Why can't electric chain hoist work continuously for a long time

I believe that when you buy an electric chain hoist, you will be told that the electric chain hoist cannot work continuously for a long time. It implements a work system. The working mode of the electric chain hoist motor is S4 (intermittent), which roughly means working for a while and taking a break. Why is this?

Although the electric chain hoist is an iron product, it has long been out of flesh and blood. As a device that helps people to lift and carry, it cannot speak, but the tools are also limited. The working time limit of electric chain hoist depends on its motor. The motor of the electric chain hoist is just like an ordinary worker. Although it lacks a lot of perception compared to a real person, one thing that is indistinguishable from an ordinary person is that the motor itself will be "tired". If the motor is continuously used for too long or brakes frequently at this time, the motor will continue to heat up, and there will be a risk of burnout. Just like a person with a high fever, a continuous high fever will burn the brain, and the motor will burn the internal parts.

Therefore, when the electric chain hoist is used, it should be ensured that the continuous operation rate of the motor during each work period shall not exceed 40%, and the braking frequency shall not exceed 4 times per minute. The work system of the safety electric chain hoist should be strictly carried out.

Why can't electric chain hoist work continuously for a long time