I. Typical Motors Requiring Control in Circular Looms and the Approach to Using the Inverter
In a circular loom, there are generally several main motors to consider:
- Main Weaving Motor (Main Motor)
- Used to drive the main shaft of the circular loom, weaving tubular fabric.
- This motor often requires relatively precise speed regulation to match the requirements of yarn density, tension, etc.
- It is recommended to use a vector-controlled inverter (i.e., VCD-2000 series full vector control) and perform motor parameter auto-tuning (dynamic or static) to ensure good low-speed torque output and speed accuracy.
- Winding/Pulling Motor
- Winds the woven fabric onto the take-up roller or provides a stable pulling force.
- This motor also usually requires adjustable speed capability to maintain a stable pull speed under different diameter/tension conditions.
- If constant tension is required, consider using the inverter’s built-in PID regulation function (function group P7) by detecting the tension sensor feedback signal to adjust speed automatically.
- Warp Feeding or Auxiliary Motor
- Used for feeding warp yarn, adjusting the yarn creel, or driving other auxiliary mechanisms. If it only requires simple speed changes or two to three speed stages, you can use the multi-speed function of the inverter (P3.26–P3.32) or simple external terminal switching.
Note: Whether each motor on the circular loom should be equipped with its own inverter depends on the production line requirements. This example focuses on a typical dual-inverter control plan for a “main weaving motor + winding motor.” If the equipment structure is simpler, you can equip only the main weaving motor with an inverter.
II. Hardware Wiring
The wiring approach and terminal names/functions mentioned below are based on standard designations in the VCD-2000 series inverter manual. If your model’s terminal labels differ slightly, please refer to the actual nameplate and manual.
1. Main Circuit (Power Supply) Wiring
- Connect the three-phase AC380V (or AC220V, depending on the model) power supply to the inverter input terminals R, S, T.
- If it is a single-phase model, connect only two wires (R, T) for single-phase 220V.
- The three output wires of the motor connect to the inverter output terminals U, V, W (ensure they match the U, V, W in the motor junction box; if the running direction is opposite the desired direction, swap any two motor leads or use the reverse command).
- PE terminal (ground): Ensure both the inverter and motor have reliable grounding, typically via a dedicated ground wire directly connected to the cabinet ground bus or welded to the plant protective ground.
- If a braking resistor is needed (for quick stopping or significant regenerative energy), connect one side of the resistor to the inverter terminal P+ (labeled “+” or “P”) and the other side to B (labeled “PB” or “DB”), and set the relevant braking parameters in the function codes (e.g., P2.05, P2.06, etc.).
2. Control Terminal Wiring — Example for Main Weaving Motor
Below is an ASCII-style diagram of a common “external terminal start/stop + analog potentiometer speed control + fault output” wiring configuration. If multi-speed, forward/reverse, PID regulation, etc. are required, you can adjust and expand upon this basic framework.
┌───────────────────────── VCD-2000 Inverter ──────────────────────────┐
│ Main Circuit: Control Terminals (CN2 etc.)│
│ ┌───────────┐ │
│ │ R S T │<--- 3-phase AC input (AC380V) │
│ │ │ │
│ │ U V W │---> Connect to Main Weaving Motor (M1) │
│ │ │ │
│ │ P+ B │---> Braking resistor here if needed │
│ │ PE (Ground)│---> Ground │
│ └───────────┘ │
│ │
│ Control Terminals Example: │
│ +24V ---[X1]---┐ (Example: X1 as forward FWD start command) │
│ ├---> COM │
│ +24V ---[X2]---┘ (Example: X2 as reset or jog, depending on need)│
│ │
│ (Speed Set via Potentiometer) │
│ 10V ---[Pot]--- VI │
│ Other end of Pot --- GND │
│ │
│ (Fault Relay Output) │
│ TA --- Relay NO Contact --- TB │
│ Connect to external alarm circuit or indicator; │
│ TA-TB closing indicates inverter fault, etc. │
│ Refer to P4.11 or similar for multi-function output setup │
│ COM (Digital Common) and GND (Analog Ground) are separate, each │
│ single-point grounded nearby. │
└──────────────────────────────────────────────────────────────────────┘
- Terminals X1–X6 can be assigned various functions in function codes P4.00–P4.07. In this example, X1 is set to “Forward Run” (FWD), and X2 can be set to “Reset/Stop” or “Jog,” etc.
- If you need both forward and reverse, assign X1 = FWD and X2 = REV.
- If you want to switch between panel (or PLC) control and external terminals, you can use multi-function terminals to implement “command channel switching” and “frequency channel switching” (assign codes 23, 24, etc. to P4.00–P4.07).
- If you need PID tension control, connect the tension sensor (4–20mA or 0–10V) to CI or VI, then configure the relevant PID parameters in P7.00–P7.33.
3. Winding/Pulling Motor Inverter Wiring
- The wiring principle is the same as for the main weaving motor. For constant tension winding, connect a tension sensor or pressure sensor output (4–20mA) to the inverter’s CI (or VI), and enable the PID function (P7.00=1).
- Usually, you need to set P7.01=0 (digital setpoint) or 1 (analog setpoint) and P7.02=0 (VI feedback) or 1 (CI feedback) accordingly. Then configure P7.05 to match the feedback reading for the desired tension.
III. Core Function Codes and Parameter Examples
Below are key configuration ideas to help you understand typical debugging requirements for circular loom applications. In actual production, adjust them according to the motor nameplate, process needs, and auto-tuning results.
1. Basic Motor Parameter Auto-Tuning (Group PA)
- PA.01: Motor Rated Power (kW)
For example, 5.5 kW → set 5.5 - PA.02: Motor Rated Voltage (V)
For a 380V motor → set 380 - PA.03: Motor Rated Current (A)
According to the nameplate, e.g., 11.3A - PA.04: Motor Rated Frequency (Hz)
Typically 50Hz - PA.05: Motor Rated Speed (rpm)
For example, 1420 rpm - PA.06: Motor Poles
For a 4-pole motor → set 4 - PA.00: Auto-Tuning Mode
- 1 = Dynamic auto-tuning (if the motor can be unloaded); press RUN to start.
- 2 = Static auto-tuning (if it cannot be unloaded).
2. Basic Operation Parameters (Group P0)
- P0.00: Run Command Channel
- 0: Keypad control
- 1: External terminal control (common usage)
- 2: Serial port (RS485) control
- P0.01: Frequency Reference Channel
- 0: Keypad potentiometer
- 5: External potentiometer (0–5V/0–10V)
- 6: Analog current (4–20mA)
- P0.03: Start/Stop Channel
- 0: Keypad start/stop
- 1: External terminal start/stop
3. Frequency/Current Reference Parameters (Group P1)
- If using a 0–10V external potentiometer, set P1.04 = 10.00.
- If using a 4–20mA signal, switch JP3 to “I” and configure P1.07 / P1.08 / P1.09 for the range limits.
4. Start/Stop and Braking (Group P2)
- P2.00 / P2.01: Acceleration/Deceleration Time
For instance, 3.0s to 5.0s, depending on the machine’s inertia. Since a circular loom has relatively large inertia, you can extend acceleration time appropriately to avoid overcurrent trips. - P2.05 / P2.06: DC Braking Start Frequency and Current
If you need a quick “spot brake” on stopping, you can enable DC braking; just avoid motor overheating.
5. Multi-Speed / Simple PLC (Groups P3 / P8)
If you want an inverter to achieve multiple speeds (e.g., low-speed threading, high-speed operation, inspection speed, etc.), combine the multi-function input terminals X1–X6 in different combinations to get multi-speed operation.
- P3.26–P3.32: Multi-speed frequencies 1–7
- P4.00–P4.07: Assign X1, X2, etc., as multi-speed terminals
For more complex sequencing, you can use the PLC function (Group P8) for automatic speed changes.
6. PID Closed-Loop (Group P7) (e.g., Tension Control Motor)
- P7.00: Enable PID Regulation → 1 = closed-loop
- P7.01: Setpoint Channel and P7.02: Feedback Channel
- Example: Setpoint channel = digital (0), feedback channel = VI (0) or CI (1).
- P7.05: Target Setpoint
- For instance, if the pressure sensor outputs 0–5V corresponding to 0–5 kg tension and you want to maintain 3 kg, set the voltage at 3 kg as your target.
- P7.11, P7.12, P7.13: PID Proportional, Integral, Derivative Gains
- Adjust on-site. Increasing P7.12 helps stability, reducing oscillations.
7. Protection and Fault Handling (Groups P5 / P6)
- Overcurrent, overvoltage, phase loss, stall, reversed phase sequence, etc., can be set via the P5 group thresholds. You can also check fault records in P6.
- To output fault signals to an external alarm indicator, set the function for TA, TB, or OC1 in P4.10–P4.11 to “Inverter Fault Output” or “Running Signal,” etc.
IV. Key Implementation Points
- Main Weaving Motor
- Start/Stop: If X1 = FWD with +24V → COM, closing X1 starts forward run, opening it stops. If reverse is needed, set X2 = REV.
- Speed Control: If using an external potentiometer, wire it to 10V, VI, GND. Then set P0.01=5, and P1.04=10.00 (or 5.00).
- Electronic Thermal Protection: After configuring PA.01–PA.06 for rated motor parameters, check P5.00–P5.04 for motor overload protection.
- Winding/Pulling Motor (if tension detection is involved)
- Connect the 4–20mA tension sensor signal to the inverter’s CI, set JP3 to “I.” Then set P7.00=1 (PID), P7.02=1 (CI feedback), P7.01=0 (digital setpoint) or otherwise, and P7.05 for the target tension value (converted from the sensor).
- Adjust PID parameters (P7.11, P7.12, P7.13) as needed. During actual winding, check changes in roll diameter, tension error, oscillations, etc., then fine-tune the PID.
- Multi-Speed / Manual Adjustments
- During setup or maintenance, you may need low-speed creeping, repeated jog, etc. You can set X3 or X4 to “Jog Run” or “Multi-Speed Selection,” and assign relevant frequency values (P3.06, P3.26–P3.32). During production, simply toggle the switch or foot pedal to switch speeds quickly.
- Fault Alarms and Safety Interlocks
- It is recommended to connect the inverter’s TA-TB (or OC1) relay contact to an external audible/visual alarm circuit or to an upper-level PLC for monitoring. This prevents undetected faults that could damage machinery or cause safety incidents.
- Circular looms often have mechanical interlocks or photoelectric sensors, which can also be connected to the inverter’s X terminals for quick stopping or emergency braking.
V. A More Intuitive “Central Control + Multiple Motors” Layout (Brief)
If a single circular loom has multiple motors that need coordination, you can use these approaches:
- Independent Inverters + Upper-Level PLC: Each motor has a VCD-2000 inverter, and the PLC gathers all sensors (speed, tension, switches, etc.) as well as HMI operations, then issues run commands/frequency references to each inverter via RS485 or digital signals.
- Master-Slave Mode: Set the main weaving motor’s inverter as the master, using the inverter’s built-in RS485 to send the speed or frequency to other slave inverters (function codes P4.21, P4.22, etc.). Ensure consistent inverter parameters and non-conflicting communication addresses.
VI. Common Precautions
- Confirm Motor Insulation: Especially for older motors or in harsh environments, measure insulation first to ensure it meets the inverter’s requirements.
- Low-Speed Cooling: If the loom will run for a long time at low speed with high torque, consider forced ventilation or a specially designed motor for inverters.
- Electromagnetic Interference (EMI): Strictly separate power cables from control signals or use shielded cables. If high accuracy is required for surrounding instruments, add line reactors or filters.
- Altitude Considerations: Above 1000 meters, you may need to derate the inverter or increase cooling.
- Ensure Adequate Safety Measures: Emergency stop and electrical interlocks should be paired with the inverter control terminals or external relays, tested thoroughly before production runs.
VII. Example Summary
In conclusion, for circular loom applications, the VCD-2000 series inverter can independently drive the main weaving motor and the winding/pulling motors. By configuring appropriate function codes and connecting external sensors/signals, you can implement multi-speed operation, PID tension control, fault-linked alarms, and more. The key steps are:
- Mechanical and Electrical Integration: Verify the power requirements of each shaft on the loom, select inverters with sufficient capacity, complete main circuit wiring, and ensure PE grounding.
- Control Terminal Planning: Assign X1–X6, FWD, and REV terminals for start/stop, forward/reverse, jog, multi-speed, PID enable, etc., according to the loom’s process needs.
- Parameter Settings: Perform motor auto-tuning in PA.00–PA.06, then adjust P0 (operation/frequency channel), P2 (accel/decel), P3/P8 (multi-speed/PLC), P4 (terminal definition), and P7 (PID) step by step based on on-site testing.
- Interlock Protection and EMI Suppression: Pay attention to low-speed heat dissipation, electromagnetic compatibility, fault relay outputs, and alarm circuits.
Following these practices, the circular loom can achieve excellent speed control performance, improve fabric quality and efficiency, reduce mechanical shock, and extend equipment lifespan. If later you need remote monitoring or more advanced automation, you can utilize the inverter’s built-in RS485 port to integrate with PLCs or HMIs. Please consult production requirements, safety standards, and the inverter manual for detailed on-site adjustments. Best wishes for a successful application!