From operating engine run/stop levers, throttles, chokes, valves and clutches to protecting expensive diesel engines from over-speed, low tube pressure and high temperature, you can rely on Woodward solenoids to meet the ever-changing technical demands of modern industry. The Woodward Dual Coil Solenoid: To allow a solenoid to be held energised for long periods of time without overheating, Woodward uses two separate coil windings instead of one. The first wound coil operates at a high current level to provide maximum pull or push. The second wound coil simply holds the plunger in place after it has completed its stroke and "bottomed out". Since the current required to hold the plunger in place is low, dual coil solenoids can be energized continuosly without overheating. This unique design concept results in a highly efficient compact solenoid approximately one half the size of a comparable single coil unit.