Heat is generally bad for efficiency and system performance
Electric motors
Heat affects
R (increases)
Flux (decreases)
Torque (decreases)
Stored heat (increases)
High internal heat melts insulation causing short circuit
Motor selection
Datasheet
Maxon motors
Continuous = rated
Same power but different models
Different voltage and current
Different efficiency
Nominal voltage → Nominal power
No load speed → speed at internal load / no external load current
Nominal speed → speed at rated, continuous, nominal torque / rated power
Servo motor → feedback maintains constant speed at variable torque (in the operating region) | increasing voltage gives more power to the motor to maintain speed
Max continuous torque → torque at which the motor can theoretically work for ever (only other factors like lifetime ) / Qin=Qout
Operation conditions affects performance and reduce lifetime: cool → torque 👆 | hot → torque 👇
Allow for motor cooling (housing)
Current protection and temperature protection → present in motor controller for preventing damage for expensive motor and components (they detect current and time to estimate heat or measure heat directly)
Expensive drives = protection
RMS torque should be equal to max continuous torque (don’t overestimate) / there is an allowance
Max efficiency at nominal operating point
High thermal time constant is good
High load = isolate motor shaft from load shaft
Continuous operation vs. short term operation (thermal time constant)
