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. If an antenna has an available noise power of 1.6 × 10 -15 W in a 1-MHz bandwidth, find the antenna temperature.
1- Use 4-to-16 decoder and some residue gates to recognize the following functions F1(A,B,C)= S(1,2,4,5,7) F2(A,B,C,D)= S(1,2,4,5,7,10,12,14,15) F3(A,B,C,D,E)= S(1,2,4,5,7,10,12,1
block diagram of digital control system and explain each block
Q. For an n-channel JFET with V A = 350 V, I DSS = 10 mA, and V P = 3V, find V DS that will cause i D = 11 mA when v GS = 0.
Holography In 1947, Denis Gabor invented a different type of photography, know as holography. He named this new technique wave front construction. According to this technique
Q. IllustrateCommon base configuration? Common base configuration: In this circuit the base is common to both input and the output.Such a configuration is also known as groun
BLOCK DIAGRAM OF DIGITAL CONTROL OF ELECTRIC DRIVES
what ternary alloy, composition and binary substrate can be used for an LED at 1.55 µm optical fiber windo
Knowledge of science and engineering fundamentals Knowledge of basic science and engineering fundamentals is necessary for engineers to develop solution to any complex problem
Explain the Synchronous Machines? A synchronous machine, unlike an induction (or asynchronous) machine, only develops torque at a fixed, so called, synchronous speed - n s whi
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