Specialist Technician Interview Questions and Answers

PLC (Programmable Logic Controller) is a digital computer used for automation of electromechanical processes.

• PLC receives input signals from sensors and switches

• It processes the input signals based on the programmed logic

• It controls the output devices such as motors, valves, and lights

• PLC programming is done using ladder logic or other programming languages

Tests performed on motors include insulation resistance test, winding resistance test, vibration analysis, and current signature analysis.

• Insulation resistance test checks for any breakdown in insulation

• Winding resistance test measures the resistance of the motor windings

• Vibration analysis detects any mechanical issues in the motor

• Current signature analysis monitors the current waveform for abnormalities

Transformers work by transferring electrical energy between two or more circuits through electromagnetic induction.

• Transformers consist of two coils of wire, known as the primary and secondary coils.

• When an alternating current flows through the primary coil, it creates a changing magnetic field.

• This changing magnetic field induces a voltage in the secondary coil, transferring electrical energy.

• The ratio of the number of turns in the primary and secondary coils determines the ...read more

Power factor is a measure of how effectively electrical power is being used in a circuit.

• Power factor is the ratio of real power (kW) to apparent power (kVA) in a circuit.

• It is a number between 0 and 1, with 1 indicating perfect efficiency.

• Low power factor can result in increased energy costs and inefficient use of electrical equipment.

• Power factor correction techniques, such as adding capacitors, can improve power factor.

• Example: A circuit with a power factor of 0.8 means th...read more