⚙️ ONE INVERTER – MULTIPLE MOTORS: IS IT A GOOD IDEA?
Many engineers often ask: “Can one inverter control multiple motors at the same time?”
The answer is yes – but it must follow strict technical principles to ensure both safety and efficiency.
1️⃣ When Can One Inverter Be Used for Multiple Motors?
This setup is only recommended when:
- All motors are of the same type, power rating, and similar speed range.
- All motors start and stop simultaneously.
- Individual speed control for each motor is not required.
🔧 Typical examples: Ventilation systems, parallel pumps, twin conveyors, or dual feeders.
2️⃣ Mandatory Technical Considerations
✅ The inverter’s power must be at least equal to the total rated power of all motors plus an extra 20% safety margin (depending on inertia load).
⚠️ Avoid relying on the inverter’s built-in motor protection for individual motors – it only monitors total current and cannot detect single motor faults.
➡️ Each motor must have its own protection device (CB, MCCB, thermal relay, etc.).
⛔ Do not reverse the direction of individual motors when sharing a single inverter.
⛔ Do not use vector control or encoder feedback mode when driving multiple motors.
3️⃣ How to Wire One Inverter for Multiple Motors
- Connect the inverter output → branch power lines to each motor.
- Individual contactors can be used to start/stop each motor if necessary.
- Ensure the total output current does not exceed the inverter’s rated capacity.
4️⃣ How to Select the Proper Inverter Power Rating
Example: 3 motors, each 2.2kW and 5.4A → Total 6.6kW / 16.2A
- Equivalent inverter: 7.5kW / 17A
- With safety margin: 6.6kW × 1.2 = 7.92kW
- ✅ Recommended inverter: 11kW or higher to ensure overload protection.
Figure: Parker AC20 inverter controlling 3 motors in a parallel system
🔚 Conclusion
Using one inverter to control multiple motors is a cost-saving solution, but it should only be applied when:
- All motors operate synchronously.
- No individual speed adjustment is required.
- System is carefully calculated for current capacity, protection, and control method.
💡 Need help configuring an inverter to control multiple motors, or selecting the right model for your application?
Contact Kỹ Thuật Việt (Parker Drives Vietnam) – our experienced engineering team is ready to assist with the most efficient and reliable drive solutions.
