SLC22/WK3:Electrical Basics: Understanding Generators, Motors, Transformers, and Lightning Arresters

A. Differences in Generators Motors and Transformers.

1. How do they work?

• Generator: transforms Mechanical energy into Electrical energy.

• Motor: transfroms Electrical energy into Mechanical energy.

• Transformer: Transfers electrical energy between two or more circuits based on electromagnetic induction without changing its form.

1. Input and Output

• Generator: Mechanical energy is provided as the input, then Electrical energy is supplied as the output.

• Motor: Electrical energy is provided as the input, then Mechanical energy is provided as the output.

• Transformer: Both input and output involve electrical energy, with a difference in their voltage and current.

1. What do they look like?

• Generator: Rotor, Stator, and slip rings are among its components.

• Motor: Armature, rotor, and brushes are among its components.

• Transformer: It has a primary and secondary winding together with a core.

B. Lightning Protection Equipment used in Electricity Industry

Systems damage by lightning can be prevented by the use of air terminals whose other name is lightning arrestors. There are several types as listed below:

1. Rod Gap Lightning Arresters: It light spark and can cut high voltage as well.

2. Metal Oxide Varistor (MOV) Arresters: This is one of the most effective and reliable types which requires less maintenance.

3. Expulsion-Type Arresters: It is used in low voltage areas and is also efficient in cost.

Such lightning arrestors are placed at various locations such as substations, power stations and even at transmission lines with required checkups to ensure proper working conditions.

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C. Steps in Calculation of Current for Generator

1. Actual Current of a Three Phase Generator of 1500 KVA which has a Power factor of 0.9

Formula:

[ I = \frac{KVA}{\sqrt{3} \times V \times PF} ]

Consider V equal to 400 volts

[ I = \frac{1500 \times 1000}{\sqrt{3} \times 400 \times 0.9} ]

[ I = 2408.55 \text{A} ]

1. Load Current When Output is 80 percent of the Capacity

Formula:

[ I_{\text{load}} = I \times 0.8 ]

[ I_{\text{load}} = 2408.55 \times 0.8 = 1926.84 \text{A} ]

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D. Required KVA Generator for Electricity Supply to our House Hold Devices.

Appliances:

• Lights: 5 x 30W = 150W

• Fans: 3 x 70W = 210W

• Refrigerator: 1.5 kW

• Air Conditioner: 2.0 kW

Total Power:

[ 150 + 210 + 1500 + 2000 = 3860W ]

To convert them into KVA:

[ KVA = \frac{W}{1000 * PF} ]

Considering power factor = 0.9:

[ KVA = \frac{3860}{1000\times 0.9} \approx 4.29\text{KVA} ]

To cover a safety margin, at least 5 KVA rated generator should be purchased.

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E. Practical: How to Build a Lightning Rod

Materials:

• Copper rod ~ 1 meter long

• Thick copper wire

• A grounding rod

• Drill, screws and possibly concrete

Steps:

1. Fix Copper Pole: Make it a point to ensure that it is properly secured on the top of the house for example on a rooftop using screws.

2. Attach Thick Copper Wire: Use clamps to connect one end of the wire onto the rod.

3. Attach & Ground the Wire: A grounding rod must be placed at a depth of at least 8 feet into the ground. The wire is then to be clamped onto the grounding rod.

4. Verify Connections: This wire should be clamped for a secure connection and to ensure that weather does not affect them.

5. Verify Setup: Using a multimeter, check for continuity between the rod and ground.

6. Securitas Firmitas Area – Adorn the area around grounding rod with concrete for structural integrity (optional).

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Nota: An earthing system placed at high positions and made from copper serves as a effektivitestas metriculator.