A series motor is a type of electric motor where the armature winding is connected in series with the field winding. In this type of motor, the current flows through both the field and armature windings in series, which causes the magnetic field to be proportional to the current. This makes the series motor suitable for applications that require high starting torque.
Working of series motor:
When current is applied to the series motor, it flows through both the field and armature windings, producing a magnetic field that causes the armature to rotate. As the armature rotates, the current flowing through it changes, which changes the magnetic field and produces torque. The amount of torque produced is proportional to the square of the current flowing through the windings.
Construction of series motor:
- Armature: It is the rotating part of the motor that converts electrical energy into mechanical energy.
- Field windings: These are the stationary coils of wire that create a magnetic field when an electric current is passed through them.
- Commutator: It is a cylindrical structure that is mounted on the shaft of the motor and serves as a switch to reverse the current in the armature as it rotates.
- Brushes: These are stationary carbon or graphite blocks that press against the commutator and supply electrical power to the armature.
- Shaft: It is the rotating part of the motor that transmits mechanical power to the load
Types of series motor:
There are two types of series motors:
- Cumulative compound-wound motor – in this type of motor, the field winding is wound with a combination of series and shunt windings, which produces a magnetic field that is proportional to the current, but also has a constant component. This type of motor produces high starting torque and good speed regulation, but can be difficult to control.
- Differential compound-wound motor – in this type of motor, the field winding is wound with a combination of series and shunt windings that produce a magnetic field that is proportional to the current, but also has an opposing component. This type of motor produces lower starting torque than the cumulative compound-wound motor but has better speed regulation and control.
Advantages:
- High starting torque
- Suitable for applications with high load variations
- High power-to-weight ratio
- Simple and rugged construction
- Low cost compared to other types of motors
Disadvantages:
- Poor speed regulation
- Can be difficult to control
- Can easily draw excessive current and overheat if the load is too high
- Not suitable for applications requiring constant speed.
Applications
- Traction: Series motors are commonly used in electric trains, trams, and other electric vehicles that require high starting torque and variable speed control.
- Industrial machinery: Series motors are used in heavy-duty machinery such as large cranes, hoists, and conveyors.
- Tools: Series motors are commonly used in power tools such as drills, saws, and grinders.
- Appliances: Series motors are used in appliances such as vacuum cleaners, washing machines, and food processors.
- Elevators: Series motors are used in elevator systems because of their high starting torque and ability to handle heavy loads.
- Blowers and Fans: Series motors are commonly used in blowers and fans where high starting torque is required to overcome the resistance of the air.
- Hydraulic pumps: Series motors are used in hydraulic pumps because of their high starting torque and ability to handle high loads.