CPE Facility Operations & Maintenance 4 — Questions and Answers
Question 1: A plant engineer notices excessive bearing temperatures on a newly installed pump. After confirming correct lubrication, the NEXT most likely cause to investigate is:
- Incorrect impeller diameter
- Shaft misalignment between pump and motor (Correct answer)
- Insufficient pump discharge pressure
- Incorrect motor voltage
Correct answer: Shaft misalignment between pump and motor
Shaft misalignment creates excessive radial and axial loads on bearings, causing elevated temperatures even with proper lubrication.
Question 2: What is the recommended method for testing the integrity of a pressure vessel before returning it to service after repair?
- Visual inspection only
- Hydrostatic pressure test at 1.5 times MAWP (Correct answer)
- Operating at normal pressure for 24 hours
- Dye penetrant test on weld seams only
Correct answer: Hydrostatic pressure test at 1.5 times MAWP
Hydrostatic testing at 1.5 times the Maximum Allowable Working Pressure (MAWP) per ASME code verifies structural integrity after repair.
Question 3: In a facility energy audit, which calculation determines a motor's actual operating efficiency compared to its nameplate rating?
- Power factor × nameplate HP
- Measured shaft output power ÷ measured electrical input power (Correct answer)
- Rated HP × 0.746 kW/HP
- Line voltage × line current × power factor
Correct answer: Measured shaft output power ÷ measured electrical input power
Operating efficiency equals actual shaft output power divided by electrical input power, revealing if the motor is degraded from its nameplate rating.
Question 4: What is the purpose of an interlock system on a large industrial fan or blower?
- To adjust fan speed based on demand
- To prevent the fan from operating under unsafe conditions (Correct answer)
- To measure air flow rate continuously
- To balance the impeller automatically
Correct answer: To prevent the fan from operating under unsafe conditions
Interlocks automatically shut down or prevent startup of equipment when monitored parameters exceed safe operating limits.
Question 5: A facility's electrical demand charges are increasing. Which strategy MOST directly reduces peak demand billing?
- Switching to LED lighting
- Load shedding or staggering large motor starts during peak periods (Correct answer)
- Power factor correction capacitor banks
- Installing sub-metering on all circuits
Correct answer: Load shedding or staggering large motor starts during peak periods
Staggering large motor starts or shedding non-critical loads during peak periods directly reduces the highest 15- or 30-minute demand interval used for billing.
Question 6: Which type of valve is MOST appropriate for throttling flow control in a process line?
- Gate valve
- Globe valve (Correct answer)
- Ball valve
- Check valve
Correct answer: Globe valve
Globe valves are designed for throttling because their disc moves perpendicular to flow, allowing precise intermediate positions.
Question 7: In a facility's fire protection system, a dry-pipe sprinkler system is preferred over a wet-pipe system when:
- Higher flow rates are needed
- Faster activation response is required
- Piping is located in unheated areas subject to freezing (Correct answer)
- The facility has high-rack storage
Correct answer: Piping is located in unheated areas subject to freezing
Dry-pipe systems fill with pressurized air rather than water, preventing freezing in cold environments such as unheated warehouses.
CPE Facility Operations & Maintenance 4
A plant engineer notices excessive bearing temperatures on a newly installed pump.
After confirming correct lubrication, the NEXT most likely cause to investigate is: