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.
The Series Resistance rule
Magnetic circuits To see how this is used in practice, consider a coil of N turns wound onto a closed ring shaped former with a very high (note: r (steel) = 200
What do you understand by solar water heating and discuss different kind of solar water heating based on collector-storage and circulation type. Discuss integrated collector - s
Q. What are the different types of coupling in amplifiers? The coupling between stages of amplifications may also be used to classify amplifiers. There are four main groups: di
Discuss all the five software interrupt instructions. The INTEL family microprocessor consist of software interrupts INT, INT0, INT3 and BOUND and IRET. Out of all these five
Evaluate the form factor: For the saw tooth wave illustrated in Figure, find out the form factor. Figure: Saw Tooth Wave Solution Time period of given wave i
Q. What is Frequency Translation and Product Modulation? The basic operation needed to build modulators is the multiplication of two signals. Whenever sinusoids are multiplied,
Metering Technologies An electric meter or energy meter is a device in which measures the amount of electrical energy supplied to customers of an electric supply company. Elec
what is digital signal
Geographic Information System: Geographic Information System (GIS) is a computer system capable of assembling, manipulating, storing, and displaying geographically referenced
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