DC Motor are used when the speed and torque is required over a wide range. One method to controlling is by changing the terminal voltage. The study involves the electrical transient in the armature circuit and the mechanical transients in the mechanical systems. To perform the simulation of the system, an appropriate model needs to be established. Therefore, a model based on the motor specifications needs to be obtained.
..............(1)
...............(2)
where,
Laplace Transform Eqn (1) and (2),
...............(3)
...............(4)
When switch closed ( electrical equation ),
...........(5)
Laplace Transform eqn (5),
where,
, is the electrical time constant of the armature.
Dynamic equation for mechanical system (mechanical equation)
..........(6)
where,
, the rotational loss torque of the system.
, equivalent viscous friction constant of load and motor.
, mechanical load torque.
, combined moment of inertia ( motor + load).
Laplace Transform of eqn (6),
...(7)
Manipulating eqn (7),
where,
, is the mechanical time constant.
From the circuit,
....(8)
....(9)
A block diagram representation from equation (8) and (9).
