The M3PSF90 industrial gear unit is the largest horizontal frame in the M-series foot-mounted range. A three-stage helical train on parallel axes, a horizontally split cast-iron housing and a foot-mounted solid output shaft carry the heaviest continuously rated duties a plant will hand to a gear drive: finish mill drives, pelletising plant, concentrator agitators and quay crane travel. Where right-angle routing is not needed, this is the frame that anchors the drive train.
The Top Frame of the Horizontal M-Series Line
Across the M-series the letters describe function and the number describes size: 50 through 90 in the horizontal build. Size 90 sits at the top of that ladder, so it is the frame chosen when a duty point is beyond what size 70 or 80 can carry without derating. At this scale, selection is driven less by headline gear rating and more by whether the housing can reject heat on three-shift operation, whether the slow-speed shaft can take the overhung load from a belt pulley, and whether the bearings will reach the next planned shutdown.
What Changes at Size 90
| Housing | Cast iron, horizontally split so gearing can be inspected without lifting the gear unit off its foundation |
| Low-speed shaft | Large-diameter solid shaft, keyed for a heavy coupling; hollow variants available in the same housing |
| Gearing | Case-hardened, ground helical teeth in all three stages, so efficiency holds across the ratio band |
| Thermal capacity | Oil sump and cooling surface sized for continuous full-load running rather than intermittent peaks |
| Mounting | Foot mounted to industry-standard foundations; torque-arm and vertical builds are separate codes |
Decoding M3PSF90
| M3 | Industrial gear unit family with three gear stages |
| P | All-helical, parallel-shaft layout (the R code adds a bevel stage for a right-angle drive) |
| S | Solid low-speed shaft (H marks a hollow shaft, keyed or shrink-disc) |
| F | Foot mounting (T marks a torque-arm build) |
| 90 | Frame size, the largest in the horizontal industrial range |
Because the code separates function from size, a plant can move up or down the size ladder while keeping the same mounting concept, the same shaft connection and the same maintenance routine - which is what makes one industrial family workable as a site standard.
The service conditions this frame is selected for:
- Cement finish mills and central drive ball mills
- Iron ore pelletising plant and disc pelletiser drives
- Copper and gold concentrator flotation agitators
- Ship unloaders, barge loaders and quay crane travel drives
- Lime kiln and clinker cooler drive trains
- Heavy mining slurry pumps and thickener rakes
Specification Support and Supply
WGT issues the M-series catalogue and the size 90 outline drawing as PDF downloads, so shaft height, bolt pattern and coupling fit can be verified against the existing foundation before any order is placed. Send the driven machine, the motor power and speed, the required output speed and the daily running hours; the rated torque is checked against those figures and a written quotation follows. Units are factory-tested, crated for export and covered by a one-year warranty.
Questions We Hear Most Often
What is the difference between a keyed hollow shaft and a shrink-disc connection?
A keyed hollow shaft is the economical choice for normal torque and easy maintenance. A shrink-disc connection transmits higher torque with zero backlash and no keyway wear, and is preferred for reversing or high-torque duties.
Can I get a CAD drawing or 3D model for my design review?
Yes. Send us the model and ratio and we provide a 2D dimension drawing and a 3D STEP model for your review, usually the same working day. Drawings follow the layout of the original series so they drop into your existing assembly.
What is the recommended oil change interval?
The housing is lubricated for life under normal duty and normal ambient. In hot, humid or continuous service, change the oil after the first 400 running hours and then every 4000 hours, or once a year, whichever comes first.
Choosing the Right Frame Size
| Model | Centre distance | Output | Typical duty |
|---|
| M3PSF90 | size 90 | solid shaft, foot | mill and kiln drives |
| M3PSF50 | size 50 | solid shaft, foot | conveyors, feeders |
| M3PSF60 | size 60 | solid shaft, foot | crushers, mixers |
| M3PSF70 | size 70 | solid shaft, foot | ball mills, shredders |
| M3PSF80 | size 80 | solid shaft, foot | kilns, heavy conveyors |
| M3RSF50 | size 50 | solid shaft, foot, right-angle | inclined conveyors, elevators |
| M3RSF60 | size 60 | solid shaft, foot, right-angle | screw classifiers, feeders |
| M3RHF70 | size 70 | hollow shaft, foot, right-angle | agitators, drum drives |
| M3PHT80 | size 80 | hollow shaft, torque arm, parallel | shaft-mounted conveyors |
| M3RHT90 | size 90 | hollow shaft, torque arm, right-angle | heavy shaft-mounted drives |
One family, two layouts. Choose P for a coaxial-in / parallel-out drive train, R when the motor must turn 90 degrees; then pick the shaft type and mounting style that the machine interface needs.
Selection Example: Typical duty point
A quick worked example using this frame: Motor speed divided by the target output speed gives the ratio, rounded to the nearest available step, and the required torque with the service factor then fixes the frame size. It always comes down to those three figures. Send them over and we confirm the frame, ratio and service factor in writing.
![online gearbox selection system workflow]()
Selection workflow used by our engineers for every quotation.
Real-World Duty Points
Cement plant clinker belt
A cement plant drives its clinker transport belt with reducers in dusty, high-ambient conditions. Sealed housings and a 40 deg C maximum temperature rise let the units sit close to the kiln without extra cooling.
Paper mill pulp agitator
A paper mill uses reducers on pulp chest agitators. Continuous 24-hour duty is handled by lifetime lubrication, and the low backlash keeps the agitator steady when the stock consistency changes.
![right angle gearbox duty points overview]()
An overview of the duty points this series is built for.
Your Selection, Cross-Checked by an Engineer
Send the numbers, get the model. Use the WGT Motor & Gearbox Online Selection System to turn your motor data into a model number, and we will quote that exact unit within the day.
Every enquiry is checked by an engineer against the rating tables before it is quoted, so the unit we recommend carries a real torque margin - not just a catalogue guess. Spare-unit and OEM volumes are both welcome. Looking for a gearbox for wastewater treatment? Tell us the duty point and we will confirm the model in writing.
