The electrical drive was introduced in Russia by B.S. Iakobi in 1838. He designed a DC electric motor supplied from a DC battery and used to propel a boat. This is a simple application and started the use of DC motor as a drive. Although, it takes time to use in industries. Today, the drive is a common equipment in all industries and many other applications.
What is an Electric Drive?
The motion of an electrical machine controlled by some systems, this type of system called an electrical drive. A Drive is a combination of various systems combined together for the purpose of motion control. An electric motor used to control the system and that’s why this drive known as an electrical drive.
The speed of a motor can controlled by controlling the input voltage and current of the motor. But, for precise control of motion, the drive used. Nowadays, the software used to control the motion of the shaft. Therefore, the concept of a drive to make more and more accurate and precise control of motion.
The drive widely used in industries as well as in domestic applications. Drives used in industries instead of prime movers for diesel or petrol engines, hydraulic motors, gas turbines or electric motors.
Block Diagram of Electric Drive
The below figure shows the block diagram of the electric drive. The load mentioned in the block diagram can be any kind of equipment that has an electric motor like washing machine, fans, etc.
Various Parts of Electrical Drive
The main parts of the electrical drives are power modulator, motor, controlling unit and sensing units.
The power modulator regulates the output power of the source. It controls the power from the source to the motor in such a manner that a motor transmits the speed-torque characteristic required by the load.
During the transient operations like starting, braking and speed reversing the excessive current drawn from the source. This excessive current drawn from the source may overload it or may cause a voltage drop.
Hence the power modulator restricts the source and motor current. The power modulator converts the energy according to the requirement of the motor e.g. if the source is DC and an induction motor is used then the power modulator converts DC into AC.
It also selects the mode of operation of the motor, i.e., motoring or braking.
The control unit controls the power modulator which operates at a small voltage and power level. The control unit also operates the power modulator as desired.
It also generates commands for the protection of power modulators and motor. An input command signal which adjusts the operating point of the drive, from an input to the control unit.
It senses a certain drive parameter like motor current and speed. It mainly required either for protection or for closed-loop operation.
What are the Types of Electrical Drive?
Electrical drives are classified as;
- Group drive
- Individual Drive
- Multi motor drive
In addition to these drives are further classified,
Based on Supply
- AC drives
- DC drives
Based on Running Speed
- Constant speed drive or single speed Drives
- Variable speed drives
Based on a Number of Motors
- Single motor drives
- Multi motor drives
Based on Control Parameter
- Constant Torque drives
- Constant Power drives
Where the Electrical Drive is used?
The application of electric drive includes;
- It used as electric traction. This is the main application where an electric drive used. There are many types of electric tractions includes electric trains, buses, trolleys, trams, and nowadays solar-powered vehicle used for transportation.
- It used in industries like rolling mills, textile mills, fans, paper machines, machine tools, pumps, robots. The drives are used in the application where precise control of motion required.
- The petrol and diesel engines, gas turbines, hydraulic and electric motors replaced with the electric drive.
- It used to get a wide range of speed, torque and power.
- The lifespan of electric drive high than other drives systems.
- It uses electrical energy. Therefore, it is pollution-free.
- Various speed control methods are available.
- It requires less space to install.
- It can controlled using remote and operate using the software.
- Economical and reliable
- It has high efficiency
- It used instead of mechanical drives that use fossil fuels. So, it decreases the use of fossil fuels.
- The initial cost of the drive is very high.
- It has a poor dynamic response.
- It causes noise pollution.
- The electric drive system cannot work on the failure of the electrical supply.
- It cannot install where electricity is not available.
- The system may get damaged during the breakdown of conductors or short circuits.