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The Emerson SP3403 is a high-power AC drive in the Unidrive SP series, used to regulate motor speed and torque in industrial machinery. It is suited to production equipment where motor output must respond to changing loads, adjustable speed references or coordinated machine sequences. Typical applications include extrusion lines, material-handling systems, winding equipment and process machinery driven by three-phase AC motors.
The SP3403 operates from a three-phase 380–480 V AC supply. Its published power ratings are 30 kW for Normal Duty and 22 kW for Heavy Duty, with corresponding continuous output-current ratings of 56 A and 46 A. These ratings are relevant when selecting a drive for a machine that experiences frequent starts, changing torque demand or sustained operation under load.
The drive supports different motor-control methods and can exchange commands and status information with an automation controller. Built-in serial communication, configurable control I/O, an onboard drive PLC and expansion slots allow the SP3403 to fit into a range of machine-control arrangements. The required configuration depends on the motor, feedback equipment, communication needs and operating profile.
| Parameter | Specification |
|---|---|
| Manufacturer | Emerson / Control Techniques |
| Model | SP3403 |
| 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 | 30 kW |
| Heavy Duty Output Power | 22 kW |
| Normal Duty Output Current | 56 A |
| Heavy Duty Output Current | 46 A |
| Peak Output Current | Up to 80.5 A under specified operating conditions |
| Control Modes | Open-loop V/Hz, open-loop vector 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 Slots | Compatible option-module slots |
| Programmable Logic | Onboard drive PLC functionality |
| Parameter Storage | Smartcard support |
| Enclosure Protection | IP20 |
| Cooling Method | Forced-air cooling |
| Dimensions | 368 × 250 × 260 mm |
| Weight | 3.5 kg |
The SP3403 converts incoming three-phase AC power into a controlled electrical output for the connected motor. Its output voltage and frequency change according to the selected control mode, motor parameters and requested operating conditions.
Consider an extrusion line where motor speed affects material throughput. The machine controller sends a speed reference to the SP3403, which regulates the motor according to the configured operating profile. Acceleration and deceleration settings determine how quickly the motor responds to changes in production demand, while drive status signals help the controller coordinate other equipment.
For applications that do not require encoder feedback, open-loop control can regulate motor operation without a feedback device. Where the application needs closed-loop performance, a compatible feedback arrangement and the appropriate drive configuration are required. The onboard PLC can handle supported local drive logic, while serial communication and option modules extend integration with the wider control system.
Commissioning requires the motor data, duty classification, control method, reference signals and operating limits to be matched to the actual load. The drive’s current and power ratings must also be suitable for the motor and its operating conditions.
The SP3403 forms the motor-regulation stage between the electrical supply and the machine’s mechanical load. A PLC or other configured control source supplies operating commands and references, while the drive adjusts motor output and returns available status information.
Three-Phase AC Supply → SP3403 AC Drive → AC Motor → Industrial Machinery
| System Component | Function | Relationship to the SP3403 |
|---|---|---|
| SP3403 AC Drive | Regulates motor speed and torque | Controls the electrical output delivered 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 |
The actual architecture depends on the selected control mode, motor type, feedback requirements, communication network and machine safety arrangement.
| Application | Typical Equipment | Role of the SP3403 |
|---|---|---|
| Conveyor Systems | Production conveyors and transfer lines | Adjusts motor speed to coordinate material movement |
| Extrusion Machinery | Plastic extrusion and material-processing lines | Regulates motor speed during continuous production |
| Winding Equipment | Web handling and winding machines | Supports speed regulation and compatible feedback control |
| Pumping Systems | Industrial process and utility pumps | Adjusts motor speed according to process demand |
| Industrial Fans | Ventilation and process-air equipment | Regulates airflow through variable-speed operation |
| Packaging Machinery | Automated packaging and conveying systems | Coordinates motor operation with production sequences |
| Printing Machinery | Printing presses 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 |
| Cutting and Processing Machinery | Industrial cutting and processing equipment | Regulates motor speed during machine cycles |
| General Manufacturing | Machines with variable-speed AC motors | Provides adjustable motor control for production operations |
| Component | Function | Relationship to the SP3403 |
|---|---|---|
| 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 SP3403 | Unidrive SP AC Drive | Main product | Match the 380–480 V supply and required duty rating |
| Emerson SP3402 | Unidrive SP AC Drive | Related model in the same frame family | Compare output-current requirements and load characteristics |
| Emerson SP3401 | Unidrive SP AC Drive | Related model in the same frame family | Evaluate motor power and overload requirements |
| Emerson SP2403 | Unidrive SP AC Drive | Related drive in a smaller frame family | Consider only if its electrical ratings meet the application requirements |
| 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 |
Related models and accessories are not automatically interchangeable. Selection depends on electrical ratings, motor characteristics, control mode, feedback requirements and the installed option configuration.
The SP3403 has a Normal Duty rating of 30 kW and 56 A, and a Heavy Duty rating of 22 kW and 46 A. Selection should account for motor current, load characteristics and the application’s overload requirements.
Yes. Open-loop control modes do not require encoder feedback. Closed-loop operation requires a compatible feedback device and the appropriate drive configuration.
An option module may be required when the application needs a particular communication network, additional I/O or a supported motor-feedback interface that is not covered by the installed configuration.
Verify the motor data, duty classification, control mode, speed references, ramp settings, feedback configuration and external interlocks. Test motor direction, speed response, stopping behavior and fault handling before normal production begins.