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ECE 432 - Variable Speed Drives

Assignment 1: Drive FundamentalsDue Date: Friday, January 29, 2016, 3:00pm

Submission Box on the 2nd Floor of ECERF

Question I

Name the control regions for variable speed drives, above and below rated speed. (4 marks)

Question II

Name the two circuit input variables which limit the operation of machines under steady state conditions,

irrespective of speed. (4 marks)

Question III

An induction motor is operated with a drive and controlled to maintain rated flux. The motor has 4 poles,

rated frequency is 60 Hz and rated torque of 50 N·m occurs at 1740 rpm.

1) Calculate the rated slip speed in rpm and slip frequency in electrical radians per second. (4 marks)

2) Rated torque is required at 1190 rpm, what supply frequency is needed? (4 marks)

3) 25 N·m torque is required at 1170 rpm, what supply frequency is needed? (4 marks)

4) The motor operates at 864 rpm with supply frequency 30 Hz. What is the torque? (4 marks)