What is a Group Electric Drive? (Types of Electric Drive)

The combination of an electric motor, energy transmitting shaft and control devices for motion control is known as electric drive. The following figure shows the block diagram of a typical electric drive.

Based on their assembly, electric drives are classified into the following categories −

• Individual Drive

• Group Drive

• Multi-motor drive

Group drive

When several machines are organized on a single shaft and are driven by a single large motor, this system is known as group drive. Group drive is also known as line shaft drive because a large sized motor (called main motor) drives a common shaft. To the common shaft, a number of small machines are connected by means of multi-stepped pulleys.

The following figure shows the block diagram of group drive.

Advantages of Group Drive

The advantages of group drives include the following −

• As group drive uses a large sized single motor, so there is considerable saving in cost.

• Group drive has low maintenance cost.

• In case of group drive, the overload occurring for main motor is very less.

• When the main motor operates near rated capacity, then the power factor and efficiency of the group drive be better.

Disadvantages of Group Drive

The disadvantages of group drives include the following −

• If there is a fault in main motor, then it causes stopping of all the small machines.

• In group drive, the small machines have to be installed at places which is convenient for shafting.

• .In group drive, the speed control of individual small machine is not possible

• In case of group drive, high amount of power is wasted in power transmission (in pulleys, etc.).

• In group drive, future expansion is not possible.

• When only a few number of machines are required to be operated, then the main motor operates with a very less capacity. Thus, its power factor and efficiency be poor.

• The layout of group drive is fixed and cannot be change. Also, appearance of layout is not good.

• Noise produced by group drives is high.

Applications of Group Drive

The main applications of group drives are listed below −

• Grain processing industries

• Food grinding mills

• Paper mills

• Textile mills

• Workshops, etc.