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The SPI failure of the English wittenet inverter
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The G120 frequency converter is controlled by one pull and two pull. What parameters need special attention or modification? Using one frequency converter to drive multiple motors requires the following considerations:
Type selection of frequency converter:
1) Estimate the rated output current of the frequency converter according to the total rated output current of the motor.
2) According to the estimated rated output current of the converter, the margin of the converter should be increased appropriately.
Motor protection:
1) Overcurrent protection and overload protection are installed separately in each motor circuit.
2) Because the output voltage waveform of the frequency converter is pulse width modulation wave, it will cause additional heat of the protective device. It is necessary to consider the selection margin of the protective device in order to prevent frequent protective tripping of the motor.
3) Install over-temperature protection for each motor.
III. Limitations
1) The total length of all motor cables should not exceed the permissible range of the converter.
2) In the case of over-long motor cables, it can be considered that the output of the converter is connected to the site by a bus, and then the line is divided to each motor after arriving at the site.
3) It is recommended to install the reactor on the output side of the converter.
4) Frequency converter usually adopts V/F control mode.
5) All motors are required to start and stop at the same time.
6) In the operation of frequency converter, the switching operation of motor is generally not allowed.
The building mainly realizes the control of G120 converter with one pull and two pull. The control mode of converter should choose V/F control P1300=0 instead of vector control. The parameters of two motors are as same as possible, that is, the same manufacturer produces (the same motor nameplate), and the frequency converter outputs to each motor with a motor protector or thermal relay.
There are two methods for setting parameters of frequency converter motor and fast debugging.
**, rated current parameter of converter P305 = rated current value of single motor * 2; rated power parameter of converter P307 = rated power value of single motor * 2; number of parallel motors P306 = 1 (default)
Secondly, the rated current parameter of frequency converter P305 = rated current value of single motor; the rated power parameter of frequency converter P307 = rated power value of single motor; the number of parallel motors P306 = 2
Above is what should be paid special attention to when the G120 converter is controlled by one pull and two pull. Other parameters are the same as when controlling the V/F control of a single motor.
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