnetic fields because electrons are constantly moving about, in ferromagnetic materials they are aligned so one magnetic component is stonger than the other, in paramagnetic materials the magnetic components are aligned so they cancel each other out.

It all comes down a sprinkling of quantum mechanics, the ability of a material to conduct magnetic flux is called relative permeability.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Seldom - I'd say never.

And BS 7671 prohibits it anyway

Regards

OMS

-------------------------
Failure is always an option

LoL - so it is rocket science after all !! -


OMS

-------------------------
Failure is always an option

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

What about the possible electrolytic corrosion between the Al & the Brass though?...
Electrochemical series anyone?

RnR, please don't start on such topics they give me headaches these days

Quantum things, the nearest I get is old episodes of Quantum Leap these days!

Well Al will be the less noble - but I'd like to think there won't be too much of an electrolyte present around a brass gland and an Al gland plate

Regards

OMS

-------------------------
Failure is always an option

AWA is not allowed?

OMS,
Are you sure about that?
Rain water, tap water, both good electrolytes as you know!

AWA is allowed - single core SWA isn't

regards

OMS

-------------------------
Failure is always an option

For the reason of eddy currents? AWA is allowed though isn't it?

should of used aluminum glands

For sure - but would you expect rain water or tap water on the alu gland plate on the top face of a power perfector in a switch room. Even if you do get a touch of moisture, the internal heating of the PP would evaporate (quickly) any liquid. I also wouldn't expect too much of an environmental humidity problem in a switchroom

Aluminium glands as mentiond above would be another option, but we dont know the cable type used

Regards

OMS

-------------------------
Failure is always an option