An electric lawnmower clutch, commonly called a power takeoff clutch (PTO), is the part of a lawnmower or riding tractor responsible for engaging the blade. The electric clutch helps to transfer engine power to the drive train. The clutch connects two drive shafts and is controlled by a toggle switch. PTO clutches work in conjunction with the PTO drive shaft and must be compatible with the transmission of the lawnmower.
An electric lawnmower clutch gets energy from the mower's engine and transfers it to the mower blade. An electric clutch also performs the function of a brake to stop the blades when the PTO gets turned off. Some lawn mower manufacturers suggest the purchase of a PTO over running clutch. This type of clutch prevents the mower from moving after the driver disengages the mower clutch.
An electric clutch is technically an electromagnetic apparatus. Inside the disc shaped clutch is a magnetic coil. When the clutch receives power from the starter, the magnetic coil forces an armature into contact with the rotor. The rotor is attached to the crankshaft, and as the armature begins to spin it will turn a pulley that spins the mower's blades. For larger mowers or small tractors that have more than one blade set, electric clutches can work in conjunction with the drive assembly to operate the blade sets at different speeds.
When the power to the electric clutch turns off, the magnetic energy releases control of the armature. At that point, the springs that control the armature's movements force it back against the brake. The brake then stops the pulley, which turns off the mower's blade. The electric mowing clutch can turn off the rotation of the blades without affecting the running of the engine. This is how drivers can ride a mower a long distance without having to worry about hitting spinning blades on protruding rocks or other objects in the grass.