The M3PHF50 hollow shaft gearbox takes the size 50 industrial housing and gives it a hollow output shaft, so the gear unit slides directly onto the driven machine shaft instead of driving through a coupling. The three-stage helical train on parallel axes is unchanged. What changes is the installation: no output coupling, no separate bearing pedestal, and a shorter drive train between the motor and the machine.
A Shaft-Mounted Build in the Size 50 Frame
Size 50 is the smallest horizontal frame in the industrial family, which makes it the practical choice for the many drives in a plant that are compact but still run continuously: screw conveyors, airlock feeders, small elevators and agitators. Standard industrial practice sizes 50 through 90 in the horizontal build, and every frame shares the same horizontally split cast-iron housing, case-hardened and ground helical gearing, and generous bearing spans for overhung loads.
The H and F Letters in Practice
| M3 | Three-stage industrial gear unit |
| P | Helical gearing on parallel axes; the R code marks the bevel-helical right-angle version |
| H | Hollow low-speed shaft - a keyed fit or a shrink-disc connection onto the machine shaft |
| F | Foot mounting; the T suffix swaps the feet for a torque arm where the machine shaft carries the unit |
| 50 | Smallest size in the horizontal industrial range (50 to 90) |
Reading the designation left to right tells an engineer the gear arrangement, the output connection and the way the unit is held in place - the three decisions that most often change between one installation and the next.
Hollow Shaft or Solid Shaft?
A hollow output removes the coupling and the pedestal bearing that a solid-shaft unit needs, which shortens the machine and cuts alignment work on site. The trade-off is that the gear unit now rides on the machine shaft, so the mounting must suit: a foot-mounted hollow-shaft unit is bolted to a bracket, while a torque-arm build reacts the drive torque through a rod and needs no foundation at all. For conveyors, elevators and agitators where the driven shaft is short and stiff, the shaft-mounted arrangement is usually the simpler and cheaper installation.
Process lines where this build is the standard choice:
- Shaft-mounted screw conveyors on a hollow output shaft
- Belt conveyor head pulleys driven through a shrink disc fit
- Bucket elevator head shafts with a keyless connection
- Rotary airlock and rotary valve drives for bulk handling
- Drum and paddle agitators without an intermediate coupling
- Slewing and travel drives on stackers and reclaimers
Selection and Ordering
WGT ships the M-series catalogue and the size 50 outline drawing as PDF downloads so the hollow-shaft bore, keyway or shrink-disc seat and the mounting pattern can be checked against the machine shaft before the order. To confirm a selection, send the driven machine, the motor power and speed, the required output speed, the shaft diameter and the running hours per day. The unit is verified against those inputs, quoted in writing, factory-tested, packed in an export wooden crate and covered by a one-year warranty.
Selection Example: Typical duty point
Say the customer needs a slow, steady output from a standard four-pole motor. 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. Work through the same three steps - speed, output speed, torque - and the model number falls out; we verify it against the duty class before quoting.
![gear reducer ratio calculation steps]()
From duty point to model number - the same four steps every time.
Applications in Industry
Mining slurry pump drive
At a mineral processing site, hollow-shaft reducers drive slurry pump agitators. The hollow bore takes the pump shaft with no coupling, so a pump change-out no longer means re-aligning a separate drive.
Palm oil mill fruit elevator
A palm oil mill powers its fruit elevator with reducers. The humid, oily atmosphere is handled by FKM seals, and the compact frame fits between the steriliser and the threshing drum.
![gear reducer industries served - WGT]()
Industry map: the sectors where the M3 series is most common.
Buyer Questions and Answers
What paint finish and corrosion protection is applied?
Housings are shot-blasted and finished with a two-component industrial paint in RAL colours, giving good protection for indoor and sheltered outdoor duty. For aggressive or coastal sites, ask for the heavy-duty coating option.
Do you supply spare parts such as seals and bearings?
Seal kits, bearings, output shafts and covers are available from stock or on short lead time. We keep the drawings for every unit we ship, so a replacement part ten years from now is still traceable to your original order.
M3 Series Model Overview
| 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 |
The series is sized for continuous heavy duty rather than by motor power alone: the required torque with the service factor decides the frame, and the stage count (2 to 5) decides the ratio band.
Fast Quotation for OEM and Repeat Orders
Buying one unit or one hundred? Run your duty point through the WGT Motor & Gearbox Online Selection System first: it saves a round of emails and gets you to a firm price faster.
Single units ship on the same production route as batch orders, with no minimum-order surcharge. For OEM programmes we hold framework pricing and reserve capacity for your scheduled call-offs. Looking for a gear reducer for food processing machine? Tell us the duty point and we will confirm the model in writing.
