Magnetism, Electricity, and Induction

Magnetism

• A force attracting ferromagnetic metals like iron, nickel, and cobalt.
• Also a force repelling diamagnetic materials like antimony and bismuth.

Magnet

• Displays the properties of magnetism

Magnetic Field

• Radiates from the two poles of a single magnet
• Can also exist between the poles of two magnets

Induction

• Occurs when a conductor is moved through a magnetic field
• Also occurs when a magnetic field is moved across a fixed conductor
• Voltage is produced in the conductor, causing current to flow
• Current flow is thus induced in the conductor.

Direct Current (DC)

• Current flows in one direction in an electrical circuit.

Alternating Current (AC)

• Continuous reversal of current flow direction, such that current flows in one direction at one point and the opposite direction at another.

Single-Phase Power

• Electrical power source with a single AC waveform
• Used for residences and small businesses
• Efficient for low-power appliances, heating, and lighting.
• Power transferred through two wires: a live (hot) wire and a neutral wire

Three-Phase Power

• Uses three ACs, each phase offset by 120 degrees
• Used in heavy industry due to its effectiveness, steadiness, and efficiency

Transformer

• Electrical device transferring AC and voltage from one circuit to another using induction
• The ratio of output voltage to input voltage is approx. equal to secondary coil turns to primary coil turns

Types of Electrical Load

Resistive Load

• Converts electrical energy into heat
• Current and voltage sine waves are in phase

Capacitive Load

• Current peaks before its voltage
• Current and voltage waves are out of phase, with current leading by 90 degrees

Power in AC Circuit

• True power (watts or kilowatts) is the 'working power', creating heat, light, or motion
• Reactive power (VAR or kVAR) generates magnetic field for inductive devices
• Apparent power (VA or kVA) is the 'power available to use'
• Power factor describes the phase voltage between difference and current and affects actual power dissipated

Power Factor (PF)

• Measures how effectively total power is being used (ratio of true power to apparent power)
• When PF is less than 1.0, circuit wiring carries more current than needed
• PF ranges from 0 to 1, often expressed as a percentage
• Power companies measure apparent power in volt-amperes (VA) but bill for real power in watts (W) consumed

Effects of Inductive Loads in a Circuit

• Low power factor, can cause higher current draw, and voltage fluctuations

Effects of Inductive Loads in a Circuit

• Higher system losses, an impact on the power of motors

Mitigating Inductive Load Effects

• Choosing motors with high power factor designs or distributing load, adding capacitors in parellel
• PF correction reduces load currents and electrical load, saving hardware, and can avoid penalties by power companies

Impedance (Z)

• Measures resistance to AC current flow, considering resistance, inductance, and capacitance

The Electrical Code

• Specifies maximum provisions for protecting people and property from improper use of electricity and equipment

National Electrical Code (NEC)

• Set of specifications and standards in the form of a model code that the US adopts

The Philippine Electrical Code (PEC)

• Comprehensive standards and guidelines for electrical systems in the Philippines
• PEC I is for electrical installation inside buildings and PEC II outside

The Philippine Electrical Code

• Aims to set safety standards, consistency and uniformity, compliance, code enforcement, and the promotion of efficient electrical systems
• Protects Investments and adapts to technologies

The Philippine Electrical Code Users

• Electrical Engineers and Designers, Electricians and Electrical Contractors
• Inspectors and Code Enforcers, Architects and Building Design Professionals
• Facility Managers and Maintenance Personnel
• Educational Institutions, Gov. Agencies and Authorities
• Manufacturers and Suppliers, Consumers and Property Owners

Republic Act 7920

• New Electrical Engineering Law, comprehensively regulating the practice, licensing, and registration of electrical engineers

Electricians Institute of Integrated Electrical Engineers of the Philippines, Inc. (IIEE)

• Organization of electrical practitioners and accredited by PRC

Electrical Permits

• Electrical Permit is required for any installation work under Republic Act 7920

Electrical System and Materials

• Electrical power transmission involves bulk movement of electrical energy

Republic Act No. 9136

• Electric Power Industry Reform Act (EPIRA)
• Sought to restructure the power industry by privatizing

National Transmission Corporation (TRANSCO)

• Created to assume the electrical transmission function

National Grid Corporation of the Philippines (NGCP)

• Ensures transmission assets are in optimal condition

Types of Electric Power Distribution Systems

• Distribution system delivers electric energy to the end user. Can be classified:
• according to the nature of the supply i.e. AC or DC
• by type of connection ie. radial, ring or interconneced
• by type of construction (overhead or underground)

AC Distribution System

Primary Distribution System

• Operates at higher voltages
• Handles larger blocks of electrical energy
• Carried out by 3-phase, 3-wire systems

Secondary Distribution System

• includes the range of voltages consumer uses

Types of Distribution System According to Type of Construction

• According to the type of construction, the distribution system can be underground

Underground distribution system

• Conductors are placed under the surface of streets or sidewalks

Overhead distribution system

• Conductors are mounted on poles

Duct system

• Cables pulled through tubes (may or may not be encased in concrete)
• Direct burial system where cables are buried directly in the earth
• The service entrance includes the connection of the utility to the service disconnect, excluding the metering

Electric meter

• Used by the utility company to measure and record electrical energy

Smart Meter

• Provides two-way communication
• Helps maintain more reliable electric service