Description
WH5 Light-Industrial Cast-Iron Oldham Coupling — Medium-Speed Pump, Blower and Packaging Drives
The WH5 light-industrial Oldham coupling addresses the broad medium-speed light-industrial drive population. With 280 N·m rated torque, 25–32 mm bore range, 5.8 kg mass, and 4 700 rpm permissible speed, the WH5 covers centrifugal pump main drives, industrial root blower outputs, packaging-machine principal shafts, and the mid-sized irrigation-pump drives that anchor agricultural water-management systems across global emerging markets. The 280 N·m rating corresponds closely to the shaft output of the 2.2–4 kW motor class — one of the single largest installed-base populations in global light-industrial equipment.
For pump applications specifically, the WH5 delivers an important reliability advantage over rigid-shaft couplings. Centrifugal pumps depend on impeller-shaft bearing life for pump reliability, and bearing life is acutely sensitive to radial shaft loads. A rigid coupling transmits motor-shaft misalignment directly into the pump bearing as a radial load; the WH5’s 0.5 mm parallel-misalignment tolerance absorbs this misalignment as friction work at the slider interface rather than as radial load on the pump bearing. Field experience across multiple pump OEM and end-user deployments consistently shows extended bearing life and reduced shaft-seal leakage rates when a WH5 cross-slider coupling is substituted for a rigid-flange or jaw-coupler specification at this size class.
Specifications
| Parameter | Value |
|---|---|
| Model | WH5 |
| Nominal Torque (Tn) | 280 N·m |
| Permissible Speed (n) | 4 700 rpm |
| Bore Range (d) | 25 – 32 mm |
| Mass | 5.8 kg |
| Radial Misalignment (Δy) | 0.5 mm |
| Angular Misalignment (Δα) | 0.5° |
| Axial Misalignment (Δx) | 0.6 mm |
| Hub Material | HT200 grey cast iron |
| Slider Material | Hardened carbon steel |
| Lubrication | Grease (annual) |
| Shaft Engagement | Keyway + setscrew |
Materials
HT200 Cast Iron Hubs
Precision-machined HT200 grey cast-iron hubs with stress-relief annealing. At 5.8 kg total coupling mass, each hub contributes approximately 2.7 kg — manageable without hoist support for single-technician field maintenance. Cast-iron surface naturally develops a protective oxide layer, providing inherent corrosion resistance in mild-ambient installations without external coating.
Hardened Steel Slider
Induction-hardened carbon steel cross-slider providing near-zero-backlash transmission with grease-lubricated sliding. At the WH5’s 280 N·m and 4 700 rpm operating envelope, the steel-on-cast-iron sliding interface maintains consistent friction characteristics across the full operating cycle, producing predictable slider wear-rate and facilitating maintenance scheduling.
Keyway + Setscrew Mounting
Standard H7-reamed bore with parallel keyway to GB/T 1096 and M10 set-screw. For pump applications with frequent shaft removal (e.g., annual impeller inspection), a clamp-collar adapter can be fitted over the standard keyway bore without hub modification. This preserves the WH5’s standard-stocked specification while adding the convenience of clamp-mount removal.
Pump Bearing Life and Misalignment
Centrifugal pump bearing life follows the L10 fatigue model, where bearing life varies as the inverse cube of the radial load. Even modest misalignment — 0.1–0.2 mm of parallel offset at the coupling — translates into a meaningful radial force on the pump bearing when transmitted through a rigid coupling. At 0.2 mm of offset and a typical pump-shaft stiffness, a rigid coupling imposes approximately 150–250 N of additional radial bearing load. Applied to a typical pump bearing with a 4 500 N rated dynamic capacity, this reduces L10 bearing life by 10–25 %. Over a five-year pump service life, this translates into one to two additional bearing-replacement events per pump — each requiring the pump to be removed from the circuit, bearings replaced, and seal checked.
The WH5 eliminates this mechanism entirely. The 0.5 mm parallel-misalignment tolerance absorbs the realistic motor-to-pump frame tolerance without imposing any radial load on the pump bearing. Field reports from WH5 retrofit installations consistently document extended bearing life and reduced shaft-seal replacement frequency — tangible operational savings that justify the modest price premium over rigid couplings. For pump OEM designers, specifying the WH5 reduces warranty-claim exposure in the pump-bearing and shaft-seal categories that historically dominate pump warranty data. For further selection guidance, see Ever-power’s pump-application coupling guide.
Industry Applications
Centrifugal Pump Main Drives
Motor-to-pump coupling on 2.2–4 kW centrifugal pumps for water supply, irrigation, HVAC circulation, and process-fluid transfer. Misalignment tolerance extends pump bearing and shaft-seal life.
Industrial Root-Blower Outputs
Reduction-output to blower-rotor drive couplings on Roots-type blowers for conveying, aeration, and pneumatic-conveying systems. Near-zero-backlash supports consistent blower-pressure delivery.
Packaging-Machine Principal
Principal-shaft drives on flow-wrap packaging machines, form-fill-seal equipment, and stretch-wrapper main drives. Annual maintenance aligns with packaging-line planned-maintenance schedules.
Agricultural Irrigation Pumps
Motor-to-pump coupling on centre-pivot and drip-irrigation pump sets in large-scale commercial agriculture. Durability in seasonal outdoor-operation ambient across multi-year irrigation-season cycles.
Light Process-Industry Pumps
Small chemical-process, pharmaceutical-process, and cosmetics-manufacturing pump drives. Cast-iron hub compatible with mild-process-chemical ambient when fitted with appropriate coupling guard.
Retrofit Pump Couplings
Drop-in replacement for rigid-flange couplings, jaw-coupler specifications, and worn spider-type designs on legacy pump installations. Bore range covers dominant pump-shaft sizes in the 2.2–4 kW class.
Why Choose Ever-power
Quality & Compliance
WH5 production runs under ISO 9001:2015. Documentation covers RoHS, REACH, and CE conformity. For pump OEM customers, supplementary bearing-life extension documentation and misalignment-benefit analysis are available to support sales and warranty documentation. For agricultural and irrigation customers, outdoor-ambient durability documentation is supplied on request.
Retrofit Economics
The WH5’s value proposition in retrofit applications is clear: lower acquisition cost than precision-coupling alternatives, longer service life than spider-coupling alternatives, and demonstrable bearing-life extension that reduces pump maintenance cost. Hub-only and slider-only supply options support partial-replacement retrofit economies.
Aftermarket
WH5 sliders and hubs stocked for 2-business-day shipment. 5.8 kg mass is courier-shipment standard; express-courier available for emergency replacements. English-speaking engineering desk responds within 24 hours. Distributor volume-pricing and stock programmes supported.
Customer Reviews & Case Studies
★★★★★
Sierra Leone — Water-Treatment Utility
Used in: Motor-to-pump coupling on centrifugal pumps at a municipal water-treatment and distribution station.
Feedback: “Previous specification was rigid flanged coupling — pump bearing failures were averaging 14 months. Retrofit to WH5 across 12 pump sets has now delivered 4 years without a single bearing-related downtime event. The maintenance team initially questioned the cost of switching from rigid couplings, but the bearing-replacement savings paid back the coupling cost within the first year. Strongly recommended for any pump station retrofit.”
★★★★★
Liberia — Large-Scale Rice-Farm Irrigation
Used in: Motor-to-pump coupling on centre-pivot irrigation pump sets across a 2 000-hectare commercial rice farm.
Feedback: “Irrigation season runs 8 months per year with minimal maintenance access during peak operation. WH5 specification has delivered 5 irrigation seasons without coupling-related stoppages. Annual maintenance during the dry season is a 20-minute grease-repack task per pump set. Outstanding reliability for remote agricultural operation.”
★★★★☆
Guinea — Pharmaceutical Light-Mixing Facility
Used in: Motor-to-mixer coupling on pharmaceutical mixing-vessel drives at a regional pharmaceutical-manufacturing facility.
Feedback: “GMP environment with regular batch-changeover cleaning cycles. The WH5 has handled 3 years of three-shift duty across 8 mixer drives without coupling-attributable downtime. Knock one star only because the initial documentation pack for our GMP validation required supplementary material-compatibility statements that took 3 weeks to obtain — we would appreciate this documentation being part of the standard pharma-market pack.”
Frequently Asked Questions
How much bearing life extension does the WH5 provide over rigid couplings?
Under typical installation conditions (0.1–0.3 mm parallel offset between motor and pump shaft centres), substituting a WH5 for a rigid flange coupling removes a radial bearing load component of approximately 100–400 N per bearing. Using the L10 bearing-life formula (life varies as inverse cube of load), this translates to 20–60 % extended bearing L10 life. Actual field results vary by pump type, bearing specification, and operating conditions, but consistent bearing-life improvement is the documented outcome across WH5 pump-retrofit installations.
Can the WH5 be used on vertical-shaft pump installations?
Yes. For vertical-shaft centrifugal pump installations (common in borehole, deep-well, and submersible-discharge configurations), the WH5 operates identically in both horizontal and vertical shaft orientations. The only modification required is a sealed coupling guard to prevent lubricant migration under gravity in vertical installations — specify the coupling guard as a separate item when ordering for vertical-shaft pump duty.
What alignment procedure is recommended for maximum bearing-life benefit?
For maximum bearing-life benefit, align motor and pump shafts to within 0.2 mm parallel offset and 0.1° angular before coupling installation — achievable with dial-gauge alignment without laser tools. The WH5’s misalignment envelope will then absorb the residual tolerance and any subsequent thermal-growth drift without imposing radial loads on the bearings. Do not rely on the coupling misalignment tolerance to substitute for adequate initial alignment.
Is the WH5 appropriate for outdoor agricultural pump installations?
Yes. For seasonal outdoor agricultural pump duty (irrigation seasons of 6–9 months with off-season storage), specify a calcium-sulfonate complex grease for corrosion protection during off-season storage, and install a UV-resistant coupling guard to protect the cast-iron hub surfaces from direct sunlight and precipitation. Annual re-greasing at the start of each irrigation season maintains optimum slider-interface condition across multi-year seasonal cycles.
What is the recommended commissioning alignment check?
After WH5 installation and before first start-up: (1) verify set-screw torque (M10 set-screw to 18 N·m); (2) rotate the coupled assembly by hand through two full revolutions to verify smooth operation and absence of binding; (3) confirm coupling-guard clearance around both hubs. After the first 50 operating hours, re-check set-screw torque — initial seating of hub on shaft keyway may produce slight settling, requiring a re-tightening pass to maintain positive axial retention.
Quote WH5 for Pump and Blower Applications
For centrifugal pump, root-blower, packaging-machine, irrigation pump, and process-industry light-pump applications in the 280 N·m mid-speed class, the WH5 delivers measurable bearing-life extension and operational reliability improvements over rigid-coupling specifications. Browse the wider WH series catalogue, read about Ever-power’s pump-coupling capability, or enquire directly below.