__________ drive is also called as Line shaft drive

Question

Examoogle · Accepted Answer

Group Drive

Explanation: Group drive, also known as line shaft drive, is a method in industrial electric drive systems where a single large electric motor is used to drive a long shaft (line shaft) to which several machines are connected via belts and pulleys. It was the standard approach in early industrial electrification before the advent of individual motor drives for each machine.

Working Principle: In this arrangement, a primary prime mover (typically a large motor) rotates a common line shaft suspended above the factory floor. Different machines are coupled to this shaft using a system of pulleys and leather belts. Clutch or belt-shifting mechanisms allow individual machines to be engaged or disengaged from the shaft while the motor continues to run.

Key Formulas: $P_{total} = \sum P_{machines} + P_{losses}$ — The total power rating of the motor must account for the sum of individual loads and significant mechanical transmission losses.

Key Points: Uses a common transmission element (line shaft) to distribute power.; Higher initial cost reduction but poor reliability due to single point of failure.; Significant mechanical energy losses occur due to friction in shafts and belts.; Limited speed control flexibility for individual machines.

Advantages: Lower initial capital investment compared to individual drives.; Efficient operation if all machines are running at full load continuously.

Disadvantages: Low overall efficiency due to mechanical transmission losses.; Single point of failure (if the motor fails, the entire factory section stops).; High maintenance requirement for belts and shafts.; Noise and safety hazards due to overhead rotating shafts and belts.

Applications: Old textile mills.; Small machine shops with clustered lathe or drilling stations.; Woodworking workshops.

Additional Info: Individual drive uses one motor per machine, providing superior control and higher efficiency.. Multimotor drive uses different motors for different parts of a single complex machine (e.g., in paper mills).

Answer: C is correct — Group drive is historically identified as the line shaft drive method where one large motor serves multiple machines.

Exam Tip: Always remember that in exams, 'Group Drive' is synonymous with legacy line shaft systems, while 'Individual Drive' is the modern standard for precision and modularity.

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