PXe-PI550 High Performance Current Vector Inverter

Motor Control

The PI550 converts the incoming AC supply to a controlled variable-voltage, variable-frequency output for the connected motor.

The drive can operate using sensorless vector control or V/F control, allowing the control method to be matched to the motor, mechanical load and required operating performance.

Sensorless Vector Control

Sensorless vector control provides improved speed and torque behaviour without requiring external encoder feedback.

Published performance includes:

• Speed range: 1:100
• Steady-speed accuracy: ≤0.5% of rated synchronous speed
• Torque response: ≤20ms
• G-type starting torque: 150% at 0.5Hz
• F-type starting torque: 100% at 0.5Hz

This mode is appropriate where improved low-speed torque and load response are required without the complexity of encoder feedback.

V/F Control

V/F control provides conventional voltage-to-frequency motor control for general variable-speed applications.

Available characteristics include linear, power-law and custom V/F curves together with automatic or manual torque boost.

V/F control is particularly suited to pumps, fans, conveyors and other standard industrial loads where full vector performance is not required.

Motor Self-Learning

The PI550 supports rotary and static motor-parameter identification, allowing motor characteristics to be established during commissioning.

Static identification can be useful where the motor cannot conveniently be rotated during commissioning, while rotary identification can provide more detailed motor parameter information where the installation permits it.

Hard Speed Tracking

Speed-tracking functionality allows the inverter to identify and track a motor that is already rotating before applying the controlled output.

This can be useful when restarting fans, pumps and other machinery where the motor may still be coasting following a stop or supply interruption.

Acceleration & Deceleration

Straight-line and S-curve acceleration and deceleration are supported.

Up to four acceleration/deceleration time settings are available, with a programmable range from 0.0 to 6500.0 seconds.

This allows starting and stopping behaviour to be matched to the mechanical load rather than applying an abrupt speed change.

G-Type & F-Type Duty

The PI550 includes G-type and F-type duty ratings on selected models.

G Type: 150% rated current for 1 minute and 180% for 2 seconds.

F Type: 120% rated current for 1 minute and 150% for 2 seconds.

Final inverter selection should consider motor current, starting torque and expected load duty rather than motor kW alone.

Built-In PID Control

Integrated PID control allows the PI550 to regulate a process variable using an external feedback signal.

Typical applications include pump pressure, flow, fan pressure, airflow and other closed-loop process-control duties.

PID feedback can use 0 to 10V DC or 0 to 20mA signals.

Multiple Speed Operation

Up to 16 preset speeds can be configured using multifunction terminals or programmed operating logic.

This is useful for machinery operating at several defined production or process speeds.

Frequency Reference

Available frequency-reference methods include:

• Digital setting
• Analogue voltage or current input
• Preset multi-speed settings
• Serial communication

The control source can therefore be selected according to whether the drive is operated locally, from an external control signal or through an automation system.

Command Sources

The PI550 can be controlled from:

• Local operating keypad
• Control terminals
• Serial communication

This allows the same drive platform to support standalone machinery or wider PLC-based systems.

Automatic Voltage Regulation

Automatic Voltage Regulation helps maintain the required motor output voltage as the incoming mains supply changes within the permitted input range.

Quick Current Limiting

The PI550 includes a current-limiting algorithm intended to reduce the likelihood of overcurrent trips during changing load conditions and short-duration increases in mechanical demand.

DC Braking

DC braking is available where additional motor stopping control is required.

Braking frequency, current and duration can be programmed according to the motor and mechanical load.

Applications involving rapid stopping, high-inertia loads or frequent braking cycles should be reviewed to determine whether an external braking resistor or other braking arrangement is required.

Common DC Bus

Multiple compatible drives can be configured around a common DC bus where required by the wider system design.

Common-bus installations should be engineered as a complete system, including rectification, protection, braking and regenerative-energy considerations.

Local Display & Fault History

The local keypad can display operating information including running frequency, set frequency, DC bus voltage, output voltage, output current, output power, output torque, motor speed, terminal status, analogue input, PID values and IGBT temperature.

The inverter can also retain information for up to three fault events, allowing operating conditions at the time of a fault to be reviewed.

Selecting a PXe-PI550 Current Vector Inverter

Correct inverter selection should consider the motor and driven equipment rather than motor power alone.

PX will normally review:

• Motor rated power, voltage, current, frequency and speed
• Available site supply and phase arrangement
• Type of driven machinery
• Required starting torque
• Acceleration and deceleration requirements
• Minimum and maximum operating speed
• Continuous and short-duration load duty
• G-type or F-type duty requirement
• V/F or sensorless vector control
• Analogue or digital control signals
• PID feedback requirements
• RS485 / Modbus RTU integration
• Braking requirements
• Ambient temperature and altitude
• Available control-panel space and ventilation

Input Supply Configurations

The PI550 is available in several supply-voltage families.

Single-Phase 220V Class
220 to 240V AC nominal, -15% / +10%, with selected models up to approximately 5.5kW.

Three-Phase 220V Class
220 to 240V AC nominal, -15% / +10%, with selected models up to approximately 11kW.

Three-Phase 380V Class
380 to 440V AC nominal, -15% / +10%, with selected models up to 22kW.

Three-Phase 480V Class
480V AC ±10%, with selected models up to 22kW.

Final model availability should be confirmed against the required voltage class, motor rating and load duty.

Single-Phase Motor Configurations

Selected G1S models are identified for single-phase motor loads.

Motor compatibility and the required output arrangement should be confirmed before selection, as this capability should not be assumed across the complete PI550 range.

RS485 / Modbus RTU

Built-in RS485 / Modbus RTU allows the PI550 to exchange operating commands, frequency references and status information with suitable PLC, HMI and automation systems.

The source wiring information specifies communication rates up to 115200bps.

Digital & Analogue I/O

The PI550 provides six programmable digital inputs, with DI5 capable of high-speed pulse input up to 100kHz.

One analogue input can be configured for:

• 0 to 10V
• 0 to 20mA

Available outputs include an open-collector output, programmable relay output and analogue output.

Emergency Stop / Output Interrupt Input

A programmable input can be used to interrupt the controller output as part of the machine control arrangement.

This input should not be assumed to provide a safety-rated emergency-stop function unless incorporated into a suitably designed and validated machine safety system.

Installation Environment

The standard PI550 is intended for indoor installation in an appropriately controlled electrical environment.

Published operating conditions include:

• Operating temperature: -10°C to 40°C
• Operation from 40°C to 50°C with derating
• Relative humidity below 90%, non-condensing
• No corrosive or explosive gases
• Protection from water, steam, conductive dust, oil mist and salt contamination
• No output derating below 1000m altitude
• 1% derating per additional 100m above 1000m
• Maximum published altitude: 3000m
• IP20 protection
• Forced-air cooling

Adequate ventilation and installation clearance should be provided around the inverter.

PXe-PI550 Technical Specification

Power Input

Motor Control

Overload Capability

I/O & Communications

Monitoring & Protection

Operating Environment

Specification note: Model availability, duty rating and final technical specification should be confirmed for the selected input voltage, motor rating and application.