Finding the Best Current Switch for ECM Motors

Why are ECM Motors growing in popularity and what benefits they provide

Electronically commutated motors, or ECMs, are designed to operate at variable speeds, torques, or flows, using electronics and software to control their output. Unlike traditional binary motors that run at fixed speeds and simply turn on or off, ECM motors can adjust their output based on the load or input power, ensuring consistent output in various conditions. This makes them particularly suitable for HVAC applications, where maintaining a constant airflow through a building or space is crucial for ensuring good indoor air quality and occupant comfort. By keeping the air moving constantly, ECM motors also improve filtration and reduce the buildup of dust and particles in the air.

Why traditional current switches may not work well with ECM Motors.

Traditional current switches may not work well with ECM motors because they typically operate at very low currents in standby mode, and conventional current switches have relatively high trip points. Additionally, traditional current switches often require multiple wire wraps around the opening, which can add to the hysteresis or accuracy of the switch's electronics, making it impractical and ineffective in many situations. ECM motors require a current switch with a very low trip point, which can be adjustable and set above the standby current but below the current when the motor is turning, to ensure accurate readings of when the motor is running and turning but not in standby mode.

The ACI ECMCS25-A has addressed this issue by establishing a key differentiator with a low trip point of 0.075 amps, which stands as the industry's lowest for any split-core adjustable trip point current switch. The trip point turn potentiometer is designed to allow for fine tune adjustments. These combined, allow ECM motors to run s low as possible in terms of showing operational status. Additionally, this trip point can be adjusted to a value above the standby current but below the current when the ECM is in its lowest operating mode, ensuring that the motor's status is accurately determined when it is running and turning but not in standby mode.

Aside from the adjustable low trip point, this new ECM current switch also provides versatile mounting options. It can snap onto a 35 millimeter DIN rail using the removable bracket located at the bottom of the switch. Alternatively, it has a tab on the side that you can attach a wire tie to and secure it inside the motor housing, directly connected to the monitored wire.

The accessory device that indicates the on/off status of the switch is not integrated into the ECM current switch itself, but is a separate device. However, using this device is optional. You can also use a multimeter or your controller to monitor the status of the switch, and it is not necessary to have the accessory device in order to set up or adjust the new ECM current switch.