Switches Flashcards
What is the first thing you should do prior to working on a switch?
Communicate with operations.
Why is it important to communicate with operations before working on a switch?
- To learn the criticality of the switch.
- To understand the nature of the rpoblem.
- To discuss potential impacts.
Where would you find safety critical procedures?
Maximo and safety critical list. ***Research
What is the difference between calibrating a rising vs. a falling switch?
For rising, start below the switch and monitor the switch as you rise past the set point.
For falling start above the the setpoint and monitor as you fall below the set point.
When would you use normally open versus normally closed contacts?
Normally open-for decreasing set points.
Normally closed-for increasing setpoints.
When calibrating a differential switch which port connect to the pressure source?
The high side to pressure source.
Low side to atmosphere.
What kind of switch would you us a UV Test Lamp on?
Fire eye flame detection.
What color on a thermocouple is alway negative?
The red wire is always negative.
What is the LEL alarm setpoint and and LEL shutdown setpoint?
10% alarm.
50% Shut down
(According to the Skill Assessment Guide)
How do you take a gas detection system out of service for calibration?
Follow the safety systems procedure. System bypass switch etc.
How do you take a fire detection system out of service for function testing?
Follow the safety systems procedure. System bypass switch etc.
What are the steps to access and modify set points on temperature monitoring systems?
Consult vendor manuals. Ex Murphy TTD. MOC?
What are common failures of a level switch?
Mechanical jam, displacer damage, switch failure, blown fuse, faulty wiring, PLC failure.
What coul cause a malfunction in a pressure switch?
Plugged sensing line, Bad wiring, blown fuse, contact failure.
Where would you find information for replacement parts for a damaged pressure or level switch?
Vendor manual, warehouse inventory.
