3.16.4
Newer varnish formulations cure in minutes rather than hours. In the past, conventional varnishes required preheat temperatures of about 300°F (149°C) and bake temperatures of 350°F (177°C), whereas newer catalyzed varnishes have preheat temperatures in the range of 150 to 200°F (65 to 93°C) and bake temperatures just slightly higher. As a result of these lower cure temperatures, utility costs are also considerably reduced.
A generalized comparison of the energy cost for processing parts using a dip-and-bake resin and two available chemically cured trickle resins is shown in Tables 3.18 and 3.19. Identical 48-frame stator-coil assemblies were used in the
TABLE 3.18 Energy Costs of Using Three Varnish Resins
| Dip and bake | Trickle, 100:3 | Trickle,100:1 | |||||
| Gas cost, | Operating, | Heat-up, | Operating, | Heat-up, | Operating, | Heat-up, | |
| City | $/therm* | $/h | $ | $/h | $ | $/h | $ |
| Milwaukee | 0.49 | 1.45 | 2.52 | 0.60 | 0.46 | 0.34 | 0.19 |
| St. Louis | 0.49 | 1.45 | 2.52 | 0.60 | 0.46 | 0.34 | 0.19 |
| Dallas | 0.40 | 1.18 | 2.05 | 0.49 | 0.38 | 0.28 | 0.16 |
| Charlotte | 0.55 | 1.63 | 2.82 | 0.68 | 0.52 | 0.39 | 0.22 |
| Nashville | 0.33 | 0.98 | 1.70 | 0.41 | 0.31 | 0.23 | 0.13 |
| * Therm = | 100,000 BTU. All prices as | of May 1995 with taxes included. | |||||
TABLE 3.19 Annual Energy Operating Costs with Three Varnish Resins
| City | Dip and bake | Trickle, 100:3 | Trickle,100:1 |
| Milwaukee | $6490 | $2665 | $1441 |
| St. Louis | 6490 | 2565 | 1441 |
| Dallas | 5337 | 2096 | 1183 |
| Charlotte | 7370 | 2907 | 1647 |
| Nashville | 4432 | 1752 | 972 |
| Average cost | $6024 | $2377 | $1377 |
| Average cost | $0.006 | $0.002 | $0.001 |
| per stator |
comparison and some data were estimated. The data are not exact and are for comparison purposes only.
