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!
In this case, the armature is connected in series with the field coils. Thus Ia = If = I
NB. At starting, the back emf is zero (because the motor is initially stationary) and hence the current is very large (limited only by the field and armature resistances). Hence the starting torque will be extremely large and if no load is applied (so that the torque requirement is small) the motor will accelerate rapidly to dangerously high speeds. A series connected motor must be started with a mechanical load attached to prevent the speed at start up rising to damaging speeds.Note that saturation of the magnetic material in the motor can occur at high currents and then the flux generated by the field coils becomes independent of current. This causes the characteristics to become similar to that of a shunt wound motor that also has an approximately constant field flux.
The series motor gives a high starting torque (proportional to 1/I2 ), 2.5 to 3 times the full load (rated) torque) but it falls rapidly as the speed increases. Applications: heavy duty, with intermittent starting under conditions where a mechanical load is always present - e.g. traction, cranes, hoists. etc
The speed of a series wound motor may be controlled by the addition of a resistor in parallel with the field coil. This divertssome of the current away from the field coil, reducing the field strength and hence the back emf at a given speed. The additional resistor is called a 'diverter'. The speed must increase to compensate this reduction in back emf. . Hence a reduction in the diverter resistance reduces the field strength and increases the speed of the motor.
Revenue Protection and Technology Interventions in Metering The power supply industry has reached an impasse where urgent steps are needed to improve the financial health of t
Q. Write a brief note on common drain amplifier Since voltage at the gate-drain is more easily determined than that of the voltage at gate-source, the voltage source in the inp
Explain the properties and application of glass. Glass: Ordinary glass is a fine insulator but is too brittle to be used for anything although scientific instrument parts, accu
Q. Show the r’s Complement? Step1- get the (r-1)'s complement Step 2- add 1 to the result ex. 935 10 9 9 9
Explain the working principle, Surface finish, material removal, accuracy,advantages and application of Electrochemical Grinding(ECG). (a) In electro chemical machining of pure
Q. Describe in detail the construction and working of analog type storage oscilloscope. Explain the principle of secondary emission. Analog Storage Oscilloscopes: Storage o
A wound-rotor induction machine, driven by a dc motor whose speed can be controlled, is operated as a frequency changer. The three-phase stator winding of the induction machine is
Prepayment Meters Usage of prepayment meters will extensively improve the revenue collection of the utilities. There are a number of ways in that prepayment assures revenue pr
What is the value of a resistor marked as 47KK?
(a) Design a 6-bit R-2 R ladder D/A converter. (b) For V ref = 10 V, find the maximum output voltage. (c) Determine the output voltage increment. (d) If the output voltag
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