Electrical & Mechanical Fundamentals Flashcards

A motor nameplate reads 460V, 3-phase. What happens if this motor is connected to 230V, 3-phase?

Answer: Motor draws excessive current and overheats

Running a motor at half its rated voltage causes it to draw excessive current to maintain torque, leading to overheating and potential burnout.

Which type of bearing is best suited for applications with high radial loads and moderate axial loads?

Answer: Tapered roller bearing

Tapered roller bearings are designed to handle both high radial loads and significant axial (thrust) loads simultaneously.

What does the term 'power factor' describe in an AC electrical circuit?

Answer: The ratio of real power to apparent power

Power factor is the ratio of real (useful) power in watts to apparent power in volt-amperes, indicating how efficiently electrical power is being used.

In a V-belt drive system, what is the consequence of excessive belt tension?

Answer: Premature bearing failure and belt wear

Excessive belt tension places extreme radial loads on shaft bearings, accelerating bearing wear while also shortening belt life.

A single-phase 120V circuit has a resistance of 12 ohms. What is the current flow?

Answer: 10 A

Using Ohm's Law: I = V/R = 120/12 = 10 amperes.

What is the primary purpose of a pressure relief valve in a hydraulic system?

Answer: Limit maximum system pressure to prevent component damage

A pressure relief valve opens when system pressure exceeds a set limit, diverting fluid back to the reservoir to protect pumps, cylinders, and lines.

When measuring AC voltage with a multimeter, what type of value does the meter typically display?

Answer: RMS (root mean square) voltage

Standard AC voltmeters and multimeters display RMS voltage, which represents the equivalent DC heating value of the AC waveform.