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.
Surge Current It is the maximum admissible peak value of a sinusoidal half cycle of 10 ms duration at a frequency of 50Hz. The value is specified at a given junction tem
role of trigger circuit in cro
Q. For the circuit shown in Figure, determine v out (t).
Assignment 2: FIR Filters in Audio Processing This assignment will focus on the filtering of audio signals using FIR filters. Audio signal processing uses many types of digital f
Mode 2 In this mode transistor gets turned off by the negative output of PWM current flows through inductance L diode D then divide into two parts one flows through
Consider an electromagnet, as shown in Figure, which is used to support a solid piece of steel and is excited by a coil of N = 1000 turns carrying a current i = 1.5 A. The cross-se
A uniform quantizer is said to have 16 levels, and hence is called a midriser. The saturation levels are to correspond to extreme values of the message of 1 V ≤ f(t) ≤ 17 V. Find
Illustrate the conventional representations of the following guide to the selection of Fits: (i) Slack Running Fit (ii) Loose Running Fit (iii) Easy Running Fit (iv) No
Q. Two coupled synchronous machines are used as a motor-generator set to link a 25-Hz system to a 60-Hz system. Find the three highest speeds at which this linkage would be possibl
Explain the working of an npn transistor. Working of npn transistor: In an npn transistor is demonstrated in the figure. The emitter base junction is forward biased whereas
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