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The Emerson SP4403 is an AC drive in the Unidrive SP series, used to regulate motor speed and torque in industrial machinery. It is suited to applications that require substantial motor output and adjustable operation under changing process loads. Typical installations include heavy-duty conveyors, extrusion lines, winding equipment and industrial process machinery where motor speed must follow production requirements.
The SP4403 operates from a three-phase 380–480 V AC supply. Its rated output is 55 kW in Normal Duty operation and 45 kW in Heavy Duty operation, with continuous output-current ratings of 104 A and 96 A respectively. These ratings are important when matching the drive to a motor that operates under varying torque demands, frequent acceleration or sustained production loads.
The drive supports several motor-control strategies, including V/Hz and vector-based operation, as well as compatible feedback-based configurations. Built-in RS-485 communication, configurable control I/O, onboard PLC functionality and expansion options allow the SP4403 to exchange commands and status information with an automation system. The final configuration depends on the motor, feedback requirements and the control functions needed by the machine.
| Parameter | Specification |
|---|---|
| Manufacturer | Emerson / Control Techniques |
| Model | SP4403 |
| Product Series | Unidrive SP |
| Product Type | AC Variable Frequency & Servo Drive |
| Drive Configuration | Panel-Mount AC Drive |
| Input Voltage | 380–480 V AC |
| Input Phase | Three-phase |
| Input Frequency | 48–65 Hz |
| Normal Duty Output Power | 55 kW |
| Heavy Duty Output Power | 45 kW |
| Normal Duty Output Current | 104 A |
| Heavy Duty Output Current | 96 A |
| Control Modes | V/Hz, open-loop vector, rotor flux control and supported closed-loop control modes |
| Built-in Communication | RS-485 |
| Serial Communication Protocol | Modbus RTU |
| Control Interfaces | Configurable analog and digital I/O |
| Expansion Capability | Compatible option modules |
| Programmable Logic | Onboard drive PLC functionality |
| Parameter Storage | Smartcard support |
| Enclosure Protection | IP20 |
| Cooling Method | Forced-air cooling |
| Dimensions | 510 × 298 × 310 mm |
| Weight | 4 kg |
The SP4403 converts incoming three-phase AC power into a controlled output for the connected motor. By adjusting output voltage and frequency according to the selected control strategy, it regulates motor operation in response to speed references, load conditions and configured limits.
In a heavy-duty conveyor installation, the machine controller can send a speed reference to the SP4403 as production demand changes. The drive adjusts the motor output according to the configured acceleration and deceleration ramps, helping coordinate material movement with upstream and downstream equipment. The required current rating must account for the motor load and the duty classification selected for the application.
Open-loop control can be used where encoder feedback is not required. For applications needing feedback-based speed or torque regulation, compatible feedback hardware and the appropriate drive configuration are necessary. The onboard PLC can handle supported local logic, while serial communication and optional modules support integration with the wider control system.
During commissioning, motor nameplate data, control mode, duty rating, current limits and ramp settings must be matched to the actual operating conditions. This is particularly important where the machine experiences high starting torque or repeated changes in load.
The SP4403 serves as the motor-regulation stage between the electrical supply and the driven machine. It receives commands from a PLC or another configured control source, regulates the electrical output to the motor and makes available operating information for the automation system.
Three-Phase AC Supply → SP4403 AC Drive → AC Motor → Industrial Machinery
| System Component | Function | Relationship to the SP4403 |
|---|---|---|
| SP4403 AC Drive | Regulates motor speed and torque | Controls the electrical output supplied to the motor |
| Three-Phase AC Supply | Supplies electrical power | Feeds the drive input |
| AC Motor | Converts electrical energy into mechanical motion | Drives the connected machinery |
| PLC or Machine Controller | Executes machine sequencing and interlocks | Sends commands and speed references |
| Encoder or Feedback Device | Measures speed or position where required | Supports compatible closed-loop configurations |
| RS-485 Communication Interface | Exchanges serial data | Connects the drive to compatible control equipment |
| Analog Reference Source | Supplies a configured speed or process reference | Provides an input for motor regulation |
| Digital Control Signals | Carry enable, run, stop and status signals | Support external control and monitoring |
| Braking Resistor | Dissipates braking energy where required | Supports applications with demanding deceleration requirements |
| Communication Option Module | Adds supported network connectivity | Extends the available communication interfaces |
| Feedback or I/O Option Module | Adds compatible feedback or signal-handling functions | Adapts the drive to application requirements |
| Electrical Protection Devices | Provide electrical protection and isolation | Form part of the surrounding motor installation |
| Application | Typical Equipment | Role of the SP4403 |
|---|---|---|
| Heavy-Duty Conveyors | Bulk-material and production-transfer conveyors | Regulates motor speed under changing transport loads |
| Extrusion Machinery | Industrial plastic and material-processing lines | Controls motor operation during continuous production |
| Winding Equipment | Industrial web handling and winding systems | Supports speed regulation and compatible feedback control |
| Pumping Systems | High-capacity process and utility pumps | Adjusts motor speed according to process demand |
| Industrial Fans | Large ventilation and process-air equipment | Regulates airflow through variable-speed operation |
| Packaging Machinery | High-throughput packaging and transfer systems | Coordinates motor operation with production sequences |
| Printing Machinery | Industrial printing and web-handling equipment | Regulates motor speed during production |
| Material Handling | Industrial transfer and movement equipment | Controls motor operation according to the required movement profile |
| Processing Machinery | Industrial cutting and material-processing systems | Regulates motor speed under varying process loads |
| General Manufacturing | Machines using higher-current AC motors | Provides adjustable motor control for production equipment |
| Component | Function | Relationship to the SP4403 |
|---|---|---|
| Unidrive SP Keypad | Provides local parameter access and operating-status information | Supports local setup and monitoring when fitted |
| Smartcard | Stores compatible parameters and programs | Supports configuration backup and transfer |
| Encoder Feedback Module | Interfaces with compatible motor feedback devices | Enables supported closed-loop configurations |
| Communication Option Module | Adds supported industrial network interfaces | Connects the drive to compatible automation systems |
| I/O Option Module | Adds compatible input and output functions | Extends signal-handling capabilities |
| Braking Resistor | Dissipates braking energy where required | Supports demanding deceleration applications |
| AC Motor | Converts electrical power into mechanical motion | Serves as the controlled load |
| PLC | Coordinates machine logic and interlocks | Sends commands and receives drive-status information |
| Electrical Isolation Device | Provides isolation for servicing | Supports safe maintenance procedures |
| Motor Protection Devices | Provide protection for the motor circuit | Complement the wider electrical installation |
| Model / Product | Product Type | Relationship | Selection Consideration |
|---|---|---|---|
| Emerson SP4403 | Unidrive SP AC Drive | Main product | Match the 380–480 V supply and required duty rating |
| Emerson SP4402 | Unidrive SP AC Drive | Related model in the same frame family | Compare output-current requirements and motor load |
| Emerson SP4401 | Unidrive SP AC Drive | Related model in the same frame family | Evaluate whether its output rating meets the application requirements |
| Emerson SP5401 | Unidrive SP AC Drive | Higher-frame model in the same series | Consider when the required motor current exceeds the SP4403 rating |
| Unidrive SP Feedback Option Modules | Drive Feedback Modules | Related configuration components | Select according to the required encoder or feedback interface |
| Unidrive SP Communication Option Modules | Drive Communication Modules | Related configuration components | Match the required industrial network and protocol |
| Unidrive SP Braking Components | Drive Braking Accessories | Related application components | Evaluate the load’s braking and stopping requirements |
The SP4403 is rated at 55 kW and 104 A in Normal Duty operation, and 45 kW and 96 A in Heavy Duty operation. Selection should account for the motor’s rated current, load profile and required overload performance.
The Unidrive SP platform supports V/Hz and vector-based control, along with compatible closed-loop configurations. The appropriate mode depends on the motor type, feedback hardware and required speed or torque response.
Yes. The built-in RS-485 interface supports serial communication with compatible control equipment. Configurable I/O and compatible communication option modules can support additional integration requirements.
Check the motor data, duty classification, current limits, control mode, speed references and ramp settings. Applications with high starting torque or frequent load changes also require careful verification of the drive’s operating limits and machine response.