How is armature torque calculated?
How is armature torque calculated?
The sum of the torques due to all armature conductors is known as gross or armature torque (Ta). Now i = Ia/A, B = φ/a where a is the x-sectional area of flux path per pole at radius r. Clearly, a = 2πrl/P. Hence torque in a d.c. motor is directly proportional to flux per pole and armature current.
What is armature torque and shaft torque?
Therefore, shaft torque (Tsh) is somewhat less than the torque developed in the armature. Thus, in the case of DC motors, the actual torque available at the shaft for doing useful mechanical work is known as Shaft Torque. It is called so because it is available on the shaft of the motor.
How is torque related to armature current?
armature current (Ta-Ia) This characteristic is also known as electrical characteristic. We know that torque is directly proportional to the product of armature current and field flux, Ta ∝ ɸ.
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. Equation (1) is the torque equation for DC machine.
How do you calculate armature EMF?
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.
What is the relation of N between EB flux?
Speed Control of DC Motors The speed of a DC motor is given by the relation N ∝ Eb/ϕ where Eb = V – Ia Ra. From the above equation it is clear that the speed of DC motors can be controlled; 1. By varying flux per pole ϕ. This is known as flux or field control method.
In which winding less EMF is generating?
Detailed Solution
| Lap Winding | Wave Winding |
|---|---|
| Another name of lap winding is multiple winding otherwise parallel winding | Another name of wave winding is series winding |
| The emf of lap winding is less | The emf of wave winding is more. |
| The efficiency of the lap winding is less | The efficiency of the wave winding is high. |
How does armature current and motor torque relate to DC motor?
The increase in the torque on the motor shaft results in the linear increase in the armature current. It is also shown in the equation (8) from the previous tutorial. The current function I, depending on the torque M, shows that more current flowing through the motor will produce a higher torque.
What is the relation between torque and armature current in DC motor?
Since in the case of DC shunt motor, the flux per pole is considered to be constant. Hence Torque is proportional to the armature current. With the increase in armature load current, the torque increases, which gives a linear relationship. The obtained characteristic is a straight line passing through the origin O.
For which DC motor torque is proportional to the armature current?
dc shunt motors
For DC Machine, torque is directly proportional to armature current and flux. In dc shunt motors, flux is constant (not dependent on armature current). Hence torque is proportional to armature current.
What is torque in DC generator?
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.
What is the relation between armature torque and armature current in dc series motor?
The torque in case of a dc series motor is proportional to the square of the armature current. This relation is parabolic in nature as shown in the figure. As load increases, armature current increases and torque produced increases proportional to the square of the armature current up to a particular limitation.
What is armature torque in DC motor?
The torque is measured in Newton-meters (Nm). In a DC motor, a circumferential force (F) at a distance r which is the radius of the armature is acted on each conductor, tending to rotate the armature. The sum of the torques due to all the armature conductors is known as armature torque (τ a ).
What are the advantages of armature control?
Constant field current and torque: With the armature control method, the field current and torque levels remain constant throughout the application. Regardless of the speed of the motor, you can rely on these factors.
How is torque produced in the armature directly proportional to flux?
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. Moreover, the direction of electromagnetic torque developed in the armature depends upon the current in armature conductors.
What is an armature in a generator?
An armature is defined as the component of the electric machine (i.e. a motor or generator) that carries alternating current (AC). The armature conducts AC even on DC ( Direct Current) machines via the commutator (which periodically reverses current direction) or due to electronic commutation, (e.g. in a brushless DC motor ).
