Eee118 Ch10 Final

25 pages
33 views

Please download to get full document.

View again

of 25
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Share
Description
1/7/2013 EEE 118: Energy Conversion Dr. Mongkol Konghirun Department of Electrical Engineering King Mongkut’s University of Technology Thonburi Chapter 10 Single-Phase And SpecialPurpose Motors 1 1/7/2013 10.1 The Universal Motor The Universal Motor The universal motor is essentially the series or shunt DC motor. However, it can be operated on a single-phase AC power source. Recall from Chapter 8: τind = KφIA …(8-49) When the polarity of the voltage applied to a shunt or series DC motor
Tags
Transcript
  1/7/20131 EEE 118: Energy Conversion Dr. Mongkol KonghirunDepartment of Electrical EngineeringKing Mongkut’s University of Technology Thonburi Chapter 10 Single-Phase And Special-Purpose Motors  1/7/20132 10.1 The Universal Motor 4 The Universal Motor The universal motor is essentially the series orshunt DC motor. However, it can be operatedon a single-phase AC power source.Recall from Chapter 8: τ ind = K  φ I  A  …(8-49)When the polarity of the voltage applied to ashunt or series DC motor is reversed, bothdirection of field flux ( φ ) and the direction of armature current (I  A  ) reverse, and resultinginduced torque continues in the samedirection as before  1/7/20133 5 Torque-Speed Characteristic The torque-speed characteristic of a universalmotor is different from one of the samemachine operating from DC voltage for tworeasons:1. The armature and field windings have quitelarge reactance (as a function of frequency).So, the voltage drop across these reactancesare large. Thus, the E  A  = K  φω is smaller for agiven input voltage. Then, the motor speed ω is slower for a given I  A  and τ ind .2. The peak voltage of an AC system is √ 2times its RMS value. The magnetic saturationcould occur near the peak current, loweringthe magnetic flux of the motor for a givencurrent. The induced torque is partiallyreduced for a given speed. 6  Applications of UniversalMotors The universal motor has the sharply drooping torque-speedcharacteristic of a DC series motor (E  A  significantlyreduced), so it is not suitable for constant-speedapplications.However, it is compact, light weight and gives moretorque/amp than any other single-phase motor.Typical applications for this motor are vacuum cleaners,drills, similar portable tools, and kitchen appliances.  1/7/20134 7 Speed Control of UniversalMotors Similar to the DC series motor, the speed of universalmotor is increased when the RMS input voltage isincreased. 10.2 Introduction to Single-PhaseInduction Motors
Related Search
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks