Servo motor failure analysis - Delixi

Three-phase communication servo motors are widely used, but after long-term operation, various problems will occur. Timely identification of the cause of the fault and corresponding treatment is an important task to prevent the spread of the fault and ensure the normal operation of the equipment.

Servo motor failure analysis - Delixi

1. Motor encoder alarm

1. Causes of the problem

(1) Wiring fault;

(2) electromagnetic interference;

(3) Encoder hardware damage caused by mechanical oscillation;

(4) Pollution caused by the on-site environment;

2. Fault cleaning

(1) Check the wiring and sweep away the fault;

(2) Check whether the shielding is in place, check whether the wiring is reasonable and handled, and add filters to improve if necessary;

(3) Check the mechanical structure and improve it;

(4) Check whether the encoder is polluted or corroded (dust, oil, etc.) and strengthen protection;

3. Installation and wiring standards

(1) Use the original cable as much as possible;

(2) Separate the cable to keep it away from the polluted wiring as much as possible, especially the highly polluted wiring;

(3) Always use the internal power supply as much as possible. If a switching power supply is used, a filter should be used to ensure that the power supply reaches the cleanliness level;

(4) Always ground the common end;

(5) Keep the encoder housing insulated from the machine structure and connected to the cable shield;

(6) If it is not possible to insulate the encoder, the cable shield can be connected to the ground (or special terminals) on the encoder housing and driver frame.

Second, the motor shaft is broken

1. Causes of the problem

(1) Unreasonable mechanical design leads to excessive radial load force;

(2) The load end is stuck or severely overloaded;

(3) The motor and reducer are not centered when assembling.

2. Fault cleaning

(1) Check the maximum radial load force that can be borne in the motor sample and improve the mechanical design;

(2) Check the operation status of the load side, confirm the process requirements of the practice and improve them;

(3) Check whether the load operation is stable, whether there is vibration, and improve the accuracy of mechanical assembly.

3. The no-load current of the motor is unbalanced, and the three-phase difference is large

1. Causes of the problem

(1) The end of the winding is wrongly connected;

(2) The power supply voltage is unbalanced;

(3) There are problems such as inter-turn short circuit and reverse coil connection in the winding.

2. Fault cleaning

(1) Review and correct;

(2) Measure the power supply voltage and try to eliminate the imbalance;

(3) Eliminate winding problems.

Fourth, the motor is running when the sound is abnormal, there is abnormal noise

1. Causes of the problem

(1) The bearing is worn or there are foreign substances such as sand particles in the oil;

(2) The rotor core is loose;

(3) Lack of oil in the bearing;

(4) The power supply voltage is too high or unbalanced.

2. Fault cleaning

(1) Replace bearings or clean bearings;

(2) Overhaul the rotor core;

(3) Refueling;

(4) Check and adjust the power supply voltage

5. It is difficult to start the motor, and when the rated load is loaded, the speed of the motor is much lower than the rated speed

1. Causes of the problem

(1) The power supply voltage is too low;

(2) Misconnection of the motor by the face connection method;

(3) Rotor welding or cracking;

(4) The coil of the rotor part is misconnected or reversed;

(3) Excessive number of turns added when correcting the motor winding;

(5) Motor overload.

2. Fault cleaning

(1) Measure the power supply voltage and try to improve;

(2) correction of connections;

(3) Check the open welding and breaking points and correct them;

(4) Correct the misconnection if it is found;

(5) the correct number of turns of rehabilitation;

(6) Load shedding.

6. The motor cannot rotate after being energized, but there is no abnormal noise, no peculiar smell and smoke?

1. Causes of the problem

(1) The power supply is not connected (at least two phases are not connected);

(2) Fuse blowing (at least two-phase blowing);

(3) The overcurrent relay is adjusted too small;

(4) The wiring of the control equipment is faulty.

2. Fault cleaning

(1) Check whether there is a break point at the power circuit switch, fuse and junction box, and correct it;

(2) Check the fuse model, the cause of the fuse, and replace the fuse;

(3) Adjust the setting value of the relay and cooperate with the motor;

(4) Correct the wiring.

7. The motor oscillates greatly during operation

1. Causes of the problem

(1) Because the gap of the worn bearing is too large;

(2) uneven air gap;

(3) Rotor imbalance;

(4) Twists and turns of the shaft;

(5) The coaxial axis of the coupling (pulley) is too low.

2. Fault cleaning

(1) Overhaul the bearing and replace it if necessary;

(2) Adjust the air gap to make it uniform;

(3) Calibrate the dynamic balance of the rotor;

(4) Straighten the rotating shaft;

(5) Proofread from scratch to make it conform to the rules.

8. There is a humming sound when the motor does not rotate after power-on

1. Causes of the problem

(1) There is an open circuit in the rotor winding (one-phase disconnection) or one-phase power loss of the power supply;

(2) The beginning and end of the winding lead wire are connected incorrectly or the winding is reversed;

(3) The contact of the power supply circuit is loose and the touch resistance is large;

(4) The motor is overloaded or the rotor is stuck;

(5) The power supply voltage is too low;

(6) The assembly of the small motor is too tight or the grease in the bearing is too hard;

(7) The bearing is jammed.

2. Fault cleaning

(1) Identify the breakpoints and correct them;

(2) Check the winding polarity; Determine whether the end of the winding is correct;

(3) Tighten the loose wiring screws, use a multimeter to determine whether the joints are falsely connected, and correct them;

(4) load shedding or detecting and eliminating mechanical faults;

(5) Check whether the face connection method of the rule is wrong; Whether the voltage drop is too large because the power supply wire is too thin, and corrected it;

(6) Assemble from scratch to make it flexible; Replacement of qualified greases;

(7) Correct the bearing.

9. Bearing overheating?

1. Causes of the problem

(1) Too much or too little slippery grease;

(2) The oil quality is not good, and it contains impurities;

(3) Improper cooperation between the bearing and the journal or end cover (too loose or too tight);

(4) The inner bore of the bearing is painful and rubs with the shaft;

(5) The motor end cover or bearing cover is not flattened;

(6) The coupling between the motor and the load is not calibrated, or the belt is too tight;

(7) The bearing clearance is too large or too small;

(8) The motor shaft is tortuous.

2. Fault cleaning

(1) Add smooth grease (1/3-2/3 of the volume) according to the rules;

(2) Replace the clean smooth grease;

(3) If it is too loose, it can be corrected with a binder, and if it is too tight, it should be turned tightly, and the inner hole of the shaft journal or end cover should be ground to make it suitable;

(4) Repair the bearing cover and eliminate the friction point;

(5) De novo assembly;

(6) Proofread from scratch and adjust the belt tension;

(7) Replace the new bearing;

(8) Calibrate the motor shaft or replace the rotor.

10. The motor is overheated or even smoked?

1. Causes of the problem

(1) The power supply voltage is too high;

(2) The power supply voltage is too low, the motor is running with rated load, and the current is too hot for the winding;

(3) When repairing and dismantling the winding, the thermal dismantling method is improperly selected, which burns the iron core;

(4) The motor is overloaded or starts frequently;

(5) The motor lacks phase and runs in two phases;

(6) After rewinding, the winding impregnation paint is insufficient;

(7) The ambient temperature is high, and there is a lot of dirt on the surface of the motor, or the ventilation duct is blocked.

2. Fault cleaning

(1) Reducing the power supply voltage (such as adjusting the tap of the power supply transformer);

(2) Improve the power supply voltage or change the thick power supply wire;

(3) Overhaul the iron core and remove faults;

(4) load shedding; Operate the start according to the regular number of times;

(5) Rehabilitation three-phase operation;

(6) The secondary dipping and vacuum dipping process are selected;

(7) Clean the motor, improve the ambient temperature, and choose the cooling method.

Servo motor failure analysis - Delixi

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