This question relates mainly to the sixth objective in the course specification.
A 22kW, 440V, 50Hz, 4-pole cage induction motor is part of an adjustable speed drive system. At the base voltage and frequency, the full-load slip is 0.05. It can be assumed that the torque-speed characteristic of the motor is linear in the slip frequency range from -5 Hz to 5 Hz.
Combined moment of inertia of motor and load = 12kgm2.
Load torque in Nm = 5ω where ω is in rad/s.
The steady state operating speed ranges from 900r/min to 1400r/min.
Acceleration is required to be constant at 30rad/s2 and deceleration is required to be constant at 60 rad/s2.
The drive consists of a voltage source inverter with a three-phase diode rectifier at the front end. The supply voltage may be assumed to be 440V.
Estimate-
(a) steady state-slip when speed is 1400r/min.
(b) steady state slip when speed is 900r/min.
(c) required electromagnetic torque during acceleration and during deceleration.
(d) maximum DC input current to the inverter during acceleration (assume efficiency of motorinverter combination is 91%).
(e) acceleration time from zero speed to 1400r/min.
Attachment:- Assignment.pdf