High Power Electric Appliance for Battery Forklift

Battery forklifts have come into general use because they can meet the requirements for using many kinds of energy to cope with the rising prices of petroleum and for improving the working environments. Along with this trend, there is a strong demand for battery forklifts which operate as fast as engine-driven ones. To realize these requirements by the conventional technology, it is inevitable that the increased power and braking current will need a larger traction motor and the temperature rise caused by commutator sparks induced by plugging will also need a larger traction motor. In order to reduce the size and weight of the traction motor by reducing the temperature rise, we have developed a high-power traction motor with a built-in fan motor which turns independently of the rotation of the motor, and we have also developed a controller with regenerative braking which charges a part of braking energy into the battery, reducing the temperature rise of the motor. By combining the two devices, it was possible to attain as good driving performance as engine-driven forklifts and to lengthen the operating time by 10% in the operation mode in which starting and stopping with regenerative braking were repeated.