Nord SK700E Series Frequency Inverters — SK700E-751-340-A

Technical Dossier

Product Details And Specifications

Nord SK700E Series: Comprehensive Module Range and Technical Overview

The Getriebebau NORD SK700E series is a vector-controlled frequency inverter platform engineered for demanding continuous-duty applications in the global heavy process industries. Installed across chemical plants, oil refineries, nuclear auxiliary systems, water treatment facilities, and offshore platforms, the SK700E occupies the mid-to-high power segment of NORD's drive portfolio, covering output ratings from 0.25 kW to 160 kW in three-phase 230 V, 400 V, and 480 V supply variants. Its modular I/O architecture, integrated PLC functionality (POSICON), and CANopen/PROFIBUS/PROFINET fieldbus compatibility make it a standard specification item in distributed control system (DCS) and SCADA environments where long service intervals and deterministic response times are mandatory. The SK700E-751-340-A specifically covers the 7.5 kW / 400 V / IP55 enclosed variant, a configuration widely deployed in pump and compressor drive applications requiring high ingress protection without an external enclosure.

The Evolution of SK700E Architecture

NORD introduced the SK700E as the successor to the SK700 series, retaining backward-compatible terminal layouts while integrating a 32-bit DSP control core in place of the earlier 16-bit architecture. Early SK700E units (pre-2008 production) used a discrete IGBT gate driver board (part reference BU0900) that required periodic capacitor replacement at 8-year intervals. From 2010 onward, NORD consolidated the gate driver and control board into a single PCB assembly, reducing component count and improving MTBF figures. The 2014 revision introduced onboard EMC Class C2 filters as standard on 400 V variants, eliminating the need for external line filters in most industrial cabinet installations. The SK700E-751-340-A belongs to the post-2014 production run and incorporates the integrated filter and the revised POSICON motion control firmware (v3.x). Compatibility with the earlier SK700 parameter sets is maintained via the ParameterBox SK PAR-3H, allowing direct parameter transfer during like-for-like replacements. As of 2024, the SK700E series has entered the mature/end-of-active-production phase; NORD continues to supply spare parts and repair services under its long-term maintenance program through 2034, making third-party spare parts sourcing a critical operational consideration for asset-intensive industries.

SK700E Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked models within the SK700E series, classified by power rating and supply voltage. All models share the core SK700E control architecture and are cross-compatible with NORD's fieldbus adapter and braking resistor accessories.

SK700E-250-340-A: 0.25 kW / 3-phase 400 V / IP55 / integrated EMC filter, standard I/O
SK700E-370-340-A: 0.37 kW / 3-phase 400 V / IP55 / suitable for light conveyor and fan loads
SK700E-550-340-A: 0.55 kW / 3-phase 400 V / IP55 / compact footprint for panel-mount applications
SK700E-750-340-A: 0.75 kW / 3-phase 400 V / IP55 / standard pump and agitator duty
SK700E-111-340-A: 1.1 kW / 3-phase 400 V / IP55 / integrated brake chopper
SK700E-151-340-A: 1.5 kW / 3-phase 400 V / IP55 / POSICON positioning control capable
SK700E-221-340-A: 2.2 kW / 3-phase 400 V / IP55 / CANopen fieldbus ready
SK700E-301-340-A: 3.0 kW / 3-phase 400 V / IP55 / PROFIBUS DP adapter compatible
SK700E-401-340-A: 4.0 kW / 3-phase 400 V / IP55 / extended I/O via SK TU4-PBR option
SK700E-551-340-A: 5.5 kW / 3-phase 400 V / IP55 / dual-ramp acceleration profile
SK700E-751-340-A: 7.5 kW / 3-phase 400 V / IP55 / high-torque vector mode, integrated EMC C2 filter — this listing
SK700E-112-340-A: 11 kW / 3-phase 400 V / IP55 / suitable for centrifugal pump duty cycles
SK700E-152-340-A: 15 kW / 3-phase 400 V / IP55 / PROFINET IRT adapter compatible
SK700E-222-340-A: 22 kW / 3-phase 400 V / IP55 / dynamic braking resistor terminal standard
SK700E-302-340-A: 30 kW / 3-phase 400 V / IP55 / compressor and blower duty, forced-air cooling
SK700E-452-340-A: 45 kW / 3-phase 400 V / IP55 / extended overload capacity 150% / 60 s
SK700E-552-340-A: 55 kW / 3-phase 400 V / IP55 / dual motor switching via internal contactor logic
SK700E-752-340-A: 75 kW / 3-phase 400 V / IP55 / heavy pump and fan, DC bus sharing capable
SK700E-113-340-A: 110 kW / 3-phase 400 V / IP55 / cabinet-mount, forced ventilation required
SK700E-163-340-A: 160 kW / 3-phase 400 V / IP55 / top-of-range, parallel DC bus configuration

Sourcing Hard-to-Find & Obsolete SK700E Parts

DriveKNMS maintains a dedicated inventory of SK700E units and associated sub-assemblies, including control boards, IGBT power modules, gate driver PCBs, and display/keypad units (SK PAR-3H). As the SK700E series transitions from active production to long-term maintenance support, the availability of factory-new units through standard distribution channels is declining. DriveKNMS sources stock through authorized surplus channels and direct OEM relationships, providing tested units with full traceability documentation. For end-users operating SK700E drives in critical process loops — particularly in refineries and chemical plants where drive replacement requires process shutdown — DriveKNMS offers advance exchange programs: a tested replacement unit is dispatched before the faulty unit is returned, minimizing downtime. Obsolete sub-assemblies including the BU0900 gate driver board and legacy 16-bit control cards for pre-2010 production units are held in dedicated long-term storage.

Quality Control for the SK700E Range

Each SK700E unit processed by DriveKNMS undergoes a structured test protocol before dispatch. Power stage verification is performed using a programmable AC source at rated input voltage (±10%) with resistive and inductive load banks simulating motor impedance. IGBT switching waveforms are captured on a four-channel oscilloscope to confirm gate timing symmetry and absence of shoot-through conditions. Control board functionality is validated by exercising all digital inputs, analog inputs (0–10 V and 4–20 mA), relay outputs, and the RS485/CANopen communication port against a reference PLC. For units with integrated EMC filters, common-mode leakage current is measured per EN 61800-3 Class C2 limits. Thermal imaging is applied during a 30-minute full-load run to identify hot spots on the heatsink, DC bus capacitors, and PCB power traces. Units that pass all stages are assigned a test report number and shipped with a 12-month warranty against manufacturing defects.