Calculate motor efficiency, Electrical Engineering

1. A self excited shunt generator supplies a load of 12.5 kw at 125 volts. The field resistance is 25 ohms and the armature resistance is 0.2 ohms. The total voltage drop because of brush current and armature reaction at this load is 3 volts. Calculate the induced armature voltage.

2. A 6 pole lap-wound armature having 720 conductors, rotates in a field of 20.35 mWb. (a) If the induced current is 72 A, what is the torque developed by armature? (b) If the induced armature voltage is 410V, what is the motor speed?

3. A shunt motor runs at 1100 rpm at 230v and draws a line current of 40 A. The output power(at the shaft) is 10.8 h.p. The various losses are core loss, 200W: friction and windage loss 140W: electrical loss due to brush contact, 32W: stray load loss, 31W. The armature and field-current resistance are 0.2 ohms and 220 ohms respectively. Calculate (a) motor efficiency, (b) the speed if the output power is reduced by 50%.

4. A 4 pole motor is lap wound with 728 conductors and has a flux of 25 mWb per pole. The armature takes 50 A in current: the resultant demagnetizing effect due to armature reaction reduces the air gap flux by 5%. Calculate the developed torque.

5. One of three fuses protecting a 3-phase electric heater rated at 200kW, 600 V is removed so as to reduce the heat produced by the boiler. What power does the heater develop under these conditions?

 

Posted Date: 2/25/2013 1:06:11 AM | Location : United States







Related Discussions:- Calculate motor efficiency, Assignment Help, Ask Question on Calculate motor efficiency, Get Answer, Expert's Help, Calculate motor efficiency Discussions

Write discussion on Calculate motor efficiency
Your posts are moderated
Related Questions
Why are waveguides not used at low frequencies?

For Sign Flag  CP ( Call on plus ) CM (Call on minus ) Instruction CP call  the subroutine  from the  specified  memory  location if  sign flag is not set or reset( S=0)

Q.  Give suitable block diagram to explain the working of electronic multimeter. Sol. An electronic multimeter is a laboratory instrument which is capable of measurement of

Q. Show the procedure of Hex to Decimal Conversion? To convert from the Hex to the Decimal, multiply the value in each position by its hex weight and add each value. Using the

how started the use of complex variables in circuit analysis for the first time.

Consider the circuit of Figure (a) and obtain the complete solution for the voltage v C (t) across the 5-F capacitor and the voltage v x (t) across the 5- resistor.

ADC   Instruction This instruction is used to add the contents of any register of any register  memory location and carry  flag with the  contents of accumulator  and result  i

Schematic Symbols The junction gate field-effect transistor or JFET gate is sometimes drawn in the middle of the channel (in place of at the drain or source electrode as in t

What is the  use of latch signal on the AD0-AD15 bus in an 8086 system? Latch signal is used to load the data those are fetched from memory to bus.

What is programmable interrupt controller? The Programmable interrupt controller is used when several I/O devices transfer datausing interrupt and they are connected to the sam