Match two columns.

Make plan to the text and render it.

20.Make a short presentation on the topic: ”Noise measurement”.

Unit 14

ENERGY MEASUREMENT

Practice reading the following words.

In-depth, transfer, available, dynamic, observation, definite, circuit, hydraulic, simplicity, observation, methodologies, damped, torque, angular, consumed, negligible, frequencies, prototypes, sophisticated, defined.

Discuss in groups challenges and opportunities of energy measurement.

Read and translate text A

Find in the text English equivalents to the following words.

Фізична величина, електротехніка, процеси обміну енергії, електрична мережа, передача потужності, норматив часу, двополюсник, електричний ланцюг, інтервал спостереження, електрична тяга, електропривід, електростанція, динамічне вимірювання, електричний заряд, розподіл, споживання енергії, лічильник, магнітне поле, лінійний струм, ротор, додатковий резистор.

TEXT A

Energy is one of the most important physical quantities in any branch of science and engineering and especially in electrical engineering. Energy exchange processes lead to the study of electric networks from the physical point of view and allow an in-depth knowledge of power transfer within the electrical world and between electric and other forms of energy.

The definitions of energy and power represent the starting point for any successive study.

1. Energy is the amount of work that the system is capable of doing.

2. Power is the time rate of doing work.

Energy can be mathematically defined as the definite integral of the power over a given time interval .

The power available in a two-terminal section of an electric circuit is given by the product of the voltage across the terminals and the current flowing through the section itself (p=vi). The electric energy ( E ) flowing through the same section is defined by the integral of the power over the observation interval.

For this reason, energy measurement is a dynamic measurement, which means it varies with time. The energy measurement unit is the Joule (J); but for the electric energy, the Watt-hour (Wh) is most common.

The electrostatic energy is defined as the product of the electric charge and the difference of electric potential.

Electricity is generated from different forms of energy (thermal, hydraulic, nuclear, chemical, etc.) after electric transfer and distribution processes, it is converted to other forms of energy. The main feature of electric energy is the simplicity by which one can transfer it over long distances, control the distribution, and measure energy consumption.

Dc Energy Measurement

The simplest way to perform this measurement is to measure voltage and current and then compute the product: E=VI∆t where ∆ t is the observation interval measured by means of a chronometer or a time counter.

Note that dc systems are limited to a restricted number of applications in power systems, as, for example: electric traction, electric drives, electrochemical power plants, and for HVDC transmission system in limited operating conditions. All these cases, nevertheless, allow energy measurement either on the dc or ac side of the network.

The dc energy measurement has been performed in the past by means of different methodologies and instruments such as electrodynamics measurement devices (Electrodynamics dc Energy Meter) operating as an integrating wattmeter. This measuring instrument is built using a small dc motor without iron, whose magnetic field is generated by the line current flowing through a coil arranged as the fixed part of the system. The rotor is connected in series with an additional resistor and is powered by the line voltage ( V ).

Make word-combinations with the word “electric” and translate them into Ukrainian.