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1338 views
05:12 Jul-08-2008
ndtman
MPI: Aluminum vs copper central conductors

I have a requirement to circularly magnetize a hollow shaft (approx. 10 ft. long) using a rod at 7500 amps. The procedure does not allow the use of flexible cable. I intend to use a 2 inch diameter (12 ft long) copper rod as a central conductor but it is very expensive. Could I use a 2 inch diameter aluminum rod in place of the copper rod? Will the flux density at the surface of the part be the same as the copper conductor?




 
00:11 Jul-08-2008

P V SASTRY

R & D, NDT tecniques metallurgy
TAKEN VRS FROM THE POSITION OF SR. DEPUTY GENERAL MANAGER BHEL CORPORATE R&D,
India,
Joined Jan 2003
195
Re: MPI: Aluminum vs copper central conductors You may use any conductor as long as you can pass the required 7500 amperes. The flux is a function of the current and not the conductor. You are required to keep the conductor at the centre so that the flux is uniform.This is the reason for prescribing the rod conductor and not allowing the flexible cable which is difficult to keep at the centre.

However Aluminium conductivity is only 62% of that of copper. So for the given current, the cross section of the Aluminium conductor goes up in proportion and so is the cost. The increased dia. of the conductor has a bearing on the flux depending on the ID of the part which is not mentioned.

You can also use a copper tube with lesser overall cross sectional area that has certain advantages.

----------- Start Original Message -----------
: I have a requirement to circularly magnetize a hollow shaft (approx. 10 ft. long) using a rod at 7500 amps. The procedure does not allow the use of flexible cable. I intend to use a 2 inch diameter (12 ft long) copper rod as a central conductor but it is very expensive. Could I use a 2 inch diameter aluminum rod in place of the copper rod? Will the flux density at the surface of the part be the same as the copper conductor?
------------ End Original Message ------------




 


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