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 electromagnets. It is a very versatile motor that can be used for a variety of applications, including signaling devices and many kinds of timers.
D.C. shunt motors are typically used in applications where a constant speed is required, such as in conveyor belts and elevators. They are also used in applications where a high starting torque is required, such as in cranes and hoists.
D.C. shunt motors are typically more expensive than other types of motors, but they offer a number of advantages, including:
- High efficiency
- Low maintenance
- Long life
- Constant speed
- High starting torque
D.C. shunt motors are available in a variety of sizes and power ratings. They can be either single-phase or three-phase motors.
Single-phase D.C. shunt motors are the most common type of D.C. shunt motor. They are used in a variety of applications, including signaling devices, timers, and small appliances.
Three-phase D.C. shunt motors are more powerful than single-phase D.C. shunt motors. They are used in a variety of applications, including conveyor belts, elevators, and cranes.
D.C. shunt motors are a versatile and reliable type of electric motor. They are used in a variety of applications, including signaling devices, timers, and many kinds of machinery.
The other options are not as suitable for signaling devices and many kinds of timers.
A D.C. series motor is a type of electric motor that uses direct current (DC) to power its electromagnets. It is a very powerful motor, but it is not as versatile as a D.C. shunt motor. D.C. series motors are typically used in applications where a high starting torque is required, such as in cranes and hoists.
An induction motor is a type of electric motor that uses alternating current (AC) to power its electromagnets. It is a very efficient motor, but it is not as versatile as a D.C. shunt motor. Induction motors are typically used in applications where a constant speed is required, such as in conveyor belts and elevators.
A reluctance motor is a type of electric motor that uses the principle of reluctance to produce torque. It is a very simple motor, but it is not as versatile as a D.C. shunt motor. Reluctance motors are typically used in applications where a low starting torque is required, such as in fans and pumps.