AERCO Belimo GMX24-MFT Actuator - Manual (Page 8)

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Operation
Electrical Features
Electrical Operation
General
Belimo non-spring return actuators utilize Halomo sensorless Brushless DC motor
technology developed by Belimo. The non-spring return actuators use this motor in
conjunction with an Application Specific Integrated Circuit (ASIC). The Halomo ASIC
provides the intelligence to provide a constant rotation rate to prevent damage to
the actuator.
Initialization
When a power source is applied the motor carries out an initialization of the
actuator. The purpose of this initialization is to determine the mechanical angle of
rotation and to adapt the running time to the angle of rotation. When power is
applied, the internal microprocessor recognizes that the actuator is at its full-safe
position and uses this position as the base for all of its calculations.
Brushless DC Motor Operation
Belimo’s Halomo sensorless brushless DC motor spins by reversing the poles of
stationary electromagnets housed inside rotation permanent magnets. The
electromagnetic poles are switched by a special ASIC developed by Belimo. Unlike
the conventional DC motor, there are no brushes to wear or commutators to foul.
Motor Position Detection
Belimo's Halomo motor technology is a sensorless, brushless DC motor. The
Halomo technology eliminates the need for potentiometers for positioning. The
Halomo ASIC detects the spinning rotor by monitoring the back EMF of the motor
poles. The ASIC counts these pulses and calculates position within 1/3 of a motor
revolution.
Overload Protection
The Belimo non-spring return actuators are electronically protected from overload at
all angles of rotation by digital technology in the ASIC. The ASIC circuitry constantly
monitors the rotation of the brushless DC motor inside the actuator and stops the
pulsing to the motor when it senses an overload. The motor remains energized and
produces full rated torque when in overload.
The overload filtration helps increase the actuators installed life expectancy by
filtering out unnecessary control signal changes or end-stop pulsing while in
overload. This helps ensure that dampers are fully closed and that edge and blade
seals are always properly compressed.
Control Accuracy and Stability
All Belimo actuators have built-in
brushless DC motors which provide
better accuracy and longer service life.
Belimo non-spring return actuators are designed with a unique non-
symmetrical deadband. The actuator follows an increasing or decreasing
control signal with a 75 mV resolution. If the signal changes in the opposite
direction, the actuator will not respond until the control signal changes by
175 mV. This allows these actuators to track even the slightest deviation very
accurately, yet allowing the actuator to “wait” for a much larger change in
control signal due to control signal instability.
Satisfied
Control Position
Minimum
Control Resolution
75 mV
Actuator responds to a 75 mV signal when
not changing direction from stop position.
Satisfied
Control Position
Minimum Reversed
Control Deadband
Prior to Normal Control
175 mV
Actuator responds to a 175 mV signal when
reversing direction from stop position.