The M3PHT70 torque arm gear reducer brings shaft-mounted mounting to the size 70 frame, where belt conveyors, dryer drums and rake mechanisms run loaded for most of the day. The hollow low-speed shaft takes the driven machine shaft directly - keyed or clamped with a shrink disc - and a torque arm carries the reaction torque back to the structure. The gearing is the standard three-stage all-helical train on parallel axes, case-hardened and ground, inside the horizontally split cast-iron housing shared across the industrial range.
Mid-Ladder Torque, Still Mountable on the Machine Shaft
Size 70 sits where the step from compact frames to plant-standard torque happens, and at this point many drives still benefit from hanging the gear unit on the machine shaft instead of building a plinth beneath it. The shaft-mounted layout removes the output coupling and the pedestal from the parts list and keeps the drive footprint on the machine itself. Bearing spans at this frame are sized for the overhung pull of a head pulley, so the absence of a base frame does not cost anything in load capacity.
M3PHT70 Designation Decoded
| M3 | Industrial gear unit family with three helical stages |
| P | All-helical gearing on parallel axes (R would add the bevel right-angle input) |
| H | Hollow low-speed shaft, keyed fit or shrink-disc connection (S marks a solid shaft) |
| T | Torque-arm mounting; the unit hangs on the machine shaft and reacts through the arm (F marks foot mounting) |
| 70 | Frame size 70 in the horizontal range 50 to 90 |
Each letter is an independent ordering decision, so the same size 70 housing exists as a foot-mounted solid-shaft unit, a foot-mounted hollow build or this torque-arm arrangement. That is what lets a plant keep one dimension ladder while the installation style changes drive by drive.
The service conditions this frame is selected for:
- Belt conveyor head and take-up drives on long overland runs
- Drag chain and scraper conveyor drives in grain terminals
- Drum drives on rotary dryers and conditioning drums
- Thickener and clarifier rake drives with centre column mounting
- Screw conveyor drives on long troughs with swing-out tensioning
- Travel drives on medium-duty gantry and portal structures
Torque-Arm Practice on Continuous Drives
On conveyor duty the torque arm does more than react torque: it is the swing point for belt tensioning, so the whole drive package can be moved periodically to keep the belt tight without touching the gear alignment. On drum drives and rake mechanisms the arm simply anchors the reaction to the nearest structural member. Either way the unit rides on the machine shaft, so the shaft must be short and stiff enough to carry the gear unit - a condition worth checking against the outline drawing before the order, and one WGT verifies for every enquiry.
Enquiry and Supply
WGT issues the M-series catalogue and the size 70 outline drawing as PDF downloads, so the bore diameter, keyway or shrink-disc seat and the torque-arm bracket can be checked against the machine shaft up front. Send the driven machine, the motor power and speed, the required output speed, the shaft diameter and the daily running hours; the selection is verified against those inputs, quoted in writing, factory-tested and packed in an export wooden crate under a one-year warranty.
Questions We Hear Most Often
What inspection access does the housing provide?
The horizontally split housing opens along the shaft centreline, so gearing and bearings can be examined without removing the unit from its foundation. Covers give access to the oil galleries and bearing seats during service.
Can you supply vertical-shaft versions?
Yes. Vertical builds of the same industrial family cover the smaller size band and are common on vertical mixers, agitators and clarifier drives. State the orientation when ordering so oil levels and breathers are set correctly.
What documentation comes with an industrial gear unit?
Every shipment carries an installation manual, a dimension drawing, the nameplate data and a bench test record covering noise, temperature rise and backlash. Material certificates for shafts and gearing are available on request.
Choosing the Right Frame Size
| Model | Centre distance | Output | Typical duty |
|---|
| 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 |
| M3PSF90 | size 90 | solid shaft, foot | mill and kiln drives |
| 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: Belt conveyor head drive
Take a 75 kW motor at 1485 rpm driving a belt conveyor head shaft at 24 rpm. The ratio follows directly: 1485 / 24 = 61.9, so a ratio near i=62 is selected. In this case the hollow bore carries the head shaft directly and the torque arm lets the whole drive swing to tension the belt. 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
Ship loader slew drive
A port terminal selected heavy-duty gear units for the travel drives of its ship loader. Salt-laden air is handled by the heavy-duty coating option, and spare seal kits are held on site for the annual service.
Sugarcane carrier drive
A sugar mill drives its cane carriers with industrial gear units sized for fully loaded starts. The generous torque margin covers cane jams, and the right-angle build keeps the motor clear of the carrier slat path.
![right angle gearbox duty points overview]()
An overview of the duty points this series is built for.
OEM Framework Pricing and Reserved Capacity
Building machines in series? 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.
For OEM programmes we hold framework prices and reserve production slots for scheduled call-offs, so your line never waits on a gearbox. Ask for the framework terms with your first enquiry. Looking for a gearbox for belt conveyor? Tell us the duty point and we will confirm the model in writing.
