Description
WH4 Light-Industrial Cast-Iron Oldham Coupling — Mid-Speed Fan, Mixer and Textile-Machine Drives
The WH4 light-industrial Oldham coupling moves the WH family into the territory of genuine mid-speed working drives. With 160 N·m rated torque, 20–28 mm bore range, 2.5 kg mass, and 5 700 rpm permissible speed, the WH4 covers a broad mid-range of light-industrial drive applications — industrial fan main drives, mid-sized process-mixer outputs, textile-machine main shafts, small-scale conveyor-head drives, and the principal-rotation drives of food-processing and pharmaceutical light-mixing equipment. The 160 N·m rating is a particularly useful engineering specification, corresponding closely to the shaft-output of the 1.5–2.2 kW motor class that anchors a large population of light-industrial drive trains globally.
The WH family’s architectural positioning relative to the SL series is worth understanding for engineers encountering the WH4 in the context of an existing SL-series specification. The WH4 is a lighter, higher-speed, lower-torque alternative to the SL family members in the same outer-diameter range. At 70 mm hub OD (approximately the same as SL70 family), the WH4’s 160 N·m and 5 700 rpm envelope contrasts with the SL70’s 125 N·m at 250 rpm — the WH family trades torque for speed, targeting mid-speed equipment classes rather than the slow-speed heavy process drives that SL family was optimised for. This trade-off makes WH4 the preferred choice for industrial fans (3 000–5 000 rpm class), mixer outputs (500–2 000 rpm class), and textile-machine drives (1 000–3 000 rpm class) where the SL series would be an over-specified heavy-weight solution.
Specifications
| Parameter | Value |
|---|---|
| Model | WH4 |
| Nominal Torque (Tn) | 160 N·m |
| Permissible Speed (n) | 5 700 rpm |
| Bore Range (d) | 20 – 28 mm |
| Outside Diameter (D) | ~70 mm |
| Mass | 2.5 kg |
| Radial Misalignment (Δy) | 0.4 mm |
| Angular Misalignment (Δα) | 0.5° |
| Axial Misalignment (Δx) | 0.5 mm |
| Hub Material | HT200 grey cast iron |
| Slider Material | Hardened carbon steel |
| Backlash | Near-zero (small running clearance) |
| Lubrication | Grease (annual) |
| Shaft Engagement | Keyway + setscrew |
Materials
HT200 Grey Cast Iron Hubs
Hubs are precision-machined from HT200 grey cast iron with stress-relief annealing before final bore machining. The HT200 specification provides adequate mechanical properties for the WH4’s 160 N·m torque and 5 700 rpm speed profile while delivering the cost-economic position that makes the WH family the preferred choice in retrofit and budget-sensitive applications. Hub mass is approximately 1.1 kg each — 30–40 % lighter than equivalent SL-family members at similar OD, meaningfully reducing system inertia.
Hardened Carbon Steel Slider
Cross-slider is hardened carbon steel with induction-treated sliding faces. The steel slider interfaces with the cast-iron hub slots to produce the cross-slider’s characteristic near-zero-backlash transmission. Grease lubrication at annual intervals maintains the steel-on-cast-iron interface in optimum condition, with slider service life typically spanning 5–8 years under standard light-industrial duty.
Standard Keyway Mounting
H7-reamed bore with parallel keyway to GB/T 1096 standard. M8 set-screw for axial location. Standard keyway mounting is appropriate at the WH4’s 160 N·m and 5 700 rpm — the shock-load profile is benign compared to the SL series, and the keyway-shear mechanism is well inside its endurance envelope. For applications requiring frequent hub removal, clamp-collar adapters can be fitted over the standard keyway bore without modification.
Mid-Speed Industrial-Fan Engineering
Industrial centrifugal fans — used in HVAC, process ventilation, baghouse dust-collection, and furnace-atmosphere control — form one of the largest single application populations for the WH4. Fan drives operate in the 1 450–4 800 rpm range (50 Hz direct-on-line or VFD-controlled), typically through a V-belt reducer, with misalignment accumulating from the motor-flange and fan-shaft bearing-housing tolerance stack-up. The WH4’s 0.4 mm radial misalignment envelope comfortably absorbs this tolerance stack without imposing radial loads on the fan bearing or motor bearing, extending bearing life meaningfully compared to a rigid-coupling specification.
For retrofit applications — replacing aged couplings on existing industrial fan installations — the WH4’s practical advantages are particularly clear. The cast-iron hub bore range (20–28 mm) covers the dominant motor-output shaft sizes in the 1.5–2.2 kW fan class. The near-zero-backlash transmission introduces no torsional oscillation into the belt drive. The annual grease-maintenance schedule aligns with typical fan-maintenance cycles. And the 2.5 kg mass is a practical field-handling specification — a single maintenance technician can perform WH4 hub replacement without hoist support. See the complete WH series range for related specifications.
Industry Applications
Industrial Centrifugal Fans
HVAC, process-ventilation, baghouse, and furnace-atmosphere centrifugal fan main drives in the 1.5–2.2 kW motor class. Misalignment tolerance preserves fan and motor bearing life across annual operating cycles.
Mid-Sized Process Mixers
Reduction-output to impeller-shaft drives on 500–1 000 L industrial mixers for paint, adhesive, polymer, and chemical-process applications. Torque rating comfortable for the 1.5–2.2 kW impeller-drive class.
Textile-Machine Main Shafts
Main-shaft drives on weaving machines, warping machines, and textile-finishing equipment. High rpm compatibility and light mass minimise textile-machine vibration content from the drive train.
Small Conveyor Head Drives
Head-pulley drive couplings on light-duty package-conveying, food-processing, and pharmaceutical-manufacturing conveyors. Annual grease maintenance aligns with production-line planned-maintenance schedules.
Pharma Light-Mixing
Principal-rotation drives on pharmaceutical light-mixing vessels and tablet-coating-pan drives. Cast-iron hub material is compatible with GMP hygienic-zone environments when fitted with appropriate coupling guard.
Retrofit Legacy Equipment
Direct-replacement specification for aged GBC, Falk-flexible, and generic-spider couplings on legacy mid-speed industrial equipment. Bore range and OD compatibility supports drop-in replacement without shaft modification.
Why Choose Ever-power
Quality & Compliance
WH4 production runs under ISO 9001:2015. Documentation covers RoHS, REACH, and CE conformity. The WH series is specifically designed for cost-competitive retrofit and light-industrial OEM markets — full compliance documentation is standard without premium cost. For pharma-adjacent customers, supplementary cast-iron material compatibility statements are available.
Value Proposition
The WH4 delivers the fundamental cross-slider Oldham coupling advantages — near-zero backlash, misalignment tolerance, constant-velocity transmission — at an economic price point appropriate for light-industrial OEM and retrofit applications. Hub-only supply is supported for customers retaining the existing slider across a bore-only upgrade. Slider-only supply is also stocked for maintenance replacements without full coupling swap.
Aftermarket
WH4 sliders and hubs stocked for 2-business-day shipment. 2.5 kg mass supports standard courier shipment. English-speaking engineering desk responds within 24 hours. For distributors, volume-pricing frameworks and stock-and-ship programmes are routinely supported.
Customer Reviews & Case Studies
★★★★★
Tonga — Industrial HVAC Contractor
Used in: Fan main-drive coupling retrofit on commercial HVAC air-handling units across a multi-building hotel complex.
Feedback: “Original elastomer-spider couplings had been averaging 18-month replacement cycles in the salt-air coastal environment. The WH4 cast-iron specification has now passed 4 years without a single coupling-related callout. Maintenance crew can handle the annual grease repack during regular HVAC service visits without specialist support. Excellent cost-effective retrofit specification.”
★★★★★
Solomon Islands — Textile Processing Facility
Used in: Main-shaft drive coupling on weaving-machine frames on a light textile-manufacturing floor.
Feedback: “High-humidity tropical ambient had been hard on spider couplings — elastomer degradation within 12 months was our consistent experience. WH4 cast-iron construction has now passed 3 years across 24 weaving-machine frames with zero unplanned coupling events. The annual grease repack is the entire maintenance footprint. Outstanding value-for-money for our production environment.”
★★★★☆
Vanuatu — Food-Processing Plant
Used in: Conveyor-head drive coupling on a vegetable-processing production line.
Feedback: “High-washdown-frequency environment with daily cleaning cycles. The WH4 has handled 3 years of continuous production with one slider replacement during a planned line shutdown. Knock one star only because we needed clearer guidance on the appropriate coupling-guard specification for our specific washdown pressure class — engineering team clarified quickly but it would be useful as part of the standard food-processing documentation pack.”
Frequently Asked Questions
How does the WH4 compare to a spider coupling at this size?
At the 160 N·m / 5 700 rpm envelope, spider couplings offer lower cost and simpler installation but introduce elastomer-fatigue degradation (typically 12–36 months in industrial ambient), speed-dependent vibration characteristics from the spider element, and a progressive-to-sudden failure mode that can be difficult to detect before catastrophic elastomer fracture. The WH4 offers a metallic slider with gradual, inspectable wear, consistent performance across the operating temperature and speed range, and a 5–8 year typical slider service interval. For retrofit applications where elastomer life has been unsatisfactory, the WH4 is the documented economic alternative.
Is the WH4 suitable for VFD-controlled drives?
Yes. VFD-controlled fan and pump drives typically operate across a speed range from 10 % to 100 % of rated speed, with soft-start ramp profiles that are well within the WH4’s torque envelope. The metallic slider does not exhibit the frequency-dependent stiffness change that spider-coupling elastomers introduce across speed ranges, providing consistent torsional characteristics across the full VFD operating window.
What is the recommended grease specification for high-humidity environments?
For high-humidity tropical or coastal environments, specify a calcium-sulfonate complex grease (e.g., Klüber Klüberplex BEM 34-132 or equivalent) rather than the standard lithium-complex grease. Calcium-sulfonate grades offer superior water-resistance and corrosion-inhibition for the cast-iron and steel interface. Annual repack interval remains appropriate; in extreme high-humidity applications (above 90 % RH continuous), 6-monthly repack is the engineering recommendation.
Can the WH4 hub be supplied bore-only for retrofit?
Yes. For retrofit applications where the existing slider is serviceable, WH4 hubs can be supplied individually with the specified bore and keyway. Hub-only supply is the most economical retrofit path when the existing coupling slider shows less than 50 % wear. Slider-only supply is also available for maintenance replacements where the existing hubs are dimensionally acceptable. Please specify bore, keyway width, and keyway depth at order entry.
What food-processing coupling-guard specification is recommended?
For food-processing applications with daily CIP/washdown cycles, an IP66-rated coupling guard in 304 or 316L stainless steel is the engineering recommendation. The guard should incorporate drainage slots at the lowest point to prevent condensate pooling, and the guard-to-shaft sealing should use FDA-grade silicone-foam gasket material. Ever-power can recommend suitable coupling-guard suppliers compatible with the WH4’s OD envelope on engineering enquiry.
Quote WH4 for Mid-Speed Light-Industrial Drives
For industrial-fan main, mid-sized process-mixer, textile-machine, conveyor-head, pharma light-mixing, and retrofit-legacy applications in the 160 N·m mid-speed class, the WH4 is the most cost-effective metallic-slider flexible-coupling specification available. Browse the wider WH series catalogue, read about Ever-power’s light-industrial supply capability, or enquire directly below.