What Is the Function of the Gearbox in an Explosion-Proof Battery Electric Locomotive?

An explosion-proof battery electric locomotive is equipped with a gearbox, which reduces the motor speed through a transmission system before driving the wheelsets. But why is a gearbox necessary? Is it just for reducing speed? Why not directly control the motor speed or use a low-speed motor instead?

The gearbox’s role is not just to lower speed, and reducing speed itself is not the sole purpose. The motor in an explosion-proof battery electric locomotive runs at high speed but produces low torque, while the locomotive requires high torque for operation, especially when transporting heavy loads. If a variable frequency motor operates at low speed, it not only provides insufficient torque but also generates excessive heat. Therefore, the gearbox is crucial as it reduces speed while simultaneously increasing torque.

Additionally, the gearbox protects the motor by providing a sealed working environment for the drive shaft. It also reduces the stress on the motor during overload conditions, prolonging the motor’s lifespan.

This is why an explosion-proof battery electric locomotive must use a gearbox—to enhance torque, ensure stable operation, and protect the motor from excessive stress.