The ACH550 is an variable frequency AC drive designed specifically by ABB for the HVAC market that achieves the ultimate in flexible motor control performance. Offering two modes of motor control: Scalar (V/Hz) and Sensorless Vector, the ACH550 provides accurate speed control for any standard squirrel cage motor.

With drives ranging from 0.75 to 160kW, the ACH550 series features an intuitively multi-lingual, graphic display panel that also provides an assistant to aid users in start-up. The control panel can be mounted on the cover of the drive, or remotely, and can upload, store, and download parameters.

The ACH550 comes equipped with an extensive library of pre-programmed HVAC application macros that, at the touch of a button, allow rapid configuration of inputs, outputs, and parameters for specific HVAC applications to maximize convenience and minimize start-up time.

The ACH550 can be used for the simplest to the most demanding HVAC applications. Two internal option slots can be configured with additional relay outputs as well as a host of different communication bus adapters.

AHU fan speed control

The AHU fan speed is typically controlled to regulate the static pressure in the air duct. The ACH550 process PID controller compares the desired pressure (the setpoint) with the actual pressure (the feedback) from a pressure sensor and adjusts the fan speed to maintain the pressure at the desired level. The Setpoint is typically entered using the Operator Control Panel or a serial communications command.

Damper control

 • Drive started output

The Drive Started output indicates that the drive has received a Start command and the drive is not prevented from starting by a fault trip or an open Start Enable (safety) input. The Drive Started relay output serves as the command to open a damper such as an outdoor air damper, fire damper, isolation damper, etc.

• Run enable input

The Run Enable input operates as a permissive run input. Once the Drive Started status is achieved, closing the Run Enable input allows the motor to run. When the damper is fully open, a normally open dry contact (damper end-switch) closes and provides the Run Enable command and allows the motor to operate.

• Stop sequence

When the drive is commanded to stop during the normal course of operation or through the operation of a safety interlock or fault trip, the motor stops and the damper is commanded to close.

Dedicated exhaust fan function (smoke purge)

This is an input that causes the drive to ignore keypad and serial communication commands and run at an adjustable preset speed or operate in PID mode. Certain fault conditions are also ignored. This input would typically be used for purging smoke or pressurizing an area.

Night setback input

An input or a serial communications command changes drive settings for night or weekend operation.

Chilled water valve PID Loop

The ACH550 External PID Controller can be used to control a valve to regulate the flow of chilled water to maintain the chilled water coils at a set temperature.

Hot water valve control

The hot water valve can be connected to an ACH550 relay or analogue output terminal for control by the Building Management System using the ACH550 Pass-Through I/O capability.

Building Management System (BMS)

The Building Management System can monitor and control all aspects of the ACH550 through serial communication ports or the building network.

More on ACH550 for building automation

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