Typical ranges for motors are -50 to +150C. This means that the motor supplier will use materials that are rated above these to achieve a safety factor. If there is an encoder in the system the  limits may change from operation at 0C to 80C due to limits on the encoder and it depends on where it is in the system. Bearings area is also limited by colder temperatures. Electrical insulation systems and magnets can be chosen to operate over 200C if the rest of the mechanical systems can handle this temperature.