No it wasn't, it was the safety switch for the cover. A lever on the cover depresses the switch when closed "Properly", which totally explains why it wouldn't reset. Still, thanks for the speedy reply.
I must remember to think before asking stupid questions.
I must remember to think before...
Even with the power disconnected. If you hold the trip switch in reset position, motor starts and runs perfectly until you release the trip switch (which is inside the switch panel, not accessible without dismanteling the switch unit). No signs of excessive heat, no bare wires, no burning...