Which of the following is type of controlling torque method?

Spring control is the most common method of providing controlling torque in electrical instruments.

What is the purpose of controlling torque?

Controlling torque acts in the opposite direction to the deflecting torque. Moreover, in the absence of controlling torque, the pointer once deflected, would not return to zero position on the removal of the current. There are two methods of providing controlling torque in the instrument.

What is controlling and damping torque?

Damping force or Damping Torque: This force is necessary to bring the pointer to rest in its final deflected position quickly. Without such damping, the combination of deflecting torque and controlling torque makes the pointer to oscillate about its final deflected position for some time.

What type of controlling torque is used in energy meter?

In energy meter, there is no controlling torque, as the driving torque alone is enough to cause continuous revolution of the disc.

What is spring control method?

This is the most common method of providing controlling torque in electrical instruments. A spiral *hairspring made of some non-magnetic material like phosphor bronze is attached to the moving system of the instrument as shown in Fig. ( a).

What is damping torque & how it is classified?

The damping torque is proportional to the speed of rotation of the moving system, that is Tv = kv d dt θ Damping Torque. We have already seen that the moving system of the instrument will tend to move under the action of the deflecting torque.

Why is controlling torque necessary in an analog indicating instrument?

In a measuring instrument, the damping torque is necessary to bring the moving system to rest to indicate steady reflection in a reasonable short time.It exists only as long as the pointer is in motion.

How is deflection torque calculated?

The controlling torque is directly proportional to the angle of deflection of the coil. Control torque Ct =Cθ where, θ = deflection angle in radians and C = spring constant Nm /rad .

What is spring control?

What is meant by damping torque?

Damping torque or damping forces is the speed deviation of an electromechanical torque deviations of a machine while the angle deviation is called synchronizing torque [1]. If the damping force is too large, then the pointer will come to rest slowly and this is called as over damping.

What is the deflecting torque?

Deflecting torque: The torque needed to move the pointer over a calibrated scale is known as deflecting torque and it can overcome the inertia of the moving system, controlling torque and damping torque. The deflecting torque in the analog measurement device is proportional to the current through the coil.

What are the various methods for providing damping torque in an instrument?

There are four different ways of producing damping torque, these include air friction damping, fluid friction damping, eddy current damping, and electromagnetic damping.