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. The efficiency of a 400-kVA, single-phase, 60-Hz transformer is 98.77% when delivering full-load current at 0.8 power factor, and 99.13%with half rated current at unity power fa
outline what three features you would add (choose the three that you feel would be most advantageous) to the 16 bit version of the processor in order to enhance its power.
Define instruction cycle and T-state Instruction cycle is defined, as the time needed completing the execution of an instruction. Machine cycle is defined as the time needed co
Why armature core in a DC machine is constructed with laminated steel instead of solid steel sheets
A battery having of 12 cells are divided in three group which each group having of four cells in series. The three groups are joined in parallel. The emf of every cell is 1.5V and
I would like to know the materials needed for electrostatic sprayer.
Explain graphic adapter and monitor. Video card changes digital output from the computer in an analog video signal and sends the signal by a cable to the monitor also termed a
Figure shows an isolated three-phase load supplied from a 33 kV/11 kV substation via a 30 km long three-phase 11 kV overhead line. The overhead line has the following series parame
(a) Design a passive high pass filter that has a maximally flat response with a 50 Ω resistive load. Assume that the cut-off frequency is 40 kHz and that at a frequency of 25 kHz,
Q. Show that any amplifier represented by the model of Figure of the text can also be represented by themore general hybridmodel of Figure. Evaluate the four parameters of the hybr
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