IDMT Calculator
Calculate the tripping time for an IDMT relay based on fault current.
Calculation Result
Tripping Time (t):
About the IDMT Calculator
This tool helps you calculate the tripping time of an Inverse Definite Minimum Time (IDMT) relay. These relays are crucial in electrical power systems for protecting equipment from overcurrents caused by faults.
The tripping time of an IDMT relay is inversely proportional to the fault current; the higher the current, the faster the relay operates. This calculator uses the standard formula to provide a precise tripping time based on your inputs. It's an essential tool for electrical engineering students and professionals.
What is an IDMT Relay?
An Inverse Definite Minimum Time (IDMT) relay is a type of protective relay used in electrical systems to protect circuits from overcurrent conditions.
The word “Inverse” means that the higher the fault current, the faster the relay operates, while “Definite Minimum Time” refers to the minimum time the relay will take to trip, regardless of how high the fault current is.
In simple terms:
- Small fault → longer tripping time
- Large fault → shorter tripping time
This type of relay ensures both sensitivity and selectivity in power system protection.
Why Use an IDMT Calculator?
Calculating the tripping time of an IDMT relay manually can be time-consuming and error-prone, especially when dealing with complex formulas and curve constants.
That’s where the TrueAiCalculator’s IDMT Calculator helps. It allows you to instantly calculate the tripping time based on the fault current, relay pickup current, time dial setting (TDS), and curve type — all in a user-friendly interface.
How to use the TrueAiCalculator IDMT tool
- Enter Fault Current (Ifault) — input measured or calculated fault current in Amperes.
- Enter Relay Pickup Current (Ipickup) — the relay setting, typically a multiple of the rated current.
- Enter Time Dial Setting (TDS) — a multiplier to increase/decrease operating time.
- Select IDMT Curve Type — pick standard, very inverse, or extremely inverse.
- Click Calculate — get the tripping time immediately.
Benefits of Using Our Online IDMT Calculator
Accurate & Reliable: Based on industry-standard IDMT equations.
Fast Calculation: Get instant results without manual effort.
User-Friendly Design: Simple and clean interface for easy input.
Supports Multiple Curves: Choose the right curve for your system.
Accessible Anywhere: Works on mobile, tablet, and desktop browsers.
Conclusion
The IDMT Calculator by TrueAiCalculator.com makes it effortless to compute relay tripping times accurately. Whether you’re a power system engineer, an electrical student, or a protection specialist, this free online tool saves time and enhances reliability in your calculations.
Frequently Asked Questions
Common questions about IDMT relays.
An IDMT relay is a type of electrical relay whose operating time is inversely proportional to the magnitude of the fault current. It operates faster for higher currents and slower for lower currents.
The different curves (Standard, Very, Extremely) represent different levels of inverse characteristics. Each curve has specific constants (A, p) in the IDMT formula that define its behavior.