In the production process of high-speed automatic paper feeder, the paper belt tension control system is used frequently and has high working intensity, so the frequency of fault is also high.

　　1. Paper break: in the production process, as the diameter of the running paper roll becomes smaller, the tension of the paper tape increases, which makes the swing range of the floating roller larger (especially when the paper receiving signal is sent out to prepare for paper connection), the paper holder is prone to break.

　　Check the paper tape tension angle displacement potentiometer 1pot on the rotary support shaft, that is, pull the floating roller up and down under the condition of power failure. If the resistance value of the paper tape tension angle displacement potentiometer 1pot changes abnormally, it should be replaced immediately and calibrated again (when the floating roller is at the bottom, the DC voltage value of the tension angle displacement potentiometer 1pot should be 1.9V; When the floating roller is at the top, its DC voltage should be 7.5V).

　　2. The value in the tension display table remains unchanged: in the production process, when the automatic paper feeder is started up and increases in speed, the display value on the tension display table should increase to the set value with the increase of the machine speed, but the actual situation is that the value on the tension display table remains unchanged.

　　Check the speed encoder connected on the side of the paper pass roller of the paper stand. Generally, if the connecting rod of the fixed shaft of the speed encoder is broken, the PLC equipment of the paper carrier can not receive the speed signal in time, which makes the value of the tension display table abnormal. The connecting rod of the fixed shaft of the speed encoder should be re fixed.