Speed control of dc series motor - motor control , Electrical Engineering

Speed Control of DC Series Motor

A half  wave  circuit  for the  speed  control of DC  series motor is  shown in figure and corresponding wave from  is shown  in figure  consists  diac  and diode  to give the  triggering pulses to the SCR. Here SCR  is used to  control the armature voltage  of the DC motor.  By varying R2 firing angle α can be  controlled  of SCR. During the positive  half  cycle of input  ac voltage capacitor C will through R1 and R2.

SCR will get  turned  on when the  capacitor voltage Vc is equal  to the addition  of back emf Eb  of motor  and break over voltage VBO of the diac. By  varying  the resistance R2 the charging  time of  capacitor (r= R2C)  hence the speed of motor can be controlled. Basically it is  the armature voltage control method. In case  when SCR  is not conducting the  armature voltage will be there due to  the residual flux which  is approximate proportional  to the speed .

Due to  the fluctuation  in load will results the  change  in speed of motor and according  back emf of the motor will change. Since  the break over voltage of  diac is constant and back emf is varying  means the difference of Vc and ( VBO + EB) may increase or decrease as EB is increased or decreased respectively. The  firing  of SCR  depends on this difference. As  a results  the average dc voltage  across  the armature will change  and speed  of motor  can control  accordingly.

 

Posted Date: 4/3/2013 2:15:27 AM | Location : United States







Related Discussions:- Speed control of dc series motor - motor control , Assignment Help, Ask Question on Speed control of dc series motor - motor control , Get Answer, Expert's Help, Speed control of dc series motor - motor control Discussions

Write discussion on Speed control of dc series motor - motor control
Your posts are moderated
Related Questions
Compute the efficiency of the transformer of Example corresponding to (a) full load, 0.8 power factor lagging, and (b) one-half load, 0.6 power factor lagging, given that the input

Conditional Jumps The most  important  part of  programming is its  decision making capability. Which is  normally  provided  by statements  like if  then else in high level

Diode current: Zener region: when the reverse biased voltage is increase to a very high value then a point is reached where will is suddenly going a very high value. Th

Illustrate the construction and working of:- (i) Pressure Thermometer (ii) Selective Radiation Pyrometer (iii) Thermistor (iv) Laws of Thermocouple

Power Control A chopper converts  fixed  de input voltage to a controllable dc output voltage. It is  the single  stage dc to dc conversion device. It is a high  speed  on/ of

Q. Explain Crystal Oscillator The frequency of a crystal-controlled oscillator is held constant to a high degree of accuracy by the use of a quartz crystal. The frequency depen

Direct and Indirect Semiconductors 1) In a common quantitative calculation of band structures, the wave function of a single electron traveling by a perfectly periodic lattice


Q. Draw and explain the circuit of Wein bridge oscillator. Obtain the expressions for the (i) frequency of oscillation and (ii) condition for oscillation. Will oscillat

Explain DAA instruction. DAA: The DAA instruction follows the instruction ADC or ADD to adjust the result in a BCD result. The DAA instruction performs only with the AL registe