Nord SK700E-751-340-A Replacement for SK 700E Series

Product Overview

Nord SK700E-751-340-A Replacement for SK 700E Series: Smooth Transition & Legacy System Compatibility

Upgrading or replacing a discontinued or aging Nord SK700E-751-340-A variable frequency drive does not have to mean extended downtime or costly system redesigns. The Nord SK700E-751-340-A is a 75kW, 340A three-phase AC variable frequency drive from Nord Drivesystems’ proven SK 700E series — a platform widely deployed in conveyor systems, pump stations, compressor lines, and heavy industrial machinery across manufacturing, water treatment, and process automation environments. This replacement and upgrade solution is engineered to deliver a seamless migration path from legacy SK 700E installations, preserving your existing wiring topology, control architecture, and communication infrastructure wherever possible.

Whether your facility is retiring an end-of-life SK700E-751-340-A, responding to an unplanned drive failure, or proactively modernizing a control cabinet as part of a broader PLC or DCS migration, this unit provides a direct-fit solution. The SK 700E series maintains consistent terminal layouts across the power range, meaning that in most retrofit scenarios, existing motor cables, control wiring, and braking resistor connections can be reused without modification. The drive’s integrated EMC filter and built-in brake chopper further reduce the need for external components during the changeover.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful SK700E-751-340-A retrofit rarely involves the drive alone. In practice, the migration process touches multiple components within the same control cabinet or automation system. When replacing this 75kW drive, engineers commonly evaluate the condition and compatibility of the SK TU3-PBR PROFIBUS option module — if the existing card is functional, it can be transferred directly to the replacement unit, preserving the PROFIBUS DP node address and network configuration without reprogramming the upstream PLC or DCS.

For installations where the host controller is a Siemens S7-300 or S7-400 PLC communicating over PROFIBUS DP, the drive replacement is transparent to the controller provided the GSD file and station address remain unchanged. Similarly, sites running a Siemens S7-1500 or Allen-Bradley ControlLogix with a PROFIBUS master card will find the SK700E-751-340-A replacement fully compatible at the network layer. In Modbus RTU environments — common in older SCADA-linked pump or fan control systems — the SK TU3-MBR module retains its register map, so no changes to the host PLC program or HMI tag database are required.

Beyond the drive itself, the retrofit scope often includes inspection or replacement of the SK PAR-3H parameter box used for on-site parameter cloning, the 24VDC control power supply feeding the drive’s logic board, and any signal isolators or terminal blocks on the I/O wiring. In cabinet installations where multiple SK 700E drives share a common DC bus or a shared braking resistor bank, the SK700E-751-340-A’s built-in brake chopper ensures compatibility with the existing resistor sizing. Engineers should also verify the condition of the motor encoder feedback cable if the application uses closed-loop vector control via the SK TU3-INC incremental encoder option card.

For sites migrating from an older Nord SK 500E or SK 300E series drive to the SK 700E platform, the terminal mapping differences are well-documented in Nord’s migration application notes. The SK700E-751-340-A supports all standard Nord motor protection functions including PTC thermistor input, electronic motor overload, and phase-loss detection — features that may not have been present on earlier-generation drives being retired. In multi-drive systems, the replacement integrates cleanly alongside existing SK 700E units of other power ratings, such as the SK700E-550-340-A (55kW) or SK700E-900-340-A (90kW), without requiring changes to the shared control architecture or cabinet bus bar arrangement.

Retrofit Guidance FAQ

Q: Can I reuse the existing motor and control wiring?
A: Yes. The SK700E-751-340-A uses the same terminal layout as all SK 700E series drives in this frame size. Motor output terminals (U, V, W), mains input terminals (L1, L2, L3), PE, and the standard control terminal strip are pin-compatible. No rewiring is required in the vast majority of direct replacement scenarios.

Q: Will my existing PLC program need to be modified?
A: No, provided the fieldbus option card (e.g., SK TU3-PBR for PROFIBUS or SK TU3-MBR for Modbus RTU) is transferred from the old unit and the station address is preserved. The drive’s parameter set can be cloned using the SK PAR-3H parameter box or NORDCON software, so the PLC sees an identical device on the network.

Q: Is the physical footprint identical for cabinet installation?
A: Yes. The SK700E-751-340-A occupies the same frame size H mounting footprint as the original unit. Existing DIN rail or panel mounting holes, cable entry points, and cooling airflow clearances are unchanged. No cabinet modification or new cutouts are required.

Q: Which communication protocols are supported?
A: The SK700E-751-340-A supports PROFIBUS DP (via SK TU3-PBR), CANopen (via SK TU3-CAO), Modbus RTU (via SK TU3-MBR), and DeviceNet (via SK TU3-DNO) through plug-in option modules. The base unit also supports analog (0–10V, 4–20mA) and digital I/O control without any option card.

Q: Can parameters from the failed drive be recovered and loaded into the replacement?
A: If the original drive’s parameter box (SK PAR-3H) was used for backup, parameters can be loaded directly into the replacement unit on-site without a laptop or NORDCON software. If no backup exists, TOPNLMS can provide a factory default parameter set matched to your motor nameplate data upon request.

Q: What if my application uses closed-loop vector control with an encoder?
A: The SK TU3-INC incremental encoder option card is compatible with the replacement unit. The existing encoder cable and feedback wiring can be reused. Verify encoder supply voltage (5V or 24V) and pulse count settings match the original configuration before commissioning.

Warranty Assurance

Every Nord SK700E-751-340-A unit supplied by TOPNLMS is covered by a 12-month warranty from the date of shipment. Prior to dispatch, each unit undergoes a pre-shipment functional inspection including power-on verification, output voltage balance check, and control terminal continuity test. Units are packed in anti-static foam with original or equivalent protective packaging to prevent transit damage.

In the event of a warranty claim, TOPNLMS provides a replacement-first policy: a verified defective unit will be replaced or credited without requiring the customer to wait for repair turnaround. Our after-sales response target is within 24 hours of claim submission. Warranty coverage includes manufacturing defects and functional failures under normal operating conditions; it does not cover damage resulting from incorrect installation, overvoltage events, or environmental exposure beyond the drive’s rated IP class.

For procurement teams requiring documentation, TOPNLMS can provide a test report, packing list, and commercial invoice with HS code declaration for customs clearance. Stock is held in Xiamen and ships via DHL Express, FedEx International Priority, or sea freight depending on order volume and urgency. Lead time for in-stock units is typically 3–5 business days to most destinations.

For technical pre-sales support, compatibility verification, or bulk pricing inquiries, contact our team directly.