3M Flexible Insulation

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Electrical Insulation

Application Guide

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3M CeQUIN I, II and CeQUIN3000

The 3M CeQUIN product family consists of soft, conformable mineral papers. They are typically designed for vacuum pressure impregnation since the open structure of the material allows for excellent absorption of resins. Withthe ver high mineral content they excel in thermal conduction and resistance to partial discharge.
Besides its use in dry type transformers CeQUIN has also proven to be an excellent insulation material also for high temperature strip wound magnet coils often used in lifting and separation magnets.
Where other materials like mica or aramid papers have slippery surfaces the soft CeQUIN allows for tight winding of the magnet coils thus avoiding telecoping during their assembly process.

Features and Benefits:

  • UL1446 and IEC 60085 fir use in Electrical Insulation Systems (EIS)
  • Ul & CSA certified for class R(220°C)
  • Free of halogens as per IEC 61249-2-21
  • Compliant to REACH (SVHC's) as per Art.59 EU Regulation Nr.1970/2006 to Dec.2013
  • RoHS compliant as per 2011/65/EU

Typical Applications:

  • Ground/interwinding insulation in dry type transformers and magnets
  • Core wrap and end fill in dry type transformers
  • Barrier insulation
  • Spiral and Convolute Tubing



Rectangular tube in CeQUIN II 60mil/1,5mm, interlayer insulation in CeQUIN 7mil/0,18mm, spacer sticks in CeQUINBORD

3M CeQUIN Inorganic Insulating Paper is 3M’s highest inorganic-content paper; comprised primarily of glass fibers and microfibers, inorganic fillers, and less than 10% organic binder. It is capable of performance at temperature peaks up to 250°C and is a highly flexible paper. This paper has found a wide variety of uses over the years but its main use remains as interwinding insulation for foil wound dry-type transformers.

3M CeQUIN 3000

Heavy duty circular electromagnet in scrap yard

Realized with Cequin 220C for interlayer insulation of the magnetic coil.

3M Inorganic Insulating Paper CeQUIN 3000 is a modified version of CeQUIN I paper developed to provide high-strength thin papers. By introducing a small percentage of organic fiber reinforcement along with a high-strength binder system, Cequin 3000 papers may be produced in 3-mil and 5-mil thicknesses. It may be laminated with polyester film, or glass fabric to enhance initial dielectric strength or improve mechanical manageability.



Spacers in CeQUINBORD and endfills in CorQUIN

CeQUINBORD CGA is a high inorganic content board composed primarily of glass fibers and microfibers, inorganic fillers, and less than 10% organic binders. It is
capable of long-term performance at temperatures exceeding 250°C. CeQUINBORD CGA is available as trimmed 48" x 48" (1220 mm x 1220 mm) boards in thicknesses
ranging from 1/32" (.79 mm) to 3/8" (9.5 mm).


End fills

This diagram displays the use of CORQUIN od CEQUIN II as end fills or outer wrapping in low voltage coils in dry-type transformers.

3M™ CORQUIN is designed for outstanding resin-absorption. Major applications are end fills and spacers in dry-type transformers. It has the same composition as the CEQUIN papers, but due to a different processing, the CORQUIN papers have a lower density than the CEQUIN papers. 3M™ CorQUIN Inorganic Insulating Paper offers thermal and dielectric stability in such uses as spiral wound and other types of core tubes, for insulating systems up to Class 220, per UL 1446 and IEC Std. 60085. It's general characteristics can be summarized with:

- Excellent conformability
- Slightly compressible
- Excellent absorption of resins and varnish

The application of choice for CORQUIN is its use for end fills in the low voltage coil of dry-type transformer. In contrast to aramid papers the conformable structure of CORQUIN adopts easily to the surface on which it is applied and follows it's shape. Being slightly compressible, CORQUIN also allows the compensation of minor variations in the interlayer spacing. CORQUIN's excellent absorption of resins leads to leads to a complete saturation of the end fill in the vacuum-pressure-impregnation process improving the mechanical performance of the low voltage coil.

Technical Documentation