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.
Q. A practical current source is represented by an ideal current source of 200 mA along with a shunt internal source resistance of 12 k. Determine the percentage drop in load curr
examples in building electric helicopter using cardboard, balsa wood, scotch tape, glue, binder clips, rubber bands, rubber stoppers, etc. attached to a 12v power supply
Role of ERCs: A National Electricity Policy is one of the key instruments for providing policy guidance to the Electricity Regulatory Commissions in discharge of their functio
Determine currents in the circuits: Determine currents I 1 and I 2 in the given circuits by applying KVL. Solution We apply KVL for first loop : 10 = 1 I 1 + 1
Q. What do you mean by Load factor? The two components of electric service are demand and energy. Demand is the maximum level of real power which the electric utility must supp
how to compute the fourier series expansion of a rectangular pulse train
Explain CWD instructions in 8086 family with example and their effect on flag. Convert signed word to signed double word: CWD instruction enlarges the sign bit of a word int
Importance: The transistor is the main active component in practically all current electronics, and is considered through many to be one of the greatest inventions of the 20 t
Q. Show NPN Common Collector Amplifier? The common collector amplifier, often called an emitter follower since its output is taken from the emitter resistor, is useful as
Given S(F) = A'B +'C'D + C'D +'A'B + 'A B + 'A 'C + 'A D + 'A C A. DRAW A MINIMIZED CIRCUIT USING ONLY OR AND NOT GATES (2 input gates) B. WRITE THE WIRE LIST Example of a
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