Answer / nilkanth tailor

COZ, TORQUE IS DIRECTLY PROPORTIONAL TO THE SQUARE OF THE
CURRENT...SO THAT THIER IS VER HIGH CURRENT PRODUCE IN THE
STARTING OF DC SERIES MOTOR...AND IT IS DIFFICULT TO
CONTROL HIGH CUURENT...SO GENERALLY D.C. SERIES MOTOR
GENERALLY USEB IN TRAIN...CAUSE TRAIN REQUIRE HIGH STARTING
TORQUE...DUE TO HEAVY LOAD

Answer / naveen

Torque is proportional to flux and current.

reason why starting torque is high in series motor only is:
in DC series motor, flux is also proportional to current since the field winding is series with DC motor.

and the reason why its high in start is :
in starting back emf is 0 . current=(V-Ef)/R when Ef is 0 current attains high value which decreases as the speed of motor increases and thus the Ef.

Answer / ubendran mv

In SERIES MOTORS, the field windings are connected in
series with the armature coil. The field strength varies
with changes in armature current. When its speed is reduced
by a load, the series motor develops greater torque. Its
starting torque is greater than other types of dc motors.
Its speed varies widely between full-load and no-load.
Unloaded operation of large machines is dangerous.

what is cogging and crawling

0 Answers   Suzlon,

---

there is a line fault some where on the ove head distribution line. how will i locate the fault for clearing it? ofcourse i have to megger the line but what information makes me clear that the fault is in that section of the line?

2 Answers  

---

What will happen to the speed of synchronous machine subjected beyond the pull out torque? Are the behavior shown by rotor remains same for both the alternator and motor?

1 Answers  

---

how can we phase identification in a distribution line,how we recognise that which phase is coming for a house hold connection.help me............

0 Answers  

---

What is the Basic Difference bitween Long Shunt Connection and Short Shunt Connection in DC Generator?

0 Answers  

---

Why Earthin is not required in Xformer primary side when it is in Star / star?

2 Answers  

---

what is vfd?

2 Answers  

---

can alternators work at leading power factor?

2 Answers  

---

Write the force balance equation of ideal spring element.

0 Answers  

---

The current though a branch in a linear network is 2A when the input voltage is 10 volts. If the voltage is reduced to 1 volt, and the polarity is reversed, what is the current flowing through the branch ?

2 Answers  

---

can induction motor run over the rated speed ?

12 Answers   ACC,

---

WHAT SHOULD BE THE MINIMUM IR VALUE FOR LV (380V) CABLES ACCORDING TO IEC/IEEE.

3 Answers  

---