A three-phase, six-pole, squirrel-cage induction motor is to be controlled by terminal voltage variation using pairs of inverse-parallel thyristors in the supply lines with symmetrical phase-angle triggering. The motor is rated at 50 kW, 240 V, 50 Hz. If it operates at a full-load efficiency of 0.9 p.u. and power factor 0.85. Calculate the rms current rating and maximum voltage rating required of the thyristors. The motor drives a fan load characterised by the relation T, = kw?, where T, the shaft torque is and w is the motor speed. Operation is required to give full load at full speed; which corresponds to 5 % slip, and at three quarters of the full speed. What approximate reduction of motor power is required (compared with full-load, full-speed operation) in order to realise operation at 750 rpm? If the motor operates at full voltage at upper speed, calculate, approx- imately, the voltage required at the lower speed. Explain and estimate the change of thyristor firing-angle necessary to obtain the required change of voltage.

A three-phase, six-pole, squirrel-cage induction motor is to be controlled by terminal voltage variation using pairs of inverse-parallel thyristors in the supply lines with symmetrical phase-angle triggering. The motor is rated at 50 kW, 240 V, 50 Hz. If it operates at a full-load efficiency of 0.9 p.u. and power factor 0.85. Calculate the rms current rating and maximum voltage rating required of the thyristors. The motor drives a fan load characterised by the relation T, = kw?, where T, the shaft torque is and w is the motor speed. Operation is required to give full load at full speed; which corresponds to 5 % slip, and at three quarters of the full speed. What approximate reduction of motor power is required (compared with full-load, full-speed operation) in order to realise operation at 750 rpm? If the motor operates at full voltage at upper speed, calculate, approx- imately, the voltage required at the lower speed. Explain and estimate the change of thyristor firing-angle necessary to obtain the required change of voltage.

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

See similar textbooks

Similar questions

3. Which of the following statements about the use of structural steel as an equipment grounding conductor(EGC) in an AC system is correct?A. Structural steel isn't allowed for use as an EGC.B. Structural steel can be used as an EGC bonding jumper between panelboards.C. Structural steel must have an EGC bonding jumper every three feet of structure.D. Structural steel can be used as an EGC when it's bonded at both ends.
I need the answer as soon as possible
Question Completion Status: Click Submit to complete this assessment. Question 8 What do you do to an asynchronous counter to let it count froms14 to 0? (Handwriting solution is needed: include this in your pdf file) Click Submit to complete this asseESment,
Choose the correct answer and show your solution. *Kindly provide a COMPLETE and CLEAR solution* (Answer should be typewritten) *Please answer it ASAP if you can
The contractor is controlled by?
The wording that I am running into with questions such as "The number of conductors required to be installed between three-way and four-way switches is " is confusing. The text is not expalining this in a way that I am understanding anything other than grounding conductor, which is optional unless I am using a metal box. So what type of "conductor" is beng discussed?
Complete the following text with words Pt100 sensors are a specific type of _____(1) detector. The most important characteristic of Pt100 elements is that they are made of _____(2) with an electrical resistance of _____(3) ohms at a temperature of ______(4) °C and temperature coefficient ____(5). It is by far the most common type of RTD sensor. The other materials with which RTDs are built are: ___(6), _____(7), ______(8). The most recommended conditioning method is reading at _____(9). Typically, a _____(10) behavior of the Resistance-Temperature relationship can be assumed.
Please answer quickly. 17. The filament of incandescent lamp is usually made of: a. copper b. silver c. aluminum d. tungsten 18. A current measuring instrument can be modified to measure voltages by: a. using thicker wire in the coil b. using a high resistance shunt c. adding resistance in series d. adding resistance in parallel 21. "When two power sources are connected in a series-aiding configuration, the output voltage equals the _____________" a. supply with the highest voltage b. supply with the lowest voltage c. difference of the two supplies d. sum of the two supplies
I need the answer at 20 minute.