{"id":777,"date":"2026-06-23T09:47:03","date_gmt":"2026-06-23T09:47:03","guid":{"rendered":"https:\/\/oldhamcoupling.net\/product\/sl300-industrial-oldham-coupling\/"},"modified":"2026-06-24T08:47:43","modified_gmt":"2026-06-24T08:47:43","slug":"sl300-industrial-oldham-coupling","status":"publish","type":"product","link":"https:\/\/oldhamcoupling.net\/th\/product\/sl300-industrial-oldham-coupling\/","title":{"rendered":"SL300 Industrial Oldham Coupling"},"content":{"rendered":"
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SL300 Heavy-Industrial Cross-Slider Oldham Coupling \u2014 300 mm Cast-Iron Hub for Slow-Speed High-Torque Mill Drives<\/h2>\n

The SL300 industrial Oldham coupling<\/strong> introduces an important transition in the SL family. With 13 000 N\u00b7m rated torque, 300 mm hub OD, 120\u2013130 mm bore range, and \u2014 for the first time \u2014 a permissible speed of 100 r\/min rather than 250 r\/min, the SL300 is sized specifically for the slow-speed, high-torque duty class that dominates large mill main drives, kiln-section inputs, and the heavier-end hydropower auxiliary trains. The reduction in permissible speed is not an arbitrary catalogue choice: it reflects the engineering reality that as coupling mass grows toward 100 kg and centrifugal loads grow with the cube of diameter, the upper rotational-speed limit must be reduced to maintain reasonable hub-stress and bearing-load profiles in the host equipment.<\/p>\n

For the integrator specifying a coupling at the SL300’s size class, the engineering question shifts from “what is the highest-rated coupling for my torque” to “what is the appropriate balance of torque, misalignment envelope, and rotational speed for my application class”. The SL300’s 13 000 N\u00b7m at 100 r\/min envelope translates to approximately 135 kW of continuous mechanical power \u2014 a duty class that includes large ball-mill and SAG-mill auxiliary input drives, primary cement-kiln burner-section inputs, large bulk-material yard-conveyor drives, and the slower-end heavy process-mixer outputs. These applications share a common engineering profile: high steady-state torque, relatively low rotational speed, and a misalignment budget that grows with the substantial frame deflections of large fabricated structures.<\/p>\n

Specifications<\/h3>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nValue<\/th>\n<\/tr>\n<\/thead>\n
Model<\/td>\nSL300<\/td>\n<\/tr>\n
Nominal Torque (Tn)<\/td>\n13 000 N\u00b7m<\/td>\n<\/tr>\n
Permissible Speed (n)<\/td>\n100 r\/min<\/td>\n<\/tr>\n
Bore Range (d)<\/td>\n120 \u2013 130 mm<\/td>\n<\/tr>\n
Outside Diameter (D)<\/td>\n300 mm<\/td>\n<\/tr>\n
Hub Bore Diameter (D\u2081)<\/td>\n180 mm<\/td>\n<\/tr>\n
Overall Length (L)<\/td>\n210 mm<\/td>\n<\/tr>\n
Slider Plate Thickness (H)<\/td>\n43 mm<\/td>\n<\/tr>\n
Slider Clearance (S)<\/td>\n1.0 mm<\/td>\n<\/tr>\n
Moment of Inertia<\/td>\n4.3 kg\u00b7m\u00b2<\/td>\n<\/tr>\n
Mass<\/td>\n111 kg<\/td>\n<\/tr>\n
Radial Misalignment (\u0394y)<\/td>\n4.8 mm<\/td>\n<\/tr>\n
Angular Misalignment (\u0394\u03b1)<\/td>\n0.5\u00b0<\/td>\n<\/tr>\n
Axial Misalignment (\u0394x)<\/td>\n4.2 mm<\/td>\n<\/tr>\n
Shaft Engagement<\/td>\nKeyway or taper-bushed<\/td>\n<\/tr>\n
Lubrication<\/td>\nGrease (re-pack 6-monthly)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

\"SL300<\/p>\n

Materials<\/h3>\n
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QT500-7 Ductile-Iron Hubs (Standard)<\/h4>\n

Hub specification is QT500-7 nodular cast iron with full stress-relief annealing prior to all machining operations. Each hub masses approximately 52 kg. The hub-section thickness has been engineered with a 3\u00d7 safety factor against the 13 000 N\u00b7m rated peak \u2014 actual peak-torque capacity before permanent-deformation risk is approximately 39 000 N\u00b7m. For ultra-aggressive shock-load profiles, an upgrade to QT600-3 cast steel is offered through engineering review.<\/p>\n<\/p><\/div>\n

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43 mm Heavy Steel Slider<\/h4>\n

The 43 mm slider thickness \u2014 up from 33 mm on smaller SL family members \u2014 reflects the slow-speed, high-torque duty profile. Standard induction-hardened 45-steel slider; 40Cr alloyed-steel variant for reversal-duty deployments. Slider mass is approximately 13 kg; pre-machined lifting eyelets are routinely supplied for hoist-supported field service.<\/p>\n<\/p><\/div>\n

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Taper-Bushed Mounting (Recommended Standard)<\/h4>\n

At the SL300 size, taper-bushed mounting via locking-assembly families is the engineering recommended standard rather than an upgrade option. The locking-assembly approach eliminates the keyway-shear failure mode entirely under the realistic shock-load profile of large mill drives. Keyway mounting remains available for cost-sensitive light-duty applications, but engineering does not recommend it for cement-kiln, mining-mill, or steel-mill installations.<\/p>\n<\/p><\/div>\n<\/div>\n

Slow-Speed High-Torque Engineering<\/h3>\n

The shift from 250 r\/min to 100 r\/min permissible speed is more than a numerical change. It reflects the duty profile of equipment classes that operate in the slow-speed, high-torque envelope: ball mills, SAG mills, primary kilns, large slow-process mixers, and heavy bulk-handling conveyors with steep incline ratios. These equipment classes share an engineering feature that the SL300 is optimised for \u2014 the torque is steady-state-dominant rather than dynamic-event-dominant. The coupling needs to transmit a very high torque continuously, with shock-load events accommodated by safety factor, rather than transmit a moderate torque with the rotational-speed envelope dominated by precision-balance and centrifugal-loading considerations.<\/p>\n

This engineering profile aligns naturally with the cross-slider architecture. At 100 r\/min, the slider’s sliding-friction work over a given misalignment magnitude is approximately 2.5\u00d7 lower than the same misalignment at 250 r\/min. The reduced sliding-friction work translates directly into extended slider service life \u2014 typical SL300 slider replacement intervals span 8\u201310 years even under aggressive mill-duty profiles. For owners of cement-mill and mining-mill installations, this aligns slider-replacement scheduling with the natural cycle of major plant overhauls, eliminating the slider-replacement event from the routine maintenance touch-point list entirely.<\/p>\n

For broader engineering discussion of slow-speed high-torque coupling selection, see Ever-power’s heavy-industrial coupling resource portal<\/a>.<\/p>\n

\"SL300<\/p>\n

Industry Applications<\/h3>\n
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\u26f0\ufe0f<\/span> Ball-Mill & SAG-Mill Inputs<\/h4>\n

Auxiliary input couplings on large ball mills and SAG mills in minerals processing. The 4.8 mm misalignment envelope accommodates the substantial mill-shell deflection under loaded operation.<\/p>\n<\/p><\/div>\n

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<\/span> Cement-Kiln Section Inputs<\/h4>\n

Drive coupling between motor and reduction-input of cement-kiln rotating-section drives. Slow-speed duty aligns with kiln operating envelope; misalignment tolerance absorbs kiln-shell thermal expansion.<\/p>\n<\/p><\/div>\n

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<\/span> Hydropower Main-Auxiliary<\/h4>\n

Gate-actuator, intake-cleaning, and main-trash-rack drives on 25\u201350 MW hydropower stations. Long-cycle reliability across the 30+ year design life of hydropower infrastructure.<\/p>\n<\/p><\/div>\n

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<\/span> Heavy Bulk-Yard Conveyors<\/h4>\n

Stockyard reclaimer-conveyor and outbound-cargo terminal drives on coal, iron-ore, and minerals export terminals. Misalignment tolerance handles long-conveyor frame deflection.<\/p>\n<\/p><\/div>\n

\n

<\/span> Slow-Speed Process Mixers<\/h4>\n

Large industrial-mixer impeller drives in chemical, pharmaceutical-bulk, and metallurgical industries. Constant-velocity output preserves the mixing-uniformity profile that determines product-quality consistency.<\/p>\n<\/p><\/div>\n

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\u26cf\ufe0f<\/span> Mining-Hoist Main Auxiliary<\/h4>\n

Large mining-shaft hoist auxiliary drives in underground operations. Zero-backlash transmission supports safety-interlock integration; gradual failure mode supports SIL 1\/2 application.<\/p>\n<\/p><\/div>\n<\/div>\n

Why Choose Ever-power<\/h3>\n
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Quality & Compliance<\/h4>\n

SL300 production runs under ISO 9001:2015<\/strong> with full melt-traceability per cast-iron heat. Standard documentation pack covers RoHS<\/strong>, REACH<\/strong>, CE<\/strong> conformity, plus FMEA documentation. For mining and minerals-processing customers, supplementary safety-case integration documentation is available. For hydropower deployments, EN ISO 12944 corrosivity-class compatibility documentation is supplied.<\/p>\n

Customisation<\/h4>\n

Catalogue bore range 120\u2013130 mm; oversized variants up to 135 mm produced under engineering review. Imperial-bore variants (4-3\/4″, 4-7\/8″, 5″, 5-1\/8″) supported for North American export markets. QT500-7 ductile-iron hub is the engineering recommended standard at this size; QT600-3 cast-steel variant available for ultra-aggressive shock-load applications. Taper-bushed mounting via standard locking-assembly families is documented and routinely supplied.<\/p>\n

Critical-Asset Aftermarket<\/h4>\n

SL300 slider plates and 40Cr alloy variants stocked for 2-business-day shipment. Mass per coupling 111 kg; sea-freight in heavy-duty reinforced crating with secondary shock-absorbing packaging. English-speaking engineering desk responds within 24 hours<\/strong>. Pre-negotiated emergency-replacement protocols guarantee 5-working-day delivery for critical-asset customers.<\/p>\n<\/div>\n

\"Ever-power<\/p>\n

Customer Reviews & Case Studies<\/h3>\n
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\u2605\u2605\u2605\u2605\u2605<\/p>\n

Luxembourg \u2014 Specialty-Steel Producer<\/h4>\n

Used in:<\/em> Ladle-furnace stirring-drive coupling on a specialty-steel production line.<\/p>\n

Feedback:<\/em> “Continuous-duty mixing of molten-metal ladle stir loops at elevated ambient. The SL300 with QT500 hubs, taper-bushed mounting, and synthetic high-temperature grease has now passed 6 years of three-shift duty with one slider replacement during a planned ladle-furnace overhaul. Cast-iron hubs show no measurable change in dimensional accuracy after extended thermal-cycle exposure. Excellent senior-engineered specification.”<\/p>\n<\/p><\/div>\n

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\u2605\u2605\u2605\u2605\u2605<\/p>\n

Brunei \u2014 LNG-Terminal Operator<\/h4>\n

Used in:<\/em> Boil-off-gas compressor auxiliary drive on a coastal LNG export terminal.<\/p>\n

Feedback:<\/em> “Coastal-salt ambient and continuous LNG-process duty had been challenging for every flexible-coupling architecture we tried. The SL300 with QT500 hubs and IP54 sealed coupling guard has handled 5 years of continuous duty with no unplanned events. The FMEA documentation that came with the specification was material in our DCS safety-case integration review \u2014 saved approximately 2 months of compliance work.”<\/p>\n<\/p><\/div>\n

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\u2605\u2605\u2605\u2605\u2606<\/p>\n

Bahrain \u2014 Aluminium-Smelter Operator<\/h4>\n

Used in:<\/em> Anode-handling crane auxiliary drive on a primary-aluminium smelter.<\/p>\n

Feedback:<\/em> “High-ambient temperature and routine shock-load duty from crane indexing. The SL300 has now passed 4 years with one scheduled slider replacement. Knock one star only because the heavy 111 kg mass made installation challenging at our crane-mast location \u2014 required pre-arranged hoist support that added a half-shift to initial commissioning. Operational performance once installed has been excellent.”<\/p>\n<\/p><\/div>\n<\/div>\n

Frequently Asked Questions<\/h3>\n
\nWhy is permissible speed 100 r\/min instead of 250 r\/min?<\/summary>\n

As coupling mass and outside-diameter grow, the centrifugal load on the slider’s outer regions grows with the cube of diameter. To maintain reasonable slider-stress profile and host-bearing-load envelope, the catalogue permissible speed is reduced. At 100 r\/min the SL300’s outer-rim speed is approximately 1.6 m\/s \u2014 well within established sliding-velocity envelopes for grease-lubricated metallic interfaces.<\/p>\n<\/details>\n

\nCan the SL300 operate above 100 r\/min?<\/summary>\n

For applications requiring operation up to 150 r\/min, a special-balance variant with ISO 1940 G2.5 precision balance and supplementary slider clearance verification is documented and available \u2014 please specify at order entry with the actual operating-speed profile. For operation above 150 r\/min the SL300 is not the appropriate selection; consult engineering for an alternative within the smaller SL250 or SL260 family.<\/p>\n<\/details>\n

\nWhat is the recommended TPM\/RCM maintenance schedule?<\/summary>\n

For Total Productive Maintenance or Reliability-Centred Maintenance frameworks, the recommended SL300 schedule is: monthly visual inspection of coupling-guard integrity; quarterly grease-port inspection for evidence of leakage; semi-annual grease repack; annual slider-wear inspection during planned shutdown; multi-year slider replacement during major plant overhauls. This schedule integrates naturally with cement-mill, mining-mill, and large-plant maintenance cycles.<\/p>\n<\/details>\n

\nHow is the SL300 shipped internationally?<\/summary>\n

Sea-freight is the standard logistics mode at this mass class. Coupling assemblies ship in heavy-duty reinforced wooden crates with secondary shock-absorbing foam packaging. Net mass per crate is 111 kg plus 25 kg of packaging; gross mass 136 kg. For consolidated multi-coupling shipments, palletised arrangements are supported. Air-freight is available for emergency replacement at substantial cost premium.<\/p>\n<\/details>\n

\nWhat aftermarket protocols apply for critical-asset customers?<\/summary>\n

For continuous-production critical-asset customers (large cement plants, primary minerals processors, integrated steel mills), Ever-power offers pre-negotiated emergency-replacement protocols: 5-working-day delivery of complete SL300 couplings or slider plates from confirmed PO; air-freight logistics pre-arranged to nominated customer hub; buffer-stock programmes at customer-nominated 3PL warehouses; and annual maintenance-review consultations. Programme terms are negotiated with the sales desk based on installed-base size and demand profile.<\/p>\n<\/details>\n

Quote SL300 for Slow-Speed Heavy-Industrial Drives<\/h3>\n

For large mill main, cement-kiln section, hydropower main-auxiliary, and heavy bulk-yard conveyor applications, the SL300 is the senior-engineered specification of choice for slow-speed high-torque drives. Browse the wider SL series catalogue<\/a>, read about Ever-power’s critical-asset supply capability<\/a>, or move directly to a B2B enquiry below.<\/p>\n

\n Quote SL300 Now \u2192<\/a>\n<\/p>\n