The series connection of armature and field windings (Figure 3.15(a)) means that the field flux is directly proportional to the armature current, and the torque is therefore proportional to the square of the current.
How is torque related to flux and armature current?
We know that torque is directly proportional to the product of armature current and field flux, Ta ∝ ɸ. … In DC series motors, field winding is connected in series with the armature, i.e. Ia = If. Therefore, before magnetic saturation of the field, flux ɸ is directly proportional to Ia.
What is the relationship between speed and torque regulation in DC shunt motors?
For dc series motor the torque and speed are inversely proportional to each other and in dc shunt motor the speed is independent of the torque as speed decrease very little for large increase in torque so dc shunt motor is also called constant speed motor.
What is the formula of armature torque of DC motor?
Ka = (PZ/2πa). Since Ka depends upon the constructional design of DC Motor or generator, it is known as armature constant. Here P is number of poles, Z is total number of armature conductor and ‘a’ is the number of parallel paths in armature.
How is torque calculated in DC shunt motor?
Where n is the speed in (rps). For a particular DC Motor, the number of poles (P) and the number of conductors per parallel path (Z/A) are constant. Thus, from the above equation (5) it is clear that the torque produced in the armature is directly proportional to the flux per pole and the armature current.
Is current directly proportional to torque?
Current is directly proportional to torque, i need the equation supporting this statement. Join ResearchGate to ask questions, get input, and advance your work.
Is current proportional to torque?
torque is proportional to current pulled.
What is the principle of DC shunt motor?
Construction and Working Principle
The working principle of a DC Shunt Motor is, whenever a DC motor is turned ON, then DC flows throughout stator as well as the rotor. This current flow will generate two fields namely pole as well as the armature.
Why DC shunt motor is constant speed?
If the load on the motor increases armature speed reduces and thereby cause a reduction in the back emf. … Hence, a DC shunt motor always maintains a constant speed. Under no load condition, the back emf becomes nearly equal to the applied voltage.
What is relation between speed and torque?
Torque is the rotational equivalence of linear force. Speed measures the distance covered in unit time. The relation between torque and speed are inversely proportional to each other. The torque of a rotating object can be mathematically written as the ratio of power and angular velocity.
What is the torque of a DC motor?
Torque equation of a DC motor
When armature conductors of a DC motor carry current in the presence of stator field flux, a mechanical torque is developed between the armature and the stator. Torque is given by the product of the force and the radius at which this force acts.
Which is proportional to the torque in dc motor?
1 Answer. The torque, in a DC series motor is proportional to the square of the armature current.
What is source of torque in dc motor?
The brushed DC electric motor generates torque directly from DC power supplied to the motor by using internal commutation, stationary magnets (permanent or electromagnets), and rotating electromagnets.
Do DC motors have constant torque?
DC motors can develop a constant torque over a wide speed range. For a DC motor : Torque is proportional to armature current – this means controlling torque requires simply controlling the motor DC current – easily achieved with a simple DC drive.
How do you increase the torque of a DC motor?
Any DC motor will experience a decrease in speed when a load is applied, which causes the back EMF to decrease. The reduction in back EMF increases the net voltage, since the supply voltage remains constant. The net voltage increase causes the armature current to increase, which increases the motor torque.
WHAT IS A in DC generator EMF equation?
As the armature rotates, a voltage is generated in its coils. In the case of a generator, the emf of rotation is called the Generated emf or Armature emf and is denoted as Er = Eg. In the case of a motor, the emf of rotation is known as Back emf or Counter emf and represented as Er = Eb.