Why Does the Friction Torque Limiter Slip When the Scraper Conveyor Jams?0

During operation, the scraper conveyor may jam due to coal accumulation, foreign matter entry and other causes, leading to a sudden rise in load. The motor keeps outputting power, the resistance torque on the load side increases, and the torque in the transmission system keeps rising, which brings heavy impact to transmission components such as the reducer, sprocket assembly and scraper chain. The friction torque limiter is a key component for overload protection under such abnormal working conditions.

The friction torque limiter is generally installed between the motor and reducer, serving as an important protection link in the power transmission chain.

1. Stable power transmission under normal load

Under normal operation, the motor transmits power through the friction torque limiter to the reducer and subsequent transmission parts. The friction pair stays engaged, transmitting power within the set torque limit, so the equipment runs normally.

2. Torque limiting starts once the set value is reached under abnormal load

When jamming occurs, the load surges and the torque of the transmission system rises accordingly. Once the transmitted torque reaches the preset torque limit of the friction torque limiter, relative sliding appears on the friction pair to limit the transmitted torque and prevent excessive torque from being further transmitted backward.

At this moment, a speed difference may occur between the driving end and driven end. The relative sliding of the friction pair consumes part of energy, reducing the impact on transmission components including the reducer, sprocket assembly and scraper chain.

3. Stop and inspect promptly after slipping

It should be noted that slipping of the friction torque limiter does not fully cut off power, and it cannot work continuously for a long time.

During slipping, the friction pair still transmits torque close to the limit value. Part of mechanical energy is released as frictional heat, raising the temperature of friction plates. Therefore, continuous slipping is not a normal operating state. The machine should be shut down in time to remove coal and foreign objects, and investigate the root causes of jamming and overload.

Henan Shuangzhi specializes in coal mining machinery and spare parts. Based on actual working conditions of scraper conveyors, we provide friction torque limiters and relevant technical support. For equipment with frequent jamming and overload, the transmission system shall be inspected and analyzed according to site conditions, and proper torque limiting protection shall be selected to reduce impact on transmission components under abnormal conditions.