(1) Why high-power compressors use high-voltage power supply: Users of the main motors of compressors above 30 cubic meters or 200KW usually require high-voltage power supply drive (commonly used high-voltage power supply voltages are 3000V, 6000V, and 10000V). The instantaneous current of the motor when starting is 5-8 times the rated current.
For example, when a 250KW motor starts, its starting current is 450*7=3150A. Such a large current has a great impact on the power grid. In addition, the voltage loss of the wire will also be very large. For example, if the line impedance is 0.02Ω and the power supply voltage is 380V, the power supply voltage loss at the moment of starting is 0.02*3150=63V, and the power grid voltage is only 317V at this time. If a 10,000V high-voltage power supply is used, the rated current of the same 250KW motor is <30A, the wire impedance is 0.1Ω, the starting current is 30×7＝210A, and the line voltage loss is only
0.1*210=21V. For a power supply voltage of 10,000V, the line loss is 21V, which does not need to be considered at all.
(2) Features of the high-voltage power supply control system of the Rodcom screw compressor:
● LCD Chinese display
● In addition to the local start and stop function, the compressor also accepts the remote DCS start and stop function
● The main motor uses a 10,000V high-voltage motor, and the start is achieved by the compressor electronic control to control the high-voltage start cabinet to open and close. The high-voltage motor is protected by the high-voltage cabinet for overload, overcurrent, and phase loss. The compressor electronic control and the high-voltage cabinet signal connection are both connected by switch dry contacts. Output contact capacity (AC 220V 5A)
● The compressor electronic control is set to monitor the temperature of the three-phase winding of the high-voltage motor, and is equipped with an over-temperature warning prompt and over-temperature trip function. The compressor electronic control is equipped with a high-voltage motor internal heating function to remove moisture from the motor and improve the motor insulation strength. (Note: heating is not allowed when the motor is running)
●Detection and control protection of multiple temperature points, the compressor electronic control is equipped with two sets of high-voltage motor bearing temperature monitoring, and has over-temperature warning prompts and over-temperature trip functions
●Highly integrated, high reliability, high cost performance
●RS-485 communication function