Electric motors are the backbone of almost every industry, powering pumps, compressors, conveyors, fans, and many other machines. To run efficiently and safely, motors require proper protection. Selecting the correct breaker, overload relay, and starter type is essential to avoid failures, overheating, or costly downtime.
This is where our Motor Protection Calculator becomes useful.
Why Use a Motor Protection Calculator?
When sizing protection devices manually, engineers often rely on formulas and reference charts. While accurate, this process can be time-consuming. Our calculator automates these calculations, providing instant recommendations based on your motor’s load, voltage, efficiency, and power factor.
With this tool, you can quickly determine:
- Full Load Current (FLC) – the actual current your motor will draw at rated load.
- Overload Relay Range – the safe range to set thermal protection.
- Breaker Size – the correct miniature (MCB) or molded case (MCCB) circuit breaker to protect against short-circuits.
- Starter Type – whether your motor should use a Direct-On-Line (DOL) or a Star-Delta Starter.
- Contactor Ratings – for both main and auxiliary contactors in star-delta applications.
How It Works
You only need to enter:
- Load Value – in kW or HP
- Operating Voltage – default is 415 V, but you can adjust
- Power Factor – optional (default: 0.85)
- Efficiency – optional (default: 0.90)
After entering these values, click Calculate and the tool will instantly display the results.
Benefits of Using This Tool
- Saves time compared to manual calculations
- Improves accuracy using standard engineering methods
- Enhances safety by avoiding incorrect protection sizing
- Simple and accessible for engineers, electricians, and students
Important Note
This calculator provides general guidance based on standard assumptions. Always confirm results with:
- Manufacturer datasheets
- Local electrical codes and standards (IEC, IS, NEC, etc.)
- Professional electrical design practices
