FAQ of our servo motor and drive

AC servo application FAQ

1. What should I do if the servo does not lock the axis?

Check if the drive servo enable signal is connected to pin 21 of CN1, or if the internal enable PN95 parameter is changed to 1.

2. The role and difference of a common encoder, a single-turn absolute encoder, and a multi-turn absolute encoder?

The number of pulses fixed by a common encoder in one revolution cannot be recorded. The motor stops at a certain angle within one revolution. The single-turn absolute encoder can record the stop angle of a certain circle within the circle except for the fixed number of pulses per revolution. Record the number of motor running cycles. The multi-turn absolute encoder can record the number of motor running cycles based on the single-turn absolute encoder, but it must have a built-in battery or other power supply.

3. How to choose the servo drive and motor?

Step 1: Determine the mechanical structure and calculate the load inertia (see the motor selection calculation table for details)

Step 2: Determine the load running speed and calculate the motor speed.

Step 3: Compare the motor inertia and load inertia, and determine whether to use the reducer or similar equipment in combination with the motor speed.

Step 4: Determine the motor and drive model with the maximum load converted to the motor shaft for less than 50 times the servo motor inertia.

4. What is the difference between a servo motor and a normal motor?

 The biggest difference between servo motors and ordinary motors is the motor rotor and feedback device. The surface of the servo motor rotor is affixed with a strong magnetic steel sheet, so the position of the rotor can be precisely controlled by the magnetic field generated by the stator coil, and the acceleration and deceleration characteristics are much higher than those of ordinary motors. The feedback device can accurately feedback the rotor position of the motor to the servo drive. The feedback devices commonly used in servo motors include optical encoders, rotary transformers, and the like.

5. Is the UVW phase of the servo drive output to the motor interchangeable?

 No, the servo driver to motor UVW connection is unique. Ordinary asynchronous motor input power supply UVW two mutual time change motor will reverse, in fact, the servo motor UVW any two mutual motor change will also reverse, but the servo motor has a feedback device, so the positive feedback will lead to the motor speed. The servo drive detects and prevents the flying car, so what we see after the UVW is connected to the wrong line is that the motor turns at an angle at a very fast speed and then alarms.

6. What is the reason why the servo motor runs with load and stops when it stops?

 The load inertia is too large to adjust the speed loop proportional integral time constant. When the inertia ratio exceeds 20 times, it needs to be solved by a reducer.

7. In normal use, the motor temperature is high due to the high start-stop frequency, so will the motor be damaged if used for a long time?

 The servo motor encoder will be damaged when it reaches 85 degrees Celsius or higher. Demagnetization occurs when the servo motor rotor temperature reaches 130 degrees Celsius or above. Because of the temperature difference between the servo motor and the inside of the servo motor, the internal temperature of the motor is about 130 degrees when the surface temperature of the motor body is 85 degrees Celsius. In the case where the servo motor starts and stops frequently, the servo motor temperature may be high. In this case, forced cooling measures must be taken externally, such as adding a cooling fan and canceling the internal regenerative resistor to install a larger power regenerative resistor externally.

8. When the servo test machine is powered on, the motor will vibrate and have a lot of noise. How to solve it?

 This phenomenon is caused by the driver's gain setting being too high, resulting in self-oscillation. Please adjust the parameters to reduce the rigidity of the system.

9. What should I pay attention to before servo operation?

1 Whether the power supply voltage is suitable, overvoltage will cause damage to the driver module; 2 Do not start to connect all the required wires, only connect to the most basic system, after running well, gradually connect.

10. Is there any problem with the servo motor working at rated speed for a long time?

 Each motor has a corresponding characteristic curve. The output torque of the servo motor above the rated speed is definitely less than the rated speed. In addition, the long-term operation of the mechanical part of the motor above the rated speed will be affected.

11. When the servo is working in the torque mode, if the motor is driven by an external force for a long time in the opposite direction to the output of the motor, will it cause damage to the motor?

 This operating condition does not cause damage to the motor. Will report that the bus voltage is too high

12. When the PLC controls the servo by pulse + direction, what is the reason that the motor can only transfer in one direction?

 The line error causes the driver to not receive the direction signal; 2 The driver accepts the optocoupler of the direction signal and burns out. The normal input voltage of this circuit is 5V. If the 12V or 24V pulse signal is accidentally connected, the direction signal is basically ON. The loop that receives the pulse is prone to burnout.

13. After the servo is powered on, the pulse motor does not run automatically.

 1. Ensure good protection grounding

2. The driver power input is input to the line L, and the N terminal uses filter filtering.

3. Connect 103 ceramic capacitors between Pul/Dir +-.