The correct answer is: A. D.C. shunt motor
A D.C. shunt motor is a type of electric motor that uses direct current (DC) to power its armature. The armature is the rotating part of the motor that converts electrical energy into mechanical energy. The shunt motor is most suitable for signalling devices and many kinds of timers because it has a constant speed regardless of the load. This makes it ideal for applications where a consistent speed is required, such as in clocks and timers.
A D.C. series motor is a type of electric motor that uses direct current (DC) to power its armature. The armature is the rotating part of the motor that converts electrical energy into mechanical energy. The series motor is not suitable for signalling devices and many kinds of timers because its speed varies with the load. This means that the speed of the motor will change depending on how much work it is doing. This can be a problem in applications where a consistent speed is required, such as in clocks and timers.
An induction motor is a type of electric motor that uses alternating current (AC) to power its armature. The armature is the rotating part of the motor that converts electrical energy into mechanical energy. The induction motor is not suitable for signalling devices and many kinds of timers because it has a variable speed. This means that the speed of the motor will change depending on the load. This can be a problem in applications where a consistent speed is required, such as in clocks and timers.
A reluctance motor is a type of electric motor that uses the principle of reluctance to produce torque. Reluctance is the opposition to the flow of magnetic flux. The reluctance motor is not suitable for signalling devices and many kinds of timers because it has a variable speed. This means that the speed of the motor will change depending on the load. This can be a problem in applications where a consistent speed is required, such as in clocks and timers.