🔍 Introduction
In modern industrial drive systems, especially those involving heavy loads and high inertia such as cable stranding machines (12, 18, 24, 30 bobbins), rewinders, unwinders, and winding/unwinding systems, controlling the stopping process is critically important.
It is not just about stopping — the system must stop accurately, at the right time, and at the correct position to ensure product quality.
This is where the braking resistor becomes an essential component.
⚡ What is a Braking Resistor?
A braking resistor is a device connected to an inverter (VFD), with the purpose of:
- Dissipating excess energy generated during motor deceleration
- Protecting the inverter from DC bus overvoltage
- Supporting fast and stable braking performance
🔥 Real Problems in Heavy Load, High Inertia Systems
Typical systems include:
- Multi-cage cable stranding machines
- Rewinders / unwinders
- Drive systems with large flywheels
Common characteristics:
👉 Large rotating mass
👉 Extremely high inertia
👉 Significant stored energy during operation
When stopping:
- This energy does not disappear
- It is fed back into the inverter
💥 What Happens WITHOUT a Braking Resistor?
When regenerative energy flows back to the inverter:
- DC bus voltage rises rapidly
- The inverter is forced to protect itself
Typical issues:
❌ Overvoltage (OV) faults
❌ Extended deceleration time
❌ Inaccurate stopping position
❌ Overshooting (overrun)
🎯 Why Is This Dangerous in Production Machines?
In machines like cable stranders or rewinders:
- Incorrect stopping timing → wrong pitch
- Position deviation → product defects
- Loss of synchronization → entire coil rejection
👉 The damage is not only technical
👉 It directly affects production cost and reputation
🚀 The Critical Role of a Braking Resistor
A braking resistor helps to:
✔ Absorb excess energy → converts regenerative energy into heat and dissipates it
✔ Stabilize DC bus voltage → keeps the inverter operating within a safe range
✔ Enable fast deceleration → not limited by overvoltage conditions
✔ Ensure precise stopping → allows the inverter to follow the configured deceleration ramp
🧠 Key Technical Insight
👉 For light loads:
A braking resistor may not be required
👉 For heavy loads with high inertia:
Without a braking resistor
➡️ The inverter loses control over the stopping process
In other words:
No braking resistor = No precise stopping
👉 How to Size a Braking Resistor
Refer to the following guide: https://parkervietnam.com/en/hoi-dap/braking-resistor-calculation-and-reference-table-for-parker-ac10-drives/
⏱️ Practical Comparison
| Criteria | With Braking Resistor | Without Braking Resistor |
|---|---|---|
| Stopping time | Fast, as configured | Extended |
| Accuracy | High | Inaccurate |
| Stability | Stable | Unpredictable |
| System faults | Minimal | Frequent OV faults |
🏭 Practical Applications
Braking resistors are especially important in:
- Multi-cage cable stranding machines (12–30 bobbins)
- Packaging industry machines (rewind, slitting)
- Heavy lifting systems
- Steel rolling mills, wire drawing machines
📌 Conclusion
A braking resistor is not just an accessory for an inverter.
👉 It is a critical factor that determines:
- Braking performance
- Stopping accuracy
- Final product quality
Especially in heavy load and high inertia systems:
“Without a braking resistor, the system can still run — but the stopping process cannot be controlled.”
📞 Contact for Consultation & Solutions
We specialize in:
- Selecting the right braking resistor for your load
- Designing braking systems for high inertia machines
- Upgrading inverter systems with genuine Parker products
👉 Contact us now for on-site technical support!
📞 Hotline: +84 908 353 714 (Mr. Lam)
📧 Email: info@kythuatviet.vn
