Type SF
Steel-body fluid couplings — extremely robust constant-fill, fixed-speed couplings built for mining and other sites where rugged simplicity matters.
Steel construction, proven since 1976.
The Fluidomat Type SF is a steel-body fluid coupling of extremely robust construction, supplied with a driving plate on one end and a metallic-disc flexible coupling on the other. It is a radially displaceable coupling that transmits power smoothly between motor and machine through a body of oil.
SF couplings are ideal for use in underground or opencast mines — and on any site where the use of aluminium is prohibited, or where robust construction with simplicity is necessary. They have been manufactured by Fluidomat since 1976 and are very well proven across a wide range of mining and surface applications.

Key data
Why engineers specify Type SF
- Virtually no-load start and run-up of the motor, with full use of motor peak torque for load acceleration
- Smooth and controlled acceleration of the driven machine
- Quick decay of the motor starting-current kick
- Adjustable starting characteristics to match the driven load
- Dampening of shock loads, torsional fluctuations and vibrations
- Rugged steel body suited to mining and abrasive environments where aluminium is not permitted
Built for the harshest sites.
Each SF coupling carries a driving plate on one end and a metallic-disc flexible coupling on the other, accommodating misalignment between motor and machine while passing torque through the working circuit of oil. The radially displaceable design keeps installation and alignment simple.
Because the housing is fabricated entirely in steel, SF couplings withstand the impact, dust and vibration of opencast and underground operations — and meet site rules that prohibit aluminium. Decades of field service since 1976 confirm their reliability on mining and surface drives alike.
Where SF earns its keep
For crushers, conveyors, fans and pumps on mine sites, the SF coupling protects the motor and gearbox from shock and stall while letting a squirrel-cage motor start on light load. The steel body and fusible-plug overload protection give a simple, fool-proof drive in demanding conditions.
Rating table — SF
Maximum ratings in KW at different input speeds (RPM). For final selection, please consult Fluidomat application engineering.
| Model | 600 | 750 | 900 | 1000 | 1200 | 1500 | 1800 |
|---|---|---|---|---|---|---|---|
| SF-4 | 1 | 1.8 | 3 | 4 | 8 | 15 | 22 |
| SF-6 | 2.6 | 5 | 9 | 12 | 20 | 40 | 60 |
| SF-7 | 4 | 7.5 | 13 | 18 | 31 | 60 | 80 |
| SF-8 | 5.6 | 11 | 19 | 26 | 45 | 80 | 114 |
| SF-9 | 10 | 19 | 33 | 45 | 78 | 152 | 197 |
| SF-10 | 14.4 | 28 | 48 | 66 | 115 | 224 | 290 |
| SF-566 | 20 | 40 | 68 | 93 | 161 | 315 | 375 |
Full dimension tables, connected flexible-coupling data, dry weights and oil quantities are available in the SF catalogue.
Technical specification & dimensions
Full dimension, connected-flexible-coupling, brake-drum and mass-moment-of-inertia data, as published by Fluidomat.
Dimension TABLE: SF
| Fluid Coupling Model SF | ØA | B | Ød1 Max | l1 | Ød4 Max | l4 | Flex Coupling Model FXC | Dry Wt. Kg | Max Filling Liters |
|---|---|---|---|---|---|---|---|---|---|
| 4 | 375 | 250 | 50 | 80 | 55 | 70 | II | 55 | 4.8 |
| 6 | 418 | 267 | 75 | 110 | 90 | 95 | III A | 82 | 7.8 |
| 7 | 470 | 300 | 75 | 110 | 90 | 95 | III | 98 | 10.0 |
| 8 | 508 | 310 | 75 | 110 | 90 | 95 | III | 106 | 13.5 |
| 9 | 570 | 330 | 110 | 140 | 110 | 110 | III | 190 | 18.75 |
| 10 | 620 | 345 | 110 | 140 | 110 | 125 | IV | 205 | 27 |
Connected Flexible Coupling
| Flexible Coupling Model | Internal Hub | External Hub | Pad Type Coupling | ||||||
|---|---|---|---|---|---|---|---|---|---|
| ød1 Max. | Ø 1 | L1 | ød2 Max. | Ø 2 | L2 | ød3 Max. | Ø 3 | L3 | |
| FFX-1 | 42 | 67 | 67 | 60 | 75 | 130 | — | — | — |
| FFX-3 | 80 | 92 | 72 | 90 | 110 | 170 | — | — | — |
| FFX-4 | 90 | 102 | 87 | 100 | 120 | 195 | — | — | — |
| FFX-5 | — | — | 125 | 150 | 230 | — | — | — | |
| FP-1 | — | — | — | — | — | — | 100 | 110 | 120 |
| FP-2 | — | — | — | — | — | — | 140 | 115 | 167 |
Diagrams & views





Proven on mining & surface drives
Need a rugged coupling for a mining drive?
Send us your motor rating, speed and driven-machine details and our engineers will recommend the right Type SF model.