Questions focus on equipment upkeep, fault diagnosis, preventive and corrective maintenance routines, and practical hands-on skills in industrial settings.
Preventive: scheduled (oil change every 500 hrs). Predictive: condition-based (vibration analysis showing bearing wear). Corrective: repair after failure. Predictive maintenance is the most sophisticated, so highlight it if you've done it.
Key steps: de-energize and LOTO, remove the motor, use a proper bearing puller, clean the shaft, heat the new bearing (induction heater), install with the correct tool and never hammer directly. Contamination and incorrect force are the biggest causes of premature failure.
Mention grease (NLGI grade), oil (viscosity ISO grade), and automatic lubrication systems. Always refer to the OEM manual for type and quantity. Show awareness of over-lubrication risks: it's as harmful as under-lubrication.
Check for winding resistance (unequal phases means imbalance), insulation resistance to ground (megohmmeter, below 1MΩ is a concern), and continuity. Show you know the difference between measuring resistance and testing insulation.
Causes: misalignment, overloading, improper tension, material buildup on pulleys, worn scrapers. Show you inspect tracking, tension, and splice condition during PMs, not just when something breaks.
Steps: observe and describe the symptom (frequency, location), check mounting bolts, inspect couplings, measure vibration if tools are available, check bearings and alignment, inspect belts and chains. Systematic thinking matters more than guessing.
Leaks: use soap solution or an ultrasonic detector. Slow cylinder: check regulator pressure, flow control valves, cylinder seal condition, and air supply size. Mention that you always depressurize the system before any maintenance.
Prioritize by safety risk first, then production impact (bottleneck machines), then repair time (quick fix vs long repair). Communicate the priority decision to your supervisor immediately rather than going silent and starting work.
Operators see problems first. Ask: "When did it start? Was there any unusual sound, smell, or product defect before it failed? What were you running?" Show respect for their knowledge: the best technicians treat operators as partners.
Start with the OEM manual, check maintenance history in the system, talk to someone who knows the machine, and do a visual inspection before touching anything. Show you don't improvise blindly: a methodical approach prevents additional damage.
Choose a story with real technical detail. Highlight what made it complex, what resources you used, who you consulted, and what you learned. This is your chance to show depth, so avoid a vague answer.
Mention technical training courses, manufacturer seminars, video tutorials for specific equipment, trade publications, asking more experienced colleagues. Show genuine curiosity: lifelong learning is highly valued in U.S. companies.
