Spindle Control of the Lathe
The spindle is controlled using frequency control of the stator's current coupling. This method is called sensorless vector control (vector control). This article describes in detail how to set up the frequency converter for a lathe.
Features of Frequency Converters
- Compact design
- Space-saving in the control cabinet
- Removable input/output terminals, control panel with parameter copy capability
- Easy installation and maintenance, improving production efficiency
- VFC & EFC 3610 — starting torque 100% at 15 Hz;
- VFC & EFC 5610 — starting torque 200% at 0.5 Hz
- Efficient cutting of high-strength metals, avoiding overloads at low speeds and current overloads, minimal braking time of up to 2 seconds
- High control accuracy, fast dynamic performance
- Quick response to uneven surfaces to maintain stability and cutting quality, as well as improving surface smoothness
- Re-excitation braking function allows reducing braking time (up to 50% of the set time) without the need for a braking resistor
Application in CNC Lathes
The VFC and EFC inverters provide spindle drive and implement continuous control, meeting various processing needs. The actual speed can reach ± 1 to 2 revolutions. Selecting open-loop vector control ensures high overload capacity and starting torque, facilitating rapid start and stop of the motor, increasing processing efficiency. Parameter C000 should be set to SVC vector control mode to enhance control accuracy. After entering the rated motor data, dynamic auto-tuning should be utilized (C101 = 2). Setting C015 = 660 V determines the DC voltage limit to activate the braking switch and dissipate energy during braking.
Setting Parameters of the Frequency Converter
| Parameter Code | Name | Set Value | Note |
| b000 | Access Settings | 2 | Additional parameters |
| C000 | Control Mode | 1 | SVC Vector Control |
| C015 | Braking Switch Turn-On Point | 660 | Brake operating point 660 V |
| C025 | Overvoltage Protection Mode | 2 | Resistive braking enabled |
| C101 | Motor Auto-Tuning | 2 | Auto-tuning with rotation |
| C105 | Rated Motor Power | - | Dependent on motor |
| C106 | Rated Motor Voltage | - | Dependent on motor |
| C108 | Rated Motor Frequency | - | Dependent on motor |
| C109 | Rated Speed Frequency | - | Dependent on motor |
| C221 | Torque Boost | 01 | Manual boost |
| E000 | Frequency Set Point Source | 2 | AI1 Analog Input |
| E001 | Start Command Source | 1 | Via digital inputs |
| E008 | Max Output Frequency | 100 | Dependent on requirements |
| E009 | Upper Frequency Limit | 100 | Dependent on requirements |
| E026 | Acceleration Time | 2 | Dependent on requirements |
| E027 | Braking Time | 25 | Dependent on requirements |
| E037 | Starting Frequency Hold Time | 0 | Instant START |
| E101 | X2 Input | 36 | Reverse Rotation |
| E173 | Max Frequency of Analog Curve 1 | 100 | Dependent on requirements |