The M3RVHF70 vertical hollow shaft gearbox pairs a right-angle bevel input with a bored output in the 70 frame, so a process shaft travels through the housing while the motor sits to one side at deck level. Nothing is stacked above the machine and nothing is coupled below it: the drive train reduces to a single housing, one machined bore and a key or shrink disc. On large tanks, deep sumps and thickener centres that is the difference between a weekend service job and a crane booking.
What the 70 Frame Changes
Below this size a bored output is usually carrying modest shafts with short spans. At 70 the bearing set is sized for the moments that process shafts actually generate - a long agitator column, a pump line reaching down through several metres of water - and the bevel pair is proportioned so start-up torque does not become the limiting condition. The bore diameter grows with it, which lets the same unit accept heavier process shafts without a sleeve arrangement.
The frame also matters for maintenance access. Larger flanges mean larger clearance around bolt heads, and larger seal bores mean seals can be changed with ordinary hand tools rather than a hydraulic press and a machined drift.
Letter by Letter
| M | Three-stage industrial gear unit family |
| R | Bevel first stage with a side-fed motor |
| V | Upright build for a downward process axis |
| H | Bored output accepting a through-going shaft |
| F | Foot and flange fixing for headplate mounting |
| 70 | Frame size in the upright range |
The useful consequence is that the designation is a purchasing document, not a suggestion. Bore tolerance, keyway width, seal grade, flange drilling and breather position all follow from the code, and a unit ordered by the wrong final letter cannot be corrected with a different coupling.
The Parts That Set the Service Interval
On a bored vertical drive the teeth are seldom what stops the machine. The shaft seal sits directly above whatever the vessel contains, and the lower bearing takes the full reaction of the suspended shaft; those two components write the maintenance calendar. A standard lip seal handles clean water; over brine, slurry mist, solvent vapour or hot oil it is the wrong grade, and the first sign is usually a falling oil level rather than a rising vibration reading. Putting vapour, solids content and temperature on the enquiry form is the cheapest reliability measure available before the casting is ordered.
Ground helical stages keep losses and noise low, and the bevel pair is lapped as a matched set so backlash stays within tolerance over the working life. None of that rescues a seal chosen without reference to the process atmosphere.
Machine groups this unit is specified into: Agitators on brewery whirlpool vessels Vertical bore pumps on irrigation pump stations Flocculant make-up mixers in filter press houses Thickener raking mechanism drives at phosphate plants Circulation drives on crystalliser vessels Deep well pump heads on industrial water supply Condensate tank units in power plant make-up Vertical propellers on fish farm aeration ponds
Installation on an Operating Plant
Start with the headplate: flat, square, and bolted to structure that will not deflect under reaction torque. The process shaft is then raised through the bore to the agreed fit, end float set to drawing so the unit and process bearings share thrust as designed, and the key or shrink disc made up to the stated torque with a record kept. Fit the breather upright, read the oil level at rest, and turn the drive by hand before the first powered start. A hand turn that binds means a forced bore fit or a shaft out of true - both cheaper now than at running temperature.
Documentation and Spares
Every unit leaves with a dimensional drawing, an oil chart for the declared posture and a nameplate fixing frame, ratio and arrangement for repeat orders. The bore is plugged against dust and the crate holds the commissioning items a site needs on day one. Plants running several vessels of one pattern gain most by ordering a single frame across the board; spares, oil and training then occupy one line in the storeroom rather than six.
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
Pet-food extruder feeder
A pet-food plant chose reducers for the feeder screws ahead of its extruders. Steady torque at variable output speed keeps the kibble size consistent, and washdown sealing protects the unit during sanitation shifts.
Ceramic tile press feeder
A ceramic tile producer fitted reducers to press feeders. The dusty environment is handled by sealed housings, and the stable low-speed output stops the tile blanks shifting before pressing.
![gear reducer industries served - WGT]()
Industry map: the sectors where the M3 series is most common.
Buyer Questions and Answers
How often should the oil be changed in heavy duty?
With mineral oil, plan an initial change after the running-in period and then roughly every 5,000 hours. Synthetic oil stretches the interval to around 10,000 hours. Hot environments, dust or frequent starts shorten the interval - we advise the schedule with the quotation.
Can the unit be rebuilt instead of replaced?
Yes. Bearings, seals and gear sets are available as spare internals, and the horizontally split housing allows inspection and reassembly on site. Many operators overhaul units during annual shutdowns instead of buying new.
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.
Site Survey Data? We Size It for You
Have the machine data but not the model? 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.
Send the conveyor length, belt speed, drive pulley diameter or the machine duty description. We run the full selection - ratio, frame, service factor - and return the datasheet with the quote. Looking for a speed reducer for bucket elevator? Tell us the duty point and we will confirm the model in writing.
