HI-THERM BB-346/A
▪ Black impregnating varnish
▪ Excellent adhesion and flexibility
▪ Superior heat resistance, suitable up to 215°C
▪ Suitable for insulating systems in class A, B ,F and H
▪ Military approved, qualified under MIL-V-1137A, grade CB, type M, and MIL-I-24092,
type M, class 180
▪ UL approved (File OBOR2.E317427 and OBJS2.E317429), included in 130°C, 155°C,
180°C, and 220°C insulating systems
Description
HI-THERM BB-346/A Black Baking Varnish is a modified polyester based varnish suitable for the impregnation of
electrical machinery windings in Thermal Classes A, B, F and H. Long use experiences have proven HI-THERM BB-
346/A to have an excellent dip tank stability, even in the worst using conditions.
Compatible with the following magnet wires coatings: Amide-Imide, Polyamide, Polyurethane-Polyamide, Polyvinyl
Formal, Polyurethane, Epoxy, Polyvinyl Formal-Polyamide, Polyimide, Textile, Polyester Amide-Imide, Polyester.
HI-THERM BB-346/A has a heat life of 20.000h. at 215°C and of 40.000h. at 205°C as determined by ASTM D-3251
(twisted pairs) specifications, using a polyester amide-imide magnet wire
Applications
Impregnation of stators, low speed rotors, transformers, windings, coils.
Processing guidelines
HI-THERM BB-346/A is suitable for both atmospheric pressure and under vacuum impregnations; if necessary, it can
be diluted with DOLPH’S T-200 thinner. The excellent wetting properties assure maximum penetration using
atmospheric or vacuum impregnating systems
The following cycle is recommended as a starting point in the treatment at atmospheric pressure of most units:
1. Dip into the varnish for 15-30’.
2. Drain 15-30' (to obtain a high build-up, we suggest to shorten the draining time).
3. Place in the oven and bake according to one of the following cycles : 3-5 hours at 135°C, or 2-4 hours at 150°C
or 1-2 hours at 165°C (times must be taken when unit reaches the baking temperature)
For specific application feel free to contact us
