Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
A 4- pole DC motor is known to have an armature resistance of 0.5 Ω, and is operated as a separately excited motor.
(a) When the motor is connected to a 250V DC supply with no external mechanical load and with rated field current, it runs at a speed of 1488 rpm with an armature current of 4A. Calculate the no load rotational losses under these conditions.
(b) The motor is now mechanically loaded until the armature current reaches 40A, under which conditions the DC supply voltage sags to 245V. Calculate the motor speed if the field current is unchanged.
(c) Assuming that the motor rotational losses vary proportionally with speed, calculate the motor efficiency under the load condition of (b).
(d) The motor field current is now accidentally set to half rated value. Calculate the DC supply voltage that is required to return to the same no load operating conditions of part (a)
(HINT: remember that the rotational power losses must stay the same if the speed is unchanged).
(e) Discuss the two possible ways of achieving variable speed operation for a DC machine. Show the torque speed characteristics of a DC motor operating under both these types of speed control strategies, and discuss how they relate to the concepts of the "constant torque" and "constant power" regions of variable speed operation. Discuss the advantages and disadvantages of each speed control strategy.
a body of mass 5kg moves with an acceleration of 20m/s calculate the force
what is feathering system in turbo prop type aircraft
case study of thermal stresses and composite bar
Holonic Manufacturing System Holonic manufacturing implies a highly distributive organization of the manufacturing systems. Intelligence is distributed between the individual e
Example of Alteration of Position and Reference Line Method: Sketch the projections of a pentagonal prism edge of the base 50 millimeter long and height 90 millimeter, the axi
Describe Mould Surface Coating? Mould surfaces are coated (after the pattern is drawn out) with certain materials possessing high refractoriness. It eliminates the poss
a) An epicyclic gear have three wheels A, B and C. Wheel A has 72 internal teeth, wheel C has 32 external teeth. The wheel B gears with both A and C is carried on an arm which move
how to draw circuits using cascade
Draw schematic diagram of a position control system using armature controlled DC Servo motor. Graph the signal flow graph and hence calculate the closed loop transfer function.
torque
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd