---
title: "Group drive vs multimotor drive"
subject: "Utilization of Electrical Energy"
chapter: 2
key: "semester_7/utilization_of_electrical_energy:group-vs-multimotor-drive"
source: https://www.bctengineer.com/q/semester_7/utilization_of_electrical_energy/group-vs-multimotor-drive
site: BCT Engineering
---

# Group drive vs multimotor drive

Utilization of Electrical Energy · Chapter 2: Electric Drive System

- Asked in: 2080 Bhadra, 4 marks
- Video: [Classification of electric drives/Group drive/Individual drive/Multi-motor drive](https://www.youtube.com/watch?v=Sp6_SbnXuFA) — Read Electric Vehicle
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/utilization_of_electrical_energy/group-vs-multimotor-drive
- Whole chapter: https://www.bctengineer.com/md/semester_7/utilization_of_electrical_energy/chapter-2

## Question

Differentiate between group drive and multimotor drive. Discuss the merits and demerits.

## Short answer

Group drive has one motor driving many machines through shafts and belts, giving low initial cost but low efficiency, no individual control, and motor failure stops all. Multi-motor drive uses several motors on one machine, each driving a section, giving better efficiency, precise coordination and safety but higher cost and complex control.

## Answer

In a **group drive**, one motor drives several machines through a line shaft, belts and pulleys. In a **multi-motor drive**, one machine has several motors, each driving a separate part of it (e.g. a crane with hoist, trolley and travel motors).

| Point | Group drive | Multi-motor drive |
|---|---|---|
| Motor-machine relation | One motor, many machines | Many motors, one machine |
| Transmission | Line shaft, belts, pulleys | Each motor coupled directly to its part |
| Control | No individual control | Each section controlled separately, coordinated |
| Efficiency | Low (shaft and belt losses) | High |
| Example | Old workshop line shaft | Cranes, rolling mills, paper machines |

**Group drive**
- Merits: low initial cost (one large motor); motor can be rated for the diversity of loads, so total rating is less.
- Demerits: low efficiency; failure of the motor stops all machines; no individual speed control; belts and pulleys are unsafe, noisy and untidy; machine layout fixed along the shaft.

**Multi-motor drive**
- Merits: each operation gets the most suitable motor and speed; precise, automatic coordination of sections; high efficiency; compact, safe and flexible.
- Demerits: high initial cost; complex control and coordination system; needs skilled maintenance.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is the difference between group drive and multi-motor drive?
   A. Group: one motor, many machines; multi-motor: many motors, one machine
   B. Group: many motors, one machine; multi-motor: one motor, many machines
   C. Both use one motor
   D. Both use line shafts
   Answer: A. A group drive has one motor for several machines; a multi-motor drive has separate motors for parts of one machine. (Key point: Motor-machine relation)

2. What is a merit of group drive?
   A. Precise coordination
   B. Low initial cost as one motor serves all
   C. High efficiency
   D. Individual speed control
   Answer: B. One large motor is cheaper initially and can be rated for the diversity of loads. (Key point: Group drive merit)

3. What is a demerit of multi-motor drive?
   A. Low efficiency
   B. Complex control and high initial cost
   C. Unsafe belts
   D. Fixed layout
   Answer: B. It needs several motors and a complex coordination system with skilled maintenance. (Key point: Multi-motor demerit)

## Related in Utilization of Electrical Energy

- [Group vs individual drive; constant torque vs power](https://www.bctengineer.com/question.md?key=semester_7%2Futilization_of_electrical_energy%3Agroup-individual-constant-torque-power-drive) — Utilization of Electrical Energy, chapter 2
- [Group drive vs individual drive](https://www.bctengineer.com/question.md?key=semester_7%2Futilization_of_electrical_energy%3Agroup-vs-individual-drive) — Utilization of Electrical Energy, chapter 2
- [Types of electric drives with merits and demerits](https://www.bctengineer.com/question.md?key=semester_7%2Futilization_of_electrical_energy%3Aelectric-drive-types-merits) — Utilization of Electrical Energy, chapter 2
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- [Block diagram of electric drive; series vs shunt starting](https://www.bctengineer.com/question.md?key=semester_7%2Futilization_of_electrical_energy%3Adrive-block-diagram-motor-starting) — Utilization of Electrical Energy, chapter 2

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