According to API 541, the combined runout for areas on the shaft that are to be observed by radial vibration probes shall not exceed:
Correct Answer: D
The correct answer isD. In API 541, when a motor shaft is monitored usingradial vibration probes, the probe- observed shaft surface must meet a strictcombined runoutlimit so that the vibration reading reflects actual machine vibration rather than shaft surface irregularity, eccentricity, or electrical and mechanical runout effects. API 541 sets this limit at25% of the allowed unfiltered peak-to-peak vibration amplitude or 6.4 µm 0.25 mils, whichever is greater. This requirement is important because excessive runout can distort probe signals and produce misleading vibration data during shop testing and acceptance. From a source inspection standpoint, this is a critical verification item during motor testing for large rotating equipment. If the shaft finish and probe track are not within the required runout limit, the vibration measurements cannot be relied on for acceptance decisions. The API guide includeselectric motors over 500 HPas a covered equipment category and emphasizes inspection and surveillance activities tied to applicable standards, testing, and verification of compliance during manufacture. Therefore,option Dis the correct API 541 requirement.
Question 27
Which source inspection effort level is MOST appropriate for the highest-risk equipment?
Correct Answer: D
Question 28
What requirement shall be included in a lockout/tagout procedure?
Correct Answer: D
Question 29
A source inspector reviewing a control panel should verify wiring against which project document as a core inspection activity?
Correct Answer: A
Question 30
According to NEMA ICS 2, a provision for pad locking shall be provided:
Correct Answer: B
The correct answer isB. UnderNEMA ICS 2for motor controllers and combination starters, the required provision forpadlockingis associated with theexternal operating handle. This arrangement allows the disconnecting means or operating mechanism to be secured in the desired position, typically for safety isolation and lockout purposes during maintenance or inspection. It is a functional safety feature tied directly to operation of the controller, not merely to enclosure access. The other options are not the standard requirement in this context. Padlocking thedoor,wireway, orrear doormay be used in some installations for security or restricted access, but those are not the specific NEMA ICS 2 provisions identified for the controller operating mechanism itself. The standard intent is to ensure that the operating handle can be locked so the equipment cannot be unintentionally operated while personnel are working on or near it. From an API source inspection perspective, this falls under verification ofMCC construction details, safety features, interlocks, and compliance with applicable referenced standardsduring shop inspection and quality surveillance. Therefore, the correct answer ison the external operating handle, which makesoption Bthe verified answer.
