Physical effects of gross overheating on epoxy-mica insulation systems
Physical effects of gross overheating on epoxy-mica insulation systems
(OP)
I am interested in learning about what we might expect if a Roebel bar is subject to excess temperature at some unknown value below the melting point of copper.
The few things I know:
Epoxy resin is 'thermosetting" rather than "thermoplastic". Therefore, it can get brittle and crack, but should not get soft and flow. Therefore, we would not expect conductors to move during a coil failure event unless the epoxy resin was cracked. Would you agree?
I think there may be a lot of experience here from people that burn coils out of motors. What condition do you find coils in that have been burnt out? Does the coil soften or does it shrink due to off-gassing? (I'm thinking it shrinks).
At what temperature does the epoxy begin to off-gas?
The few things I know:
Epoxy resin is 'thermosetting" rather than "thermoplastic". Therefore, it can get brittle and crack, but should not get soft and flow. Therefore, we would not expect conductors to move during a coil failure event unless the epoxy resin was cracked. Would you agree?
I think there may be a lot of experience here from people that burn coils out of motors. What condition do you find coils in that have been burnt out? Does the coil soften or does it shrink due to off-gassing? (I'm thinking it shrinks).
At what temperature does the epoxy begin to off-gas?
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(2B)+(2B)' ?





RE: Physical effects of gross overheating on epoxy-mica insulation systems
RE: Physical effects of gross overheating on epoxy-mica insulation systems
When it comes to how laminates of materials with differing CTE hold-up to thermocylcling, the layer thickness is the main factor. Thin layers a far more durable that thick layers.