Variable-frequency Drive (VFD) is a power control device that controls an AC motor by changing the frequency of the motor’s operating power by applying variable frequency technology and microelectronics. It mainly consists of a rectifier, filter, inverter, brake unit, drive unit, detection unit microprocessor unit, and so on. The inverter has many protection functions, such as over-current, over-voltage, overload protection, etc.
Frequency conversion and energy-saving frequency converters energy saving are mainly shown in the application of fans and pumps. In order to ensure the reliability of production, various production machinery in the design with power drive, are left with a certain amount of surplus. When the motor can not run under full load, in addition to the power drive requirements, the excess torque increases the active power consumption, resulting in a waste of electrical energy. For fans, pumps, and other equipment traditional speed control method is to adjust the inlet or outlet baffle, and valve opening to adjust the amount of air and water supply, its input power is large, and a large amount of energy consumption in the baffle, valve interception process. When using frequency conversion, if the flow rate is reduced, the speed of the pump or fan can be reduced to meet the requirements.
The main circuit of the inverter can be broadly divided into two categories: voltage type is the inverter that converts the DC of the voltage source into AC, and the DC circuit filter is capacitor; current type is the inverter that converts the DC of the current source into AC, and its DC circuit filter is an inductor.
Why does the voltage of the inverter change in proportion to the current?
The torque of an asynchronous motor is generated by the interaction between the flux of the motor and the current flowing in the rotor. At the rated frequency, if the voltage is certain and the frequency is only reduced, the flux will be too large and the magnetic circuit will be saturated, which will burn up the motor in serious cases. Therefore, the frequency and voltage should be changed proportionally, that is, the frequency should be changed while the output voltage of the inverter is controlled so that the flux of the motor can be maintained to avoid the phenomenon of weak magnetism and magnetic saturation. This control method is mostly used for fan and pump energy-saving inverters.
Programmable Digital Input: Provide 7 terminals that can support ON-OFF inputs, 1 terminal that can support high-speed pulse input and PNP, NPN
Programmable Analog Input: AI1 can accept input of -10V-10V, AI2 can accept input 0-10V or 0-20mA
Programmable Open Collector Output: Provide 1 output terminal (open collector output or high-speed pulse output)
Relay Output: Provide 1 output terminal
Analog Output: Provide 2 output terminals, whose output range can be 0/4-20mA or 0-10V, as chosen.
Main Control Function
Control Mode: V/F, Sensorless Vector Control (SVC), Torque control
Overload Capacity: 60s with 150% of rated current, 10s with 180% of rated current
Speed Adjusting Range: 1:100 (SVC)
Carrier Frequency: 1kHz – 15.0kHz
Frequency reference source: keypad, analog input, HDI, serial communication, multi-stage speed, simple PLC, and PID setting. The combination of multi-modes and the switch between different modes can be realized
PID Control Function
Simple PLC, Multi-Steps Speed Control Function: 16 stages speed can be set
Traverse Control Function
None-Stop when instantaneous power off
Speed Trace Function: Smoothly start the running motor
QUICK/JOG Key: User defined shortcut key can be realized
Automatic Voltage Regulation Function (AVR)
Automatically keep the output voltage stable when the input voltage fluctuates
Fault protections: Protect from over current, over voltage, under voltage, over temperature, phase failure, overload, etc.
Huanyang Inverter Manual
Huanyang VFD manual GT series
Using serial comms control from Mach3 by Matty Zee
The next two versions are by Joe, but incorporate the error messages and fault-finding chapter. The differences are in the size and style