The safety valve on the rotary motor of the excavator for construction machinery is damaged and the rotary safety pressure value of the main valve is too low, which may result in weak rotation of the excavator.

　　In the actual operation of excavator, if LS oil pipe is inverted, the small excavator will not only weaken the excavator, but also slowly rotate the arm or boom and bucket.

　　1. Check whether the working device speed, overflow pressure value and stroke overflow pressure value of excavator are within the specified range.

　　2. Then check whether the oil pressure of the excavator drive motor is normal.

　　3.If not, the fault is due to insufficient oil supply to the excavator drive motor.

　　Reduce unnecessary power loss.

　　1. Proper use and protection of exhaust pipes and mufflers, including frequent removal of coke from the mufflers, timely repair of damaged mufflers, no forward installation of exhaust pipes, no need for homemade fineness and longer exhaust pipes, etc.

　　2. Keep the excavator's walking system in good condition.

　　3. Enhance the protection and maintenance of excavator brake system, especially to prevent brake "stagnation" and small excavator fire, i.e. brake friction disc contacting brake drum in non-braking state. A simple way to determine brake "stuck" is to touch the brake drum by hand.

　　4.When a locomotive with power steering makes a sharp turn, loosen the steering wheel slightly after turning to the * limit position so that the spool valve of the distribution valve can return to neutral position.Otherwise, if the high oil pressure of the hydraulic system lasts too long, it will cause excessive engine power consumption and increase wear on the parts.