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.
Interrupt Signals There are five interrupt signals in 8085 microprocessor. These signals are used to inter rut the current program under execution and transfer the ex
Two sine waves along with periods of 10 ms and 30 ms are added to generate a single waveform. A spectrum analyzer is utilized to examine the frequency contents of the waveform. Wha
Explain Lithography. Lithography - This is one of the processes which is carried out throughout manufacture of integrated circuits. Silica oxide (SiO 2 ) layer is thermally
Sing Flag If D7 ( bit left most bit) of accumulator (which some exceptions) is 1 as a result of any arithmetical or logical operations sign flag is set ( bit corresp
Explain the significance of the loss tangent of a dielectric material. The loss tangent contains a very small value for free space. For solid materials there tan δ = 0.003, tha
Inverters Inverter is a device which converts dc power into ac power at desired output voltage and frequency. Inverters are used in uninterruptible power supply hvdc tra
Calculate the Small Signal Voltage Gain a) Calculate the small signal voltage gain a v = v o /v i , input resistance R i , and output resistance Ro for the circuit below. A
Q. What is their relation with gain? What are the factors affecting frequency response of an amplifier? Some amplifiers should be "flat" across a band of frequencies. In other
Q. Explain Basic Control Systems? Electric energy is widely used in practice, because of the ease with which the system and device performance can be reliably controlled. One o
thermocouple
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