Wire Quality Inspection

[mbailey]

I am wanting to start in incoming inspection process on both round and rectangular magnet wire. What are the critical features I must measure in order to evaluate the wire quality? Does anyone have a feel of minimum acceptable dielectric breakdown voltages?
Thanks. MBailey.

 

[aolalde]

Consult NEMA Std Publication No. MW 1000, Magnet Wire.

 

[mbailey]

NEMA is the absolute minimum standard which any wire supplier should be capable of meeting. It was written by the wire manufactures, not the wire users. Of the parameters listed in NEMA, which ones are the most important? Which ones require measurement? Thanks, mbailey

 

[Tmoose]

I'm working for an outfit that makes linear motors. They design their own coils and make their own stators. They worry about operating temperature and specify 200 C rating or higher, which seems to automatically mean the double thick stuff. The winders like the toughness of that insulation, and having tried to wire brush it off, I concur the insulation is resistant to abrasive damage and TOUGH. Still, I believe the failures they've had have been related to mechanical insulation damage, not so much during coil winding but from installation in the back iron which they make too snug due to deep seated fears of an extra mm of potting material causing overheating.

 

[mbailey]

Thanks Tmoose,

I trying to develop a specification that will apply minimum limits to such tests as the Thermoplastic Flow and Dielectric Breakdown Voltages as well as burrs and conductor damage. I'm looking for requirements that others may have experience with because the NEMA MW-1000 standard is only an industry minimum. We use the dual film wire with EAI base coat and AI top coat also and although it may be tough, how tough do we want it and how do you measure that toughness? Are others testing the wire that they receive from wire suppliers and what testing do they do?

Thanks, mbailey