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Brand: Flender
Flender N-EUPEX Pin Coupling
Description
A flexible pin coupling for pump, fan and gearbox input shafts
The Flender N-EUPEX pin coupling connects machine shafts through elastomer flexibles and compensates shaft misalignment with low restoring forces. In Flender’s catalog FLE 10.2 (edition 2026.1) the N-EUPEX is the overload-holding, fail-safe series; its sibling N-EUPEX DS is the overload-shedding series, where an overloaded flexible is destroyed so that the metal parts turn freely without contact.
The catalog gives typical uses as pump drives, ventilator drives and crane running gear, frequently connecting a motor to a gear unit input shaft, and as an add-on coupling on FLUDEX fluid couplings or ARPEX AKR safety couplings. It is suited to drives with uniform to average dynamic loads. The couplings follow a modular principle: types are made up of sub-assemblies, and wear is limited to the elastomer flexibles, which are replaced at the end of their service life.
Technical specifications
| Parameter | Specification |
|---|---|
| Series | N-EUPEX (fail-safe) and N-EUPEX DS (non-fail-safe), catalog FLE 10.2 Edition 2026.1 |
| Sizes and rated torque | 23 sizes, rated torque 28 Nm to 71,000 Nm for the standard series (catalog introduction: 12 Nm to 93,500 Nm across the family including soft and HP flexibles) |
| Ambient temperature | -50 to +80 C standard; -60 to +100 C with alternative flexibles |
| Standard types | A, B, D, E, DK, DKS, H, P, O, DBDR, ABD, ERN; DS types ADS, BDS, HDS |
| Flexible materials | NBR 80 Shore A (black with blue stripe), NBR 65 Shore A soft, HP TPU 97 Shore A, HP NBR 90 Shore A, electrically insulating NBR (green), NR low temperature, HNBR high temperature |
| Parts material | Cast iron with lamellar or spheroidal graphite, or steel; aluminium sleeve pipes on type DK spacers |
| ATEX marking | II 2G Ex h IIC T6 … T4 Gb X; II 2D Ex h IIIC T85 C … 110 C Db X; I M2 Ex h Mb X |
| Document | Flender catalog FLE 10.2, Edition 2026.1 (excerpt: introduction and N-EUPEX chapter) |
Types and variants
Type A is the fail-safe three-part design, which allows the flexibles to be changed without moving the machines because the bolted cam ring can be released. Type B is the two-part variant, where a machine must be moved to change the flexibles. Types D and E are flange variants, DK and DKS are double-cardanic with a spacer for large misalignment, H uses an adapter, P and O carry brake drums, ABD and DBDR carry brake disks, and ERN adds a slip unit. Special types on request include taper clamping bush hubs, intermediate shafts and SAE J620d flange dimensions.
Selecting a size
Rated and maximum torque depend on the flexible hardness (65, 80 Shore A or HP), and the catalog tables relate each size to IEC standard motors. State the driven machine, power and speed, shaft diameters and keyways, the required spacer or brake element, ambient temperature and whether the coupling will be used in an explosive atmosphere. For a gearbox pairing see the published Flender ONE gear unit; couplings are grouped in Electric Motors.
Documents and quotation
The Flender document is attached. Seven Star LLC supplies Flender couplings on request and quotes against the exact type, size and bore. The attached PDF is an excerpt of the manufacturer’s catalog FLE 10.2 (the full file exceeds the hosting limit): cover, introduction and N-EUPEX chapter, pages unaltered. Confirm bore sizes, flexible type and any ATEX requirement before ordering.
Datasheets & Documents
- Datasheet Flender catalog FLE 10.2 Edition 2026.1 (EXCERPT: introduction and N-EUPEX chapter) Download
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About brand
Large industrial gearboxes are the product most engineers associate with Flender, a company founded in 1899 and based in Bocholt, Germany, that builds gear units, couplings and drive systems. Seven Star LLC sources and supplies Flender gear units and their spare parts for mills, conveyors, pumps and marine drives in Oman, working from the nameplate data. On some nameplates the name appears as Siemens Flender.
Flender gearbox types listed here
Four items are listed. Flender ONE is the manufacturer's redesigned single-stage helical gear unit. The H2SV 09 is a two-stage helical gear unit of size 09 with a solid output shaft, shown here with a cooling coil and oil tank. The NAVILUS line covers marine gearboxes, listed in a multiple-input, single-output arrangement that brings several engines onto one propeller shaft, and in a version for dredgers. Flender couplings such as the flexible N-EUPEX type are often ordered with a gear unit.
Ordering a Flender gearbox or parts: what we need
Send a photo of the nameplate showing type, size, serial or order number, ratio, power and speeds. For spares, the serial number lets the parts list be traced, so add the item number of the bearing, seal or gear set you need. For a new unit, give the driven machine, motor power and speed, output speed, mounting position, shaft arrangement, ambient temperature and cooling method. Marine and dredger gearboxes for GCC yards also need the class society.
Browse Flender products by category: Electromotors, Electric Motors & Pumps.
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Frequently Asked Questions
How many sizes does the N-EUPEX have?
23 sizes with rated torque between 28 Nm and 71,000 Nm for the standard series, per the catalog chapter.
What is the difference between N-EUPEX and N-EUPEX DS?
N-EUPEX is overload-holding and fail-safe; N-EUPEX DS sheds overload by destroying the flexible, after which the metal parts rotate without contact.
What temperature range applies?
-50 to +80 C, extendable to -60 to +100 C with alternative flexibles.
Is it available for explosive atmospheres?
Yes, the catalog gives ATEX marking II 2G Ex h IIC T6 to T4 Gb X and II 2D Ex h IIIC T85 to 110 C Db X.
Can the flexibles be changed in place?
On the three-part types the bolted cam ring can be released so that the flexible can be changed without moving the machines; on two-part types a machine must be moved.
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