We need to ensure that the capacity of the converter matches. First, correctly select the type of frequency converter according to the negative. 

The selection of frequency converter shall be based on the actual motor current value, and the rated power of motor can only be used as reference. Secondly, we should fully consider that the output of the converter contains high harmonics, which will lead to the power factor and efficiency of the motor.

Voltage matching: the rated voltage of the frequency converter is consistent with the rated voltage of the motor.

Current matching: for ordinary centrifugal pump, the rated current of frequency converter is consistent with that of motor. For special loads such as deep water pumps, it is necessary to refer to the motor performance parameters to determine the current and overload capacity of the converter with the maximum current. The current setting of the frequency converter shall not be less than 1.1 times of the rated current of the motor, and the maximum current is generally 1.5 times of the rated current of the motor.

About one dragging Multiple:

One drive multiple is a frequency converter with multiple motors. The capacity of the frequency converter is the sum of the capacity of multiple motors (based on the current), and it is better to amplify 10%~15%. At the same time, it is necessary to ensure that each motor has the appropriate load and power, neither idling nor overload, and perform its own duties, cooperate with each other, and live in peace; But the control is not good. Some are heavy, some are light, some are tired, and some are idle. As a result, the overloaded motor was heated and the whole system was paralyzed. Therefore, when you delay too long, you must be careful.

Then, on the other hand, drag one more, and multiple frequency converters with one motor. The answer is absolutely forbidden!

About cables

If the converter needs long cable operation, measures shall be taken to suppress the influence of long cable on ground coupling capacitance to avoid insufficient output of the converter. Therefore, in this case, the capacity of the converter should be enlarged by one gear or the output reactor should be installed at the output end of the converter. When the frequency converter is used to control the parallel motor, it must be considered that the sum of the cable length from the frequency converter to the motor is within the allowable range of the frequency converter. 

Special applications.

1. For example, high ambient temperature, high switching frequency, high altitude, etc., will cause the converter to reduce its capacity at this time, and the converter needs to enlarge the first gear selection. 

2. When the frequency converter is used to drive the high-speed motor, the output current value increases due to the small reactance of the high-speed motor. Therefore, the capacity of high-speed motor frequency converter is slightly larger than that of ordinary motor. 

3. When the explosion-proof motor is driven, the frequency converter has no explosion-proof structure, and the frequency converter should be set outside the hazardous area. 

4. When selecting the frequency converter, be sure to pay attention to whether its protection level matches the site conditions.

other

1. When the frequency converter drives the wound rotor asynchronous motor, the existing motor is mainly used. Since overcurrent tripping caused by ripple current is easy to occur, frequency converter with slightly larger capacity than usual should be selected. 

2. When the compressor, vibrator and other loads with large torque fluctuation and the oil pump have peak load, the power frequency operation shall be understood, and the frequency converter with rated output current greater than its maximum current shall be selected. 

3. When the frequency converter controls the Roots blower, due to the large starting current, it is necessary to pay attention to whether the capacity of the frequency converter is large enough when selecting the frequency converter. 

4. When using the frequency converter to drive the gear reduction motor, the range of use is limited by the lubrication method of the gear rotation part. Do not exceed the maximum speed allowed. 

5. Inverter drive is not applicable to single-phase motor. 

The influence of the distance between the frequency converter and the motor on the system and the measures. 

At the industrial use site, the distance between the frequency converter and the motor can be roughly divided into three situations: source distance, medium distance and short distance. Within 20m is short distance, 20-100m is medium distance, and above 100m is long distance.

The distance between the frequency converter and the motor is within 20m, which can be directly connected with the frequency converter;

The medium distance between the frequency converter and the motor is 20m to 100m, so the carrier frequency of the frequency converter needs to be adjusted to reduce harmonics and interference; For the long distance connection of more than 100m between the frequency converter and the motor, not only the carrier frequency should be moderately reduced, but also the output AC reactor should be installed.