Product Overview
The Emerson SP4403 is a universal AC variable-frequency drive from the Unidrive SP series, originally developed by Control Techniques under the Emerson Industrial Automation brand and now part of the Nidec group. The SP4403 is a frame-size 4 drive rated for three-phase 380–480 V AC supplies, delivering 45 kW (60 HP) nominal output with 96 A continuous current. As a universal drive, the Emerson SP4403 is designed to control induction, permanent-magnet synchronous, and servo motors from a single hardware platform, with the control mode selected through parameter configuration rather than hardware changes.
The Unidrive SP4403 supports multiple control strategies, including open-loop and closed-loop rotor-flux vector control, servo (full-frequency-range vector) control, and V/Hz control. This flexibility allows the same drive to handle standard variable-speed fan and pump duties as well as high-dynamic positioning, winding, and synchronous applications. The drive provides 0–550 Hz output frequency, 150 % overload capability for 60 seconds, and supports incremental, SinCos, SSI, EnDat, and HIPERFACE encoder feedback types for closed-loop operation. An onboard dynamic braking transistor and DC injection braking are included, removing the need for several external components.
The Emerson SP4403 features an embedded programmable logic controller, configurable through SyPTLite ladder software, which can handle local interlocks and sequencing tasks and reduce the I/O burden on a connected PLC. Two expansion slots accept communication and I/O option modules, including Profibus DP, DeviceNet, Ethernet, extended I/O, and universal encoder interfaces. Commissioning is supported by CTSoft PC software, which provides parameter backup and restore, motor autotune, and drive diagnostics. Please note that the Unidrive SP range has been discontinued by the original manufacturer, so the SP4403 is now primarily available as surplus, refurbished, or replacement stock.
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | Emerson / Control Techniques Unidrive SP4403 |
| Manufacturer | Control Techniques (Nidec; formerly Emerson Industrial Automation) |
| Product Type | Universal AC Variable-Frequency Drive (VFD) |
| Product Series | Unidrive SP |
| Frame Size | 4 |
| Input Voltage | 380–480 V AC, 3-phase |
| Input Frequency | 48–65 Hz |
| Nominal Output Power | 45 kW (60 HP) |
| Continuous Output Current | 96 A |
| Overload Capacity | 150 % for 60 seconds |
| Maximum Output Frequency | 0–550 Hz |
| Control Modes | V/Hz, Open-loop vector, Rotor Flux Control (RFC), Closed-loop vector, Servo |
| Supported Motor Types | Induction (asynchronous), permanent-magnet synchronous, servo |
| Encoder Feedback | Incremental, SinCos, SSI, EnDat, HIPERFACE |
| Braking | Onboard dynamic braking transistor; DC injection braking |
| Built-in Functions | Embedded PLC logic (SyPTLite), onboard EMC filter |
| Communication | RS-485 / Modbus RTU standard; fieldbus via option modules |
| Expansion | Two option slots for communication and I/O modules |
| Enclosure Rating | IP20 |
| Mounting | Panel mount |
| Operating Temperature | 0 °C to +40 °C (derating above 40 °C) |
| Approximate Weight | 14.5 kg |
| Approximate Dimensions | 162 mm × 290 mm × 324 mm (W × H × D) |
| Certifications | CE, UL508 |
| Lifecycle Status | Discontinued / Obsolete — replacement spare |
