The rated speed is irrelevant. Servo motors have a concept of stall torque, which is actually measured at 1 rpm. As long as your motor is of good quality and the overload during use is not severe and is within the tolerance range, there should be basically no impact.
The lifespan of an electric motor mainly depends on its bearings, which are among the shortest-lived components. If you install it with high precision and good concentricity, you can use it with confidence. If it does burn out, it's the driver's fault for not having temperature protection.
Do you know the lifespan of a servo motor?
The rotor of an AC servo motor is usually made into a squirrel-cage type. However, in order to make the servo motor have a wide speed range, linear mechanical characteristics, no "self-rotation" phenomenon and fast response performance, it should have the characteristics of high rotor resistance and low moment of inertia compared with ordinary motors.
Currently, there are two main types of rotor structures: one is a squirrel-cage rotor with high-resistivity conductor bars made of high-resistivity conductive material, which is made slender to reduce the rotor's moment of inertia; the other is a hollow cup-shaped rotor made of aluminum alloy with very thin walls, only 0.2-0.3 mm. To reduce the magnetic resistance of the magnetic circuit, a fixed inner stator is placed inside the hollow cup-shaped rotor. The hollow cup-shaped rotor has a very small moment of inertia, responds quickly, and runs smoothly, so it is widely used.
1. Wiring
Power off the control card and connect the signal cables between the control card and the servo. The following cables are mandatory: the analog output cable of the control card, the enable signal cable, and the encoder signal cable output by the servo. After verifying that the wiring is correct, power on the motor and the control card (and PC). The motor should not move at this point and can be easily rotated with external force. If not, check the enable signal settings and wiring. Rotate the motor with external force to check if the control card can correctly detect changes in motor position; otherwise, check the encoder signal wiring and settings.
2. Try the direction
For a closed-loop control system, if the direction of the feedback signal is incorrect, the consequences will be disastrous. Enable the servo via the control card. The servo should then rotate at a low speed; this is the so-called "zero drift." Most control cards have instructions or parameters to suppress zero drift. Use these instructions or parameters to see if the motor's speed and direction can be controlled. If not, check the analog wiring and control mode parameter settings. Confirm that a positive value results in the motor rotating forward and the encoder count increasing; a negative value results in the motor rotating backward and the encoder count decreasing. Do not use this method if the motor is under load and has limited travel. Do not apply excessive voltage during testing; below 1V is recommended. If the directions are inconsistent, modify the parameters on the control card or motor to make them consistent.
3. Suppress zero drift
In closed-loop control, zero drift can negatively impact control performance, and it's best to suppress it. Carefully adjust the zero drift suppression parameters on the control card or servo motor to bring the motor speed close to zero. Since zero drift itself has a degree of randomness, it's not necessary to require the motor speed to be absolutely zero.
Servo motors have the function of emitting pulses. So, for every angle a servo motor rotates, it will emit a corresponding number of pulses. This forms a response, or closed loop, with the pulses received by the servo motor. In this way, the system knows how many pulses were sent to the servo motor and how many pulses were received back. This allows for very precise control of the motor's rotation, thereby achieving precise positioning, which can reach 0.001mm.
DC servo motors are divided into brushed and brushless motors. Brushed motors are low in cost, simple in structure, have high starting torque, wide speed range, and are easy to control. However, they require maintenance, which is inconvenient (replacing carbon brushes), generates electromagnetic interference, and has environmental requirements. Therefore, they can be used in cost-sensitive general industrial and civilian applications.
