Contents
How can the starting current of a DC motor be limited?
To prevent such an incidence from occurring several starting methods of DC motor has been adopted. The main principal of this being the addition of external electrical resistance Rext to the armature winding, so as to increase the effective resistance to Ra + Rext, thus limiting the armature current to the rated value.
How can I reduce my high inrush current?
Inrush current can be reduced by increasing the voltage rise time on the load capacitance and slowing down the rate at which the capacitors charge. Three different solutions to reduce inrush current are shown below: voltage regulators, discrete components, and integrated load switches.
What happens when you start a DC motor?
While starting the DC motor, it draws the heavy current which damages the motor. The starter reduces the heavy current and protects the system from damage. The dc motor has no back emf. At the starting of the motor, the armature current is controlled by the resistance of the circuit.
How does current limiting work on a DC motor?
When motor power comes on to close the valve the RC circuit begins to climb until it surpasses the reference voltage. When it times out it can shut off motor current. With a little thought you can further expand the circuit so that it holds itself off until you manually reset the system so as to open the valve electronically as well.
When do you add resistance to a DC motor?
At the time of starting of all DC Motors, except for very small motors, an extra resistance must be connected in series with the armature. This extra resistance is added so that a safe value of the motor is maintained and to limit the starting current until the motor has attained its stable speed.
What are the problems of high starting current?
Such high starting current of DC motor creates two major problems. Firstly, current of the order of 400 A has the potential of damaging the internal circuit of the armature winding of DC motor at the very onset.