Kapton® Keeps Steel Billet Mill Motor Running 24 Hours a Day

Kapton® Keeps Steel Billet Mill Motor Running 24 Hours a Day

Application Description

Iscor’s steel billet mill motor in Newcastle, South Africa has to run under extremely arduous conditions. The 3800 kW DC motor’s armature weighs 103,870 lb (47 tons), is 2.8 m (9.18 ft) in diameter and 6 m (19.68 ft) in length. Operating for 24 hours a day, the reversing mill with regenerative braking puts excessive strain on the insulation system. It failed recently with marked overheating characteristics and with much of the insulation burnt black. Upon assessment, it was decided to rebuild the insulation to Class H specifications using resin rich technology and specifically to change the conductor insulation from double varnished glass to Kapton®, as this was probably the area of the initial failure.

Reasons for Choosing Kapton®

  • High dielectric strength
  • 3 × heat dissipation factor of normal film
  • Resistance to temperature extremes

This information corresponds to our current knowledge on the subject. It is offered solely to provide possible suggestions for your own experimentations. It is not intended, however, to substitute for any testing you may need to conduct to determine for yourself the suitability of our products for your particular purposes. This  information may be subject to revision as new knowledge and experience becomes available. Since we cannot anticipate all variations in actual end-use conditions, DuPont makes no warranties and assumes no liability in connection with any use of this information. Nothing in this publication is to be considered as a license to operate under or a recommendation to infringe any patent right.


Caution: Do not use in medical applications involving permanent implantation in the human body. For other medical applications, see “DuPont Medical Caution Statement:, H-51459 or H-50102-2.