NK 50/90
Application
It is designated for continual impregnation of windings nn of electrical rotating machines of thermal class F by dipping in continuous impregnating appliances. Impregnating resin NK 50/90 can be used also for discontinue impregnation of windings especially from small diameters enamelled wires under atmospheric pressure and also under vacuum.
Impregnating resin NK 50/90 is delivered according to TP 117-ZSE-U-0149/91.
Characteristics
Impregnating resin NK 50/90 is a solution of unsaturated polyesterimid in styrene. Before processing it must be mixed with a hardener TBP in the mass ratio 100:1. Curing time is 2 hours at the temperature 140 °C after the winding has reached this temperature. Elasticity of varnish film after curing is very high along with high bonding strength of winding. It is resistant to vapour solvents, transformer oils and refrigerator liquids.
Tab. 1 Processing data
| Flow time (DIN Cup 4) | 23 °C | [s] | 85 - 95 |
| Density (DIN 53 217) | 23 °C | [kg/m3] | 1030 - 1055 |
| Shelf-life | max. 23 °C | [month] | min. 6 |
| Flash point (PM) | [°C] | 32 | |
| Gel time1) | 100 °C | [min] | 30 - 50 |
| Pot life of impregnating resin with hardener by 10 % throughput of tank volume per week | unlimited | ||
| Test of effect of impregnating resin on enameled wires (LCIA, LCDA)2) | meets | ||
Tab. 2 Properties after cure
| Drying into depth3) | I. 1.1.1.8) 0. 1.1.1. |
|
| Curing of test specimen 140 °C | [h] | 2 |
| Electric strength3), 4) 23 °C 155 °C after 24 h immersion in water at 23 °C |
[kV/mm] | 70-80 60-70 30-40 |
| Volume resistivity3) 23 °C 155 °C po 7 dňoch uloženia vo vode 23 °C |
[Ω.m] | 1014 1011 1013 |
| Flexibility (mandrel test ø 3 mm)5) 23 °C | no cracks up to diameter to angle 180° | |
| Twisted coil test6) 23 °C 90 °C 155 °C |
[N] |
250 - 300 |
| Bundle test6) 23 °C 90 °C 155 °C |
[N] | 700 - 810 650 - 700 250 - 350 |
| Thermal endurance7), Test criterion: Bond strength 22 N (Helical coil) |
[°C] | 181 |
| Thermal endurance7), Test criterion: Breakdown voltage 1500 V (Twisted pairs)* |
[°C] | 228 |
1) DIN 16945 Verfahren A
2) STN 67 3150 čl. 11, met. B, after 60 min at 70 °C
3) DIN 46448 Blatt 1
4) Test specimens A2, cylindrical electrode diameter 6 mm
5) IEC Publication 464 - 2
6) STN IEC 61033
7) STN IEC 60216
8) Specimen appearance: hard, free of leaks and bubbles, surface smooth, non tacky
* UL File No.: E233982 measured on wires MW 35
Impregnating resins complied with tests done in American laboratory Underwriters Laboratories Inc.
Test protocol: UL E233982
Packing and storage
Impregnating resin is delivered in non-returnable, clean, for other products not used drums DG 55 with capacity 216,5 l, eventually in packages according to agreement between producer and client..
Impregnating resins are stored in tightly closed packages in dry ventilated warehouse by max. +23 °C, which complies with STN 65 0201.
