Electronically Commutated Motors (ECMs) are transforming HVAC and industrial systems thanks to their variable speeds, higher efficiency, and lower energy use. But with those benefits comes a challenge: accurately monitoring low and variable current draws. Standard current sensors often can’t keep up.
That’s where Functional Devices, a trusted leader in building automation components for over 50 years, comes in. Known for our RIB® (Relay-In-a-Box®) line, power supplies, sensors, and accessories, we’ve built our reputation on simplifying installation, boosting reliability, and helping customers meet modern energy and sustainability demands.
In this blog, we’ll cover why ECMs require specialized monitoring, how the RIBXGTA-ECM makes this easy, and the benefits it brings to efficiency, maintenance, and system performance.
Ready to simplify ECM monitoring? Explore the RIBXGTA-ECM or reach out to find the right solution for your system.
Understanding ECMs
Unlike traditional on/off motors, ECMs have built-in control boards that allow them to vary speed and respond to load conditions. This reduces energy consumption, extends motor life, and creates quieter, more flexible operation.
However, ECMs draw lower and fluctuating currents, which can make standard current sensors inaccurate. Without proper monitoring, small issues may go unnoticed, potentially leading to performance drops or equipment failure.
One distinction between 3-phase motors (or PSC motors) and ECMs is the fact that the ECM has a control board. Traditional motors are dumb, ECMs are smart. With a traditional 3-phase motor, it will reach full current draw for the application within seconds. That's the normal current draw. Any deviation from that current is a problem. When setting a current sensor, simply turn on the motor and adjust the trip point based on the current it is drawing.
ECMs, on the other hand, aren't just fully on or fully off. They can be programmed to slowly ramp up or ramp down the speed of the motor over the course of several minutes. They can operate at a specific CFM leading to unintuitive changes in current when there are changes in pressure in the HVAC system. There is also the standby current. The control board in the ECM always draws a bit of current which means the current sensor trip point can't just be set to zero.
Meet the RIBXGTA-ECM
The RIBXGTA-ECM is a current sensor specifically designed for ECM applications. Its adjustable low trip point (down to 0.25 amps) and LED indicators provide the sensitivity and ease of use needed for today’s energy-efficient motors.
Key benefits include:
- Adjustable trip point for low-current detection
- LED feedback for quick, accurate setup
- Reliable RIB quality for long-term performance
- Simple installation that saves time and labor
How It Works
If a standard 3-phase fan is blowing at any significant amount of CFM, the current drawn when the fan is on will reach many amps greater than when it is off. This gives a field operator setting an adjustable current sensor's trip point a lot of leeway. Just set it to two amps and call it a day.
ECMs draw much less current so that trip point needs to be a little bit more thoughtful. The RIBXGTA-ECM has LEDs on it which guide the operator, making setting a trip point of as small as 0.25 amps a breeze. Careful: be sure the current being set really is the intended operating point.
Setting up the RIBXGTA-ECM is straightforward:
- Run the ECM at its lowest normal speed.
- Attach the sensor to the current-carrying conductor.
- Use the LED indicator to set the correct trip point.
This ensures the sensor monitors true operating current rather than just the motor’s standby draw. Once installed, the RIBXGTA-ECM provides continuous monitoring, helping facility managers catch potential issues early, reduce downtime, and optimize system performance.
Use Cases and Applications
The RIBXGTA-ECM works wherever ECMs are used:
- Commercial HVAC systems
- Industrial equipment
- Predictive maintenance programs
By accurately monitoring ECMs, facility teams can make informed decisions, extend equipment life, and maintain smooth, efficient operation.
Track ECM Energy Usage with Confidence
Monitoring ECMs doesn’t have to be complicated. The RIBXGTA-ECM makes it simple to track low and variable current draws, reduce downtime, and maintain reliable system performance.
Take control of your ECM monitoring today. Explore the RIBXGTA-ECM and contact us with any questions.
About Functional Devices, Inc.
Confidence and Peace of Mind in Every Box
At Functional Devices, Inc., we have been designing and manufacturing high-quality electronic components in the USA since 1969. Our mission is simple: to enhance lives in buildings and beyond by delivering reliable, innovative solutions for the building automation industry. Our product lineup includes RIB® relays, current sensors, power controls, power supplies, transformers, lighting controls, and more—each designed to meet the highest industry standards.
We test 100% of our assembled products, ensuring an exceptionally low failure rate—less than 1 in 16,000 in the field. This commitment to excellence means you get products that perform reliably, reducing downtime and increasing efficiency. With every Functional Devices product, you receive more than just a component—you gain confidence and peace of mind knowing your systems are built on trusted, field-proven technology.