Solved Example: 9050-01

The throughput rate of a production system is 30 units per hour. The average flow time is 20 minutes and the cycle time is 3 minutes. The average inventory (in units) in system is: (GATE PI 2016)

A. 1.5

B. 9

C. 10

D. 11.33

\begin{align*} \mathrm{Throughput\ Rate} &= \dfrac{\mathrm{Work\ In\ Process\ Inventory}}{\mathrm{Throughput\ Time}}\\ \dfrac{30}{60} &= \dfrac{\mathrm{WIP}}{20}\\ \mathrm{WIP} &= 10\ \mathrm{Units} \end{align*}

Correct Answer: C

Automation is delegation of human control function to technical equipment for:

• Increasing productivity
• Increasing quality
• Reducing cost
• Increasing safety in working conditions

• HMI: Human Machine Interface
• SCADA: Supervisory Control and Data Acquisition
SCADA is real time industrial process control system used to centrally monitor and control remote or local industrial equipment such as motor, valve, pump, relay, etc.
• PLC: Programmable Logic Controller
A PLC is a solid state device which performs sequential operation in industrial environment and replace timer, counter, relay, etc.

Solved Example: 9174-01

PLC has become popular, because it performs _________ functions. (UPPCL JE Nov 2019 Shift II)

A. Data transfer

B. Timing and counting

C. Logical

D. Analog

Correct Answer: B

Solved Example: 9174-02

PLC operates on the following signals: (UPPSC AE Mech Dec 2020)

A. Digital

B. Impulse

C. Analog

D. Frequency

Correct Answer: A

Solved Example: 9174-03

Which of the following device system is capable of operating in high temperature with poor conditions in dusty, dirty, corrosive atmospheres and withstand shock and vibration? (UPPCL JE Nov 2019 Shift I)

A. Laptop

B. iPad

C. Personal computer

D. PLC

Correct Answer: D

Solved Example: 9174-04

A technology for the application of mechanical, electronics, and computer-based systems to control and operate the systems is called: (UPPSC AE Mech Dec 2020)

A. PLC

B. Sequential controller

C. Microprocessor-based systems

D. Automation

Correct Answer: D

Solved Example: 9174-05

In a PLC, which of the following is NOT a subpart of Central Processing Unit (CPU)? (UPPCL JE Elec Nov Shift II)

A. Programmer

B. Microprocessor

C. Memory

D. Power supply

Correct Answer: A

Solved Example: 9174-06

Programmable Logical Controllers are the devices that were invented basically to replace: (UKPSC JE Electrical Nov 2015)

A. Switches

B. Circuit Breakers

C. Relays

D. None of the above

Correct Answer: C

• Line Balancing is used to minimize the imbalance between machines or personnel while meeting required output.
• Objectives of this method are:
  1. Determine cycle time
  2. Calculate theoretical minimum number of workstations.
  3. balance the line by assigning specific tasks to workstations.
• The sum of operational times of workstations should not exceed cycle time.

Solved Example: 9049-01

An electronic equipment manufacturer has decided to add a component sub-assembly operation that can produce 80 units during a regular 8-hour shift. This operation consists of three activities as below.
M = Mechanical Assembly = 12 min
E = Electrical Wiring = 16 min
T = Test = 3 min
For line balancing the number of work stations required for the activities M, E and T would respectively be : (GATE ME 2004)

A. 2, 3, 1

B. 3, 2, 1

C. 2, 4, 2

D. 2, 1, 3

Correct Answer: A

Solved Example: 9049-02

In an assembly line for assembling toys, five workers are assigned tasks which take times of 10, 8, 6, 9 and 10 minutes respectively. The balance delay for the line is: (GATE ME 1996)

A. 43.3%

B. 14.8%

C. 14.0%

D. 16.3%

Correct Answer: C

Solved Example: 9049-03

Line balancing is related to: (BPSC AE Paper VI Mech 2012)

A. Product layout

B. Process layout

C. Hybrid layout

D. Cellular layout

Correct Answer: A

Solved Example: 9049-04

A production line is said to be balanced when: (UPPSC AE Mech Paper I May 2022)

A. There are equal number of machines at each work station

B. The operation time at each work station is same

C. There are equal number of operators at each work station

D. The waiting time for service at each station is same

Correct Answer: B