Series connected motor, Electrical Engineering

Assignment Help:

In this case, the armature is connected in series with the field coils. Thus
Ia  = If = I

 

1627_Series connected motor.png

 

 

911_Series connected motor 1.png

 

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.

336_Series connected motor 2.png

 

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 diverts
some 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.


Related Discussions:- Series connected motor

The central processing unit - stepper motor , The Central Processing Unit ...

The Central Processing Unit The  central processing  unit  is the brain of whole PLC.  The CPU  consist of a microprocessor memory  chip  and other  integrated circuits to con

Dsp, A pure sine wave with a frequency of 100Hz is sampled at 150Hz. At whi...

A pure sine wave with a frequency of 100Hz is sampled at 150Hz. At which one of the following frequencies would you expect an alias?

The operation of colpitts oscillator, Q. Explain with the help of a circuit...

Q. Explain with the help of a circuit diagram,the operation of COLPITTS OSCILLATOR. Oscillator is a circuit used to generate a.c voltage without a.c.input signal.The energy to

Mechanism of metal removal in electrochemical machining, What is the proces...

What is the process of metal removal in electrochemical machining? What are the basic functions of electrolyte in ECM? Illustrate the following key terms in electrochemical mach

Deviations from purchasing power parity, Q. Does the existence of non-trada...

Q. Does the existence of non-tradable goods allow for deviations from Purchasing Power Parity? Answer: Yes the continuation of non-tradable goods permits deviations from Purch

Transmission and distribution losses - electrical energy, Transmission And ...

Transmission And Distribution Losses - Electrical Energy Previously, you have learnt that there are inherent losses in transmission and distribution of electrical energy from

Ohm, what is ohm?

what is ohm?

Clampers., hint on clamping as a project topic

hint on clamping as a project topic

Off line ups system - power supplies , Off line UPS System Again the tw...

Off line UPS System Again the two  switches  are used in this  type of ups  as online  ups. The difference  is that  here  the main  static  switch  remains normally  ON and UP

Power, what is reactivecpower

what is reactivecpower

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd