Wirewound Precharge Resistors

A pre-charge resistor is a device that slowly charges the capacitors inside a electronic speed controller before it is powered up. Without this resistor, closing the contactor would generate a large amount of inrush current causing the contacts to arc. This arcing can permanently weld the contacts in the "on" position. The inrush current from not pre-charging can also cause the contact tips to get pitted resulting in a poor connection and diminish vehicle performance.