F11/F12 Fan motors
F11/F12 motors, in frame sizes -5 to -40 cc, are common in Fan applications. Some typical options are, built in check valve, pressure relief valve, cartridge flange and tapered shaft (refer to the schematic to theright).
The fan motor can be operated at very high speeds without reliability problems. The fan is usually installed directly on the motor shaft without additional bearing support. The F11/F12 has up to 95% overall efficiency which reduces the diesel consumption and minimizes the cooling demand.
F11/F12 in saw motor applications
Series F11/F12 motors have proven suitable for demanding applications such as chain saws. Primarily due to the 40° bent-axis design, spherical pistons (with laminated piston rings) and gear synchronization, very high speeds are permissible. Not even low temperatures at start-up affect reliability. Because of the built-in anti cavitation valve, either left hand (L) or right hand (R) rotation must be specified
when ordering the motor. When the pump flow to the motor is shut off and the motor is operating at very high speeds, it is important that sufficient return port back pressure is available. The anti cavitation valve will then open and direct flow to the motor inlet port. If the inlet pressure is insufficient, motor cavitation will be experienced.
To further enhance the saw function and, at the same time, reduce weight, cost and installation dimensions,
a specific saw motor has been developed (frame sizes F11-6, -10, -12, -14, -19, F12-30 and -40; refer to the illustration to the right) which is specifically dedicated to bar saws. The motor allows the saw bar bearings to be mounted directly on the motor housing, and the sprocket installs on the motor shaft without additional bearings.