What is an Electric Drive?
An electric drive is an electromechanical system that converts electric energy into mechanical energy of the driven machine. Otherwise, drives that use the electric motor as prime mover are known as electric drives.
An electric drive includes motor, a mechanical transmission gear, power processor and controller. The motor is the electromechanical converter. The gear system transforms the mechanical energy to load work in accordance with the actuator work. The controller compares the setpoint value and the current value.
Components of Electric Drives:
Motor:
The motors obtain energy from electrical sources. They convert the energy from electrical to mechanical, so they can be considered as energy converters. There are several types of motors that are used in electric units; The choice of the type of use depends on the application and the available sources. They are basically classified as DC and AC motors.
Source:
The electrical sources or the power supplies provide the power to the electric motor. For a high-efficiency operation, the power obtained from the sources must be regulated using electronic power converters. The source can be both AC or DC.
Power Modulator:
Since electrical sources are generally uncontrollable, therefore, it is necessary to be able to control the flow to the motor; This is achieved through the use of a power processor or a power modulator. With controllable sources, the motor can be inverted, braked or operated with variable speed.
Control Unit:
There are types of control unit, Analog, digital and microprocessor-based control unit. The analog unit is less noise immune compared to the other two systems.
The digital control unit has features immune to noise, configurable, bandwidth depends on sampling frequency. The microprocessor control unit is more flexible with lower bandwidth compared to above.
Wiring consideration for Drive system:
While the installation of motor power cables needs to be considered for any EMI and RFI effects, other factors must also be considered if the separation of the motor and drive is excessive. In the selection of a motor, the following points should be considered:
-
If the drive is to be retrofitted to a motor with unknown insulation specifications, this problem can only be resolved by consultation with the supplier of the original motor, and it may require replacement of the motor by a motor with enhanced insulation capabilities.
-
To ensure safety of operators and other personnel by limiting touch voltages to safe values, by provide a low resistance path for fault current so that the circuit protective devices operate rapidly to disconnect the supply. The resistance of the earth path must be low enough so that the potential rise on the earth terminal and any metalwork connected to it is not hazardous.
-
To ensure correct operation of the electricity supply network and ensure good power quality
Advantages of Elecric Drives:-
-
Easy to control
-
Wide ranges of speed
-
High efficiency
-
Clean operation
-
Easy to store or transport energy