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Old 01-08-2015, 11:54 AM   #1535 (permalink)
cts_casemod
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Slip angle, unfortunately, is not stationary as a PMDC. One can increase slip frequency, but this is somewhat equivalent to more powerful magnets on a BLDC only. There's not a lot to know here: The rotor is a secondary of a transformer, the stator is the primary. The larger the primary magnetic field (input voltage) and frequency difference between the rotor and stator (slip frequency or n) the larger the secondary current and hence the larger the flux, resulting in an increase in torque. With limits, because the rotor can saturate, basically creating a short circuit.

Regarding boost, in order for an inductor to "boost" the magnetic field must be collapsing (ie, input power removed). This is the opposite requirement to generate torque. Sure the motor can be used as a large inductor for boost purposes, but doing so while operating will only create drag and on case of an induction motor it will not generate useful magnetizing current for the rotor (The sum of the 3 phase currents going to the motor is 0A, disturbing this would generate an inbalance).

Paul, please have a look at this file:
https://www.rockwellautomation.com/r...ion_motors.pdf
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