Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | SP4403 |
| Manufacturer | Emerson / Control Techniques (now Nidec) |
| Product Series | Unidrive SP, Frame 4 |
| Product Type | Universal AC variable speed drive / VFD |
| Input Supply | 3-phase 380–480 VAC ±10%, 48–65 Hz |
| Continuous Output Current (Heavy Duty) | 96 A |
| Continuous Output Current (Normal Duty) | 104 A |
| Motor Rating (Heavy Duty) | ≈45 kW / 60 HP |
| Motor Rating (Normal Duty) | ≈55 kW / 75 HP |
| Overload Capability | 150% for 60 s |
| Output Frequency | 0–550 Hz |
| Control Modes | Open-loop V/f, open-loop vector, RFC, closed-loop vector, servo |
| Motor Types Supported | Induction, permanent-magnet synchronous, brushless servo |
| Switching Frequency | 3 / 4 / 6 / 8 / 12 / 16 kHz selectable |
| Option Slots | 2 (communication / I/O / encoder expansion) |
| Built-in Features | Dynamic brake transistor, DC injection braking, EMC filter, embedded logic |
| Protection Rating | IP20 |
| Operating Temperature | 0°C to +40°C (derating above 40°C) |
| Approximate Weight | ~14.5–30 kg (varies by source) |
| Certifications | CE, UL |
Main Features and Advantages
Single Hardware, Multiple Motor Technologies: The SP4403 eliminates the need to stock separate drives for induction, synchronous, and servo applications. Parameter selection determines whether the unit operates as a standard VFD, a permanent-magnet motor controller, or a servo amplifier. For facilities maintaining mixed motor populations on legacy Unidrive SP platforms, this consolidates spare parts inventory: one SP4403 can cover multiple drive scenarios across the plant .
Legacy Replacement Value: The SP4403 is no longer in active production, which makes verified, tested units strategically important for plants running Unidrive SP equipment. Because the mounting dimensions, terminal layout, and parameter files remain consistent with the original installation, a replacement SP4403 can be fitted without cabinet modification or system redesign. Parameter sets are portable through the SM-Keypad copy function or CTSoft software, enabling rapid restoration of drive configuration after a swap .
Integrated Braking and EMC Features: The SP4403 includes a built-in dynamic-brake transistor and DC-injection braking, removing the need for external chopper modules in many stop applications such as hoists or fans. The onboard EMC filter keeps conducted emissions within industrial limits without requiring a separate line filter in every cabinet, simplifying panel design and reducing component count .
Dual Duty Ratings for Application Flexibility: The carries two distinct rating tables. The heavy-duty rating of 96 A supports 150% overload for 60 seconds, suiting applications with high starting torque demands such as lifting, extruding, or winding. The normal-duty rating of 104 A serves steadier loads like fans and pumps, extracting approximately 10 kW more motor capacity from the same hardware. Selecting the correct rating table for the load profile is essential; using the normal-duty figure for a high-inrush application will result in overload trips .