Inverter with load test run

- Dec 20, 2017 -

1. Manual operation

Inverter panel stop button to observe the motor stops running process and the inverter display window to see if there is any abnormal phenomenon.

2. If the inverter starts to stop when the motor overcurrent protection operation, should be re-set acceleration and deceleration time. The acceleration of the motor during acceleration and deceleration depends on the acceleration torque, while the frequency change rate of the inverter during startup and braking is set by the user. If the motor inertia or motor load change, according to the pre-set rate of change when the speed increase or deceleration, there may be insufficient acceleration torque, resulting in stalling the motor, that is, the motor speed and inverter output frequency is not coordinated, resulting in Current or over voltage. Therefore, it is necessary to properly set the acceleration and deceleration time according to the motor's moment of inertia and load, so that the frequency change rate of the inverter can be coordinated with the rate of change of the motor speed. Check whether this setting is reasonable or not, according to the experience of the first choice of acceleration and deceleration time to set, if there is over-current during the start-up process, may be appropriate to extend the acceleration time; if the overcurrent during braking, Appropriate to extend the deceleration time. On the other hand, Canada, deceleration time should not be set too long, too long will affect the production efficiency, especially frequent Kai, braking.

3. If the frequency converter is still protected for a limited period of time, change the start / stop operating curve from straight to S-shaped, U-shaped or S-shaped and U-shaped. When motor load inertia is large, a longer start-stop time should be used and the type of operating curve set according to its load characteristics.

4. If there is still a running fault in the drive, try increasing the protection value for the maximum current, but you can not cancel the protection. Leave a margin of at least 10% -20%.

5. If the inverter is still operating fault occurs, should be replaced by a higher level of power inverter.

6. If the inverter drives the motor less than the preset speed during start-up, there may be two situations:

(1) Electromechanical resonance occurs in the system and the sound from the motor can be judged. By setting the frequency hopping value, you can avoid the resonance point. General inverter can set three jump points. When the V / f controlled inverter drives an asynchronous motor, the motor current and speed will oscillate in some frequency segments, and the system will not run in severe frequency. Even if overcurrent protection occurs during acceleration, the motor can not start normally. When the motor Light load or moment of inertia is more serious. Common frequency inverters are equipped with frequency hopping function. Users can set the crossover point and cross-hop width on the V / f curve according to the frequency point where the system oscillates. When the motor accelerates, you can automatically skip these frequency segments to ensure the system can work normally.

(2) The torque output capacity of the motor is not enough. The factory parameters of different brands of inverters are set differently. Under the same conditions, the load capacity may be different due to different control methods of the inverter, resulting in different loading capacities of the motors; or Due to the different output efficiency of the system, resulting in load capacity will vary. In this case, you can increase the value of torque boost. If it can not reach, you can use manual torque boost function, do not set too large, the motor temperature increase at this time. If still not, should use the new control methods, such as Hitachi inverter V / f ratio of a constant method, start less than the requirements, the sensorless space vector control instead, it has a greater torque output ability. For fan and pump loads, reduce the torque curve.

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