ABB ACS550 General Purpose AC Drive 0.75 to 355 kW
Overview
The ABB ACS550 is a general purpose AC drive for three-phase induction motors from 0.75 kW up to 355 kW. ABB built the range to be simple to buy, install, configure and use, with common user and process interfaces, common fieldbus options, common software tools for sizing and commissioning, and common spare parts across the series. Typical duties are pumps, fans and constant torque loads such as conveyors, where a standard drive is needed and no special product engineering is required.
ABB now lists the ACS550 among its legacy low-voltage drives, yet a very large installed base remains in service across Oman and the wider GCC in water pumping stations, building services, process plants and utilities. Seven Star LLC supplies ABB ACS550 drives and related options to maintenance teams and contractors in Muscat, Sohar, Duqm and Salalah, with engineering support in Muscat to help match a replacement unit to the existing type designation, frame size and option codes on site.
Operating Principle
The ABB ACS550 rectifies the three-phase mains supply into a DC link and then uses an IGBT inverter to synthesise a variable-voltage, variable-frequency output from 0 to the supply voltage and 0 to 500 Hz. By controlling output frequency the drive sets motor speed, and by controlling the voltage-to-frequency relationship and current vector it controls motor torque. The ACS550 uses vector control, giving open-loop speed accuracy of 20% of motor nominal slip and, with encoder feedback, closed-loop accuracy of 0.1% of nominal speed. Torque step rise time is under 10 ms with nominal torque in both open and closed loop.
On the line side of the ABB ACS550, ABB fitted a patented swinging choke that matches inductance to the actual load. ABB states that this reduces total harmonic distortion emissions by up to 25%, which matters on weak supplies or generator-fed networks common at remote oil and gas sites. Combined with the built-in category C2 EMC filter as standard, many installations need no additional external filtering. The practical consequence is lower energy use on variable-torque loads, soft starting with no current surge on the motor, and reduced mechanical stress on pumps, belts and couplings.
Engineering Design of the ABB ACS550
The ABB ACS550 is produced as wall-mounted ACS550-01 units in frames R1 to R6 and free-standing ACS550-02 units in frame R8. Wall-mounted drives are available in IP21 (UL Type 1) and, with option +B055, IP54 (UL Type 12) up to 160 kW. Frame R1 measures 369 mm high with the cable connection box, 125 mm wide and 212 mm deep at 6.5 kg in IP21, while frame R6 reaches 888 mm in height and 69 kg. Circuit boards are coated for harsh environments, the cooling fan runs only when needed, and switching frequency can be raised automatically when the drive is cool to reduce motor noise.
The type designation identifies each unit, for example ACS550-01-08A8-4: series, construction (01 wall-mounted or 02 free-standing), current rating, and voltage range (4 for 380 to 480 V, 2 for 208 to 240 V). A brake chopper is built in up to 11 kW. The standard control board offers two analog inputs, two analog outputs, six digital inputs, three relay outputs, a 24 V DC auxiliary supply and EIA-485 with Modbus. The assistant control panel provides two soft-keys, a help button, a real-time clock for time-stamped fault tracing and a changed-parameters menu, and it can copy parameters between drives.
Key Features
The ABB ACS550 combines the following functions in one general purpose drive platform:
- Power range from 0.75 to 355 kW at 380 to 480 V and 0.75 to 75 kW at 208 to 240 V, with automatic identification of the input line.
- Vector control that improves motor control performance and opens up a wider range of applications than simple scalar drives.
- A patented swinging choke that reduces total harmonic distortion emissions by up to 25% according to ABB.
- Category C2 (first environment) and C3 (second environment) RFI filtering as standard, avoiding extra external filters in many panels.
- Energy efficiency counters showing saved kWh, CO2 and cost in local currency, plus a load analyser that stores current and torque history.
- Commissioning assistants for start-up, PID control, serial communication and drive optimisation, and a maintenance assistant that tracks energy, running hours or motor revolutions.
- Built-in Modbus on EIA-485 and plug-in fieldbus adapters including PROFIBUS DP (RPBA-01), DeviceNet (RDNA-01), CANopen (RCAN-01) and EtherNet/IP (RETA-01).
- FlashDrop interface for fast parameter setting without mains power, and DriveWindow Light software for PC-based start-up and monitoring.
Industrial Applications
In Oman, the ABB ACS550 is most often found driving centrifugal pumps in water transmission and supply stations, booster sets in residential and hospital complexes, cooling tower and air handling fans in district cooling plants, and conveyors in cement, aggregate and food plants. The ABB ACS550 normal-use rating suits variable-torque pump and fan loads with 10% overload for one minute in ten, while the heavy-duty rating allows 50% overload for one minute in ten for conveyors, mixers and positive displacement pumps.
Because many ABB ACS550 units have been running for years in the Sohar and Salalah industrial zones, the typical requirement today is a like-for-like replacement that matches the existing frame, cabling and fieldbus card so that downtime is minimal. Seven Star LLC supplies ACS550 drives, control panels and plug-in options as a trusted supplier to plant engineers in the GCC, and can also advise when a project is better served by the current ABB ACS580 general purpose drive. For smaller machinery loads we also supply the compact ABB ACS355-03E-08A8-4 machinery drive and the ABB ACS350 11 kW inverter drive.
Technical Specifications
The table summarises the main ABB ACS550 data from the ABB ACS550 catalog; confirm the exact rating from the type designation on the existing nameplate.
| Parameter | Specification |
|---|---|
| Model | ABB ACS550 general purpose drive (ACS550-01 wall-mounted, ACS550-02 free-standing) |
| Supply voltage and power | 3-phase 380 to 480 V +10/-15%, 0.75 to 355 kW; 3-phase 208 to 240 V +10/-15%, 0.75 to 75 kW |
| Supply frequency / power factor | 48 to 63 Hz / 0.98 |
| Output | 3-phase, 0 to Usupply, 0 to 500 Hz |
| Overload | Normal use 1.1 × I2N for 1 min every 10 min; heavy-duty 1.5 × I2hd for 1 min every 10 min; 1.8 × I2hd for 2 s every 60 s |
| Switching frequency | Default 4 kHz; selectable 1, 2, 4, 8, 12 kHz |
| Acceleration / deceleration | 0.1 to 1800 s |
| Analog inputs / outputs | 2 × 0(2) to 10 V or 0(4) to 20 mA / 2 × 0(4) to 20 mA |
| Digital inputs / relay outputs | 6 × 12 to 24 V DC (PNP or NPN) / 3 relays, 250 V AC or 30 V DC |
| Communication | EIA-485 Modbus built in; optional PROFIBUS DP, DeviceNet, CANopen, EtherNet/IP and other plug-in adapters |
| Degree of protection | IP21 standard; IP54 (option +B055) up to 160 kW |
| Ambient temperature | -15 to 50 °C, no frost; derating from 40 to 50 °C |
| Altitude | Rated current to 1000 m; 1% derating per 100 m from 1000 to 4000 m |
| Frames and weights | R1 to R6 wall-mounted (6.5 to 69 kg in IP21); R8 free-standing |
| Approvals | UL, cUL, CE, C-Tick, GOST R; RoHS compliant |
How to Order
To source an ABB ACS550 drive, send Seven Star LLC a formal RFQ with the full type designation from the nameplate (for example ACS550-01-031A-4 with any +option codes), the motor rating and the installation details. Our instrumentation and automation team in Muscat will check availability and lead time, confirm compatibility with your existing panel, control panel and fieldbus adapter, and provide the ABB ACS550 catalog for download with the quotation. Seven Star LLC supplies ABB drives to industrial customers throughout Oman and the GCC with engineering support in Muscat.
- Catalog ABB ACS550 Catalog (3AFE64792857) Download

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