03-05 Advanced AC Topics

RMS

Root mean square = √ (the average of the squares)

Phase

One AC cycle is represented by an angle that sweeps from 0° to 360° (or 0 radians to 2π radians)

Single phase or Three phase

Electricity is generated in 3 phases for max efficiency.
But distributed to households as individual phases.
Each phase max 12 kVA.
Rule of thumb: if power consumption >10kW, upgrade to 3-phase.

Even in a 3-phase home, appliances are still single-phase 230V.
Typically true 3-phase equipment (e.g. induction motors) is only found in industrial installations.

Power Factor

Difference in phase between voltage and current.
Not usually a topic that concerns residential users. Residential PF ≈ 1. Not penalised by TNB.
Industrial users with significant inductive loads (e.g. motors) need to apply capacitive power factor correction measures.

Earthing Systems

TT - most common in Malaysia
TN-C
TN-C-S
TN-S
IT

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