Types of electrical drive

Types of drive:

1) Group drive

2) Individual drive

3) Multi rotor drive

1) Group drive:

In this drive, one higher capacity Motor is used to drive various machines. This motor runs over head line shaft by means of belt as shown in below figure.

Number of pulleys are mounted on line shaft and each of this pulley drive its own machine by means of belts. Each particular machine has two pulleys; loose pulley and fast pulley.

Machine will start running when belt is changed over from loose pulley to fast pulley and machine will stop running when belt is changed over from fast pulley to loose pulley. This change over can be done with the help of lever.

Advantages:

1) minimum overall maintenance

2) very useful where sequence continuity is required

3) at full load, this scheme is most economical scheme compared to other schemes.

4) cost of drive is less compared to individual drive

Disadvantages:

1) if some trouble arises in main motor, entire system will be stop working.

2) power loss on shafting and transmission system

3) minimum flexibility for placement of different machines

4) appearance is not good

5) main motor almost working on underload condition resulting in reduction of efficiency and power factor.

2) individual drive:

In this type of drive separate motors for each machine drive is used closed it. The driving motor is choose according to the individual load.

Advantages:

1) when breakdown occur, only one machine will affected.

2) maintenance cost is minimum

3) working at higher power factor and efficiency

4) it is more reliable and it is easy to shift at one place to other place

Disadvantages:

1) this drive system is costly as individual motor and individual control gears is required

2) power loss occur in energy transmission

3) multi motor drive:

It consists of numbers of individual drives, each drive is used for different purposes and function.

This types of drive have their different applications in paper making machine, cable manufacturer units, metal cutting machine, rolling mills and similar other type of machinery.

Factors affecting selection of drive:

1) types of electrical supply: AC / DC

2) nature of drive: individual or group drive

3) nature of load: whether load demands less or high starting current

4) electrical characteristic of motor: starting, running, speed control, braking

5) rating and size of motor: continuous or variable load cycle. Whether the overload capacity or pull out torque meet the requirements.

6) mechanical characteristics: nature of bearing, type of enclosure, transmission of drive, noise

7) economic consideration: running cost and capital cost.