Introduction

 Introduction   AU : Dec.-05, 06, May-05,17   

• It is known that electrical energy is rarely available naturally and it is required to produce it. The generator is a well known device which converts mechanical energy into an electrical energy. Thus there involves a process of energy conversion. Similarly in many devices it is necessary to convert electrical energy into some other form of energy such as mechanical, sound, light etc.

Key Point : Thus the electromechanical energy conversion process involves the transfer of energy between electrical and mechanical systems, via the electric field or magnetic field.

• The process of electromechanical energy conversion is basically reversible in nature, apart from the losses taking place in the device. The energy cannot be created or destroyed but it can be transformed from one form to other. Hence practically electromechanical energy conversion devices are very important.              

• In practice, three types of electromechanical energy conversion devices are in use.

1. The various transducers such as microphones, loudspeakers, strain gauge, thermocouples etc. These devices handle low energy signals. These devices mostly operate on vibrating motion.

2. The devices which produce the mechanical force or torque based on translatory motion such as electromagnets, relays, solenoids, actuators etc. These devices handle large energy signals than the transducers.

 3. The devices used for continuous energy conversion using rotational motion such as generators, motors etc. These devices handle very large energy signals.

Key Point : Though energy conversion can take place via electric or magnetic field, the magnetic field is practically used as is most suited for practical devices and the energy storing capacity of magnetic field is much higher than that of electrical field.

• The fields involved in devices must be slow such electromechanical varying due to inertia associated with the mechanical parts. Such fields are called quasistatic fields.

• The Fig. 2.1.1 (a) shows the representation of an electromechanical energy conversion device which converts mechanical energy to electrical. It is a generator. While the Fig. 2.1.1 (b) shows the representation of an electromagnetical energy conversion device which converts electrical energy into mechanical. It is a motor.

• This chapter explains the principles electromechanical energy conversion.

Review Question

1. Explain the concept of electromechanical energy conversion with neat diagram. AU : Dec.-05, 06, May-05, Marks 8, May-17, Marks 13