ATTENTION ENGINEERS: Inductor to limit inrush when starting an electric motor? Answered
The situation: I am using a contactor (like a big switch) to start a brushed permanent magnet DC motor. I am not using a motor controller. The motor is a Mars 0909 which draws 4.8 KW continuous and 15KW for 30 seconds
The problem: This current can cause arcing at the contactor which can erode the contactor's electrical contact points and perhaps stress the batteries or blow a fuse needlessly.
The goal: Reduce inrush while the motor starts up.
The question: My teacher suggested I use a large inductor in series with the contactor. Theoretically the inductor would resist the initial inrush of current and then its resistance would go way down. We looked around a bit and didn't find any motors in series with an inductor in series. Is there a reason why inductors an not typically in series with motors?
Is this something like a "Peterson coil" or an "arc suppression coil"?
Any idea what the formula would be to calculate the size of such a coil?