EGR 450 FINAL EXAM QUESTIONS
AND ANSWERS ALL CORRECT
What percentage of TCO (total cost of ownership) are the hardware costs in the PLC
system? - Answer- ~30%
What is the most important selection criteria in selecting the PLC? - Answer- Customer
preference
What does RTD stand for? - Answer- Resistance Temperature Detector
What are the steps for selecting a PLC? - Answer- 1. Understand the Process
2. Estimate the number of I/O
3. Hardware / Software Selection
4. Develop ladder logic
5. Determine Scan times
6. Determine memory usage
Enclosures protect from: - Answer- Temperature
Humidity
EMF/EMI
Shock & vibration
Dirt, oil, and other contaminants
When designing an electrical control system with high tech components that you are not
experienced with what should you do first? - Answer- read the manual
What is the surface area in square inches of an enclosure that measures 30" wide by
50" high by 10" deep? - Answer- 4600
According to OSHA standards a safety relay must be - Answer- Testable
Redundant
Self-checking
A safety system with single channel contacts and an ESTOP at most is rated Category
____ - Answer- 2
A safety system with dual channel contacts and a safety relay at most might be rated
Category ___ - Answer- 4
, The number of safety relays in your lab station is ___ - Answer- 2
What is the time in seconds within which both operators of a two hand start must be
actuated? - Answer- 0.5
If the flow of a pump is reduced from 100% to 60%, what percent is the power reduced
to? - Answer- 22
Name 5 fixed safety relays/modules. - Answer- Mat Control
Gate Monitor
ESTOP
Safe Speed Monitor
2 Hand Control
Order the sections of the VFD drive: - Answer- 1. Full wave diode bridge rectifier
2. choke & filter
3. inverter
Diodes in the rectifier sectioin conduct every _____ degrees. - Answer- 60
Which of the drive outputs are more sinusoidal? - Answer- current
What does PWM stand for? - Answer- Pulse Width Modulation
What does AOP stand for? - Answer- Add on Profile
Based on the standard U.S.A. frequency what is the base speed in RPM of a four pole
motor? - Answer- 1800
What does RMS stand for? - Answer- Root Mean Square/Squared
What does VFD stand for? - Answer- Variable Frequency Drive
What is the third harmonic based on the standard frequency in the U.S.A.? - Answer-
180
What does PLC stand for? - Answer- Programmable Logic Controller
The inventor of the electromechanical relay was - Answer- Joseph Henry
A motor starter contains an overload relay to protect the motor and it also contains a -
Answer- Contactor
Who won the "War of Currents"? - Answer- George Westinghouse
The invention of the PLC is commonly attributed to - Answer- Richard Morley
AND ANSWERS ALL CORRECT
What percentage of TCO (total cost of ownership) are the hardware costs in the PLC
system? - Answer- ~30%
What is the most important selection criteria in selecting the PLC? - Answer- Customer
preference
What does RTD stand for? - Answer- Resistance Temperature Detector
What are the steps for selecting a PLC? - Answer- 1. Understand the Process
2. Estimate the number of I/O
3. Hardware / Software Selection
4. Develop ladder logic
5. Determine Scan times
6. Determine memory usage
Enclosures protect from: - Answer- Temperature
Humidity
EMF/EMI
Shock & vibration
Dirt, oil, and other contaminants
When designing an electrical control system with high tech components that you are not
experienced with what should you do first? - Answer- read the manual
What is the surface area in square inches of an enclosure that measures 30" wide by
50" high by 10" deep? - Answer- 4600
According to OSHA standards a safety relay must be - Answer- Testable
Redundant
Self-checking
A safety system with single channel contacts and an ESTOP at most is rated Category
____ - Answer- 2
A safety system with dual channel contacts and a safety relay at most might be rated
Category ___ - Answer- 4
, The number of safety relays in your lab station is ___ - Answer- 2
What is the time in seconds within which both operators of a two hand start must be
actuated? - Answer- 0.5
If the flow of a pump is reduced from 100% to 60%, what percent is the power reduced
to? - Answer- 22
Name 5 fixed safety relays/modules. - Answer- Mat Control
Gate Monitor
ESTOP
Safe Speed Monitor
2 Hand Control
Order the sections of the VFD drive: - Answer- 1. Full wave diode bridge rectifier
2. choke & filter
3. inverter
Diodes in the rectifier sectioin conduct every _____ degrees. - Answer- 60
Which of the drive outputs are more sinusoidal? - Answer- current
What does PWM stand for? - Answer- Pulse Width Modulation
What does AOP stand for? - Answer- Add on Profile
Based on the standard U.S.A. frequency what is the base speed in RPM of a four pole
motor? - Answer- 1800
What does RMS stand for? - Answer- Root Mean Square/Squared
What does VFD stand for? - Answer- Variable Frequency Drive
What is the third harmonic based on the standard frequency in the U.S.A.? - Answer-
180
What does PLC stand for? - Answer- Programmable Logic Controller
The inventor of the electromechanical relay was - Answer- Joseph Henry
A motor starter contains an overload relay to protect the motor and it also contains a -
Answer- Contactor
Who won the "War of Currents"? - Answer- George Westinghouse
The invention of the PLC is commonly attributed to - Answer- Richard Morley
