The M3RVSF90 vertical bevel helical gear unit sits at the top of the upright right-angle family that is kept in stock, and it behaves like a small machine rather than a fitting. A ground spiral bevel pair turns the motor drive to the vertical, then two helical stages work the speed down to process level, all inside a cast housing that also serves as the structural base of the installation. On this frame the foot pads and headplate flange are machined in a single setup, so the shaft reference and the fixing reference cannot drift apart.
Duties That Belong on the 90 Frame
The 90 build earns its place when two limits meet at once: the torque is high enough that a smaller housing would run hot, and the process shaft is long enough that the bending moment at the output bearing dominates the design. Circular clarifiers, deep sump pump columns and large digester mixers all fall into that band. Working the frame choice from the moment curve first and the torque figure second is what keeps the seal and lower bearing in their comfortable zone for years.
There is also an economic side. Because the 90 is the largest upright frame the factory holds semi-standard, lead time on a configured unit is far shorter than on a fully custom build, and plants that standardise across vessels can share one dimensional drawing across a whole installation.
How the Marking Maps to the Hardware
| M | Industrial multi-stage gear unit family |
| R | Bevel stage at the input, drive turned 90 degrees |
| V | Vertical assembly, output shaft facing down |
| S | Solid ground output shaft with parallel key |
| F | Foot mounts plus machined flange for the headplate |
| 90 | Frame size, top of the stock upright range |
None of the letters says anything about speed. The frame fixes the casting and the shafts; the ratio is chosen separately to land the process speed, and the same frame accepts a wide ratio span. Enquiries are most useful when they arrive as duty data rather than as a model guess.
Keeping Oil Where It Should Be
A tall vertical housing divides its lubrication into a lower sump and an upper spray region fed by what the rotating gears fling upward. On the 90 frame that distance is at its greatest, so the fill level must be read with the unit level and at rest, against the quantity stamped on the plate - never by dipping a cold unit on a sloped plinth.
The breather deserves the same attention. A housing that swings between hot duty and cold standby pumps air in and out every cycle, and a breather sitting in a condensate pocket breathes moisture in with it. Mounting it high, and cleaning the cap during the first inspection round, prevents most of the emulsified oil cases that arrive for warranty review.
Service profiles this build is regularly chosen for: Circular clarifier rake drives in steelworks water circuits Vertical sump pumps in deep foundation dewatering Anchor stirrers in brewery and distillery fermentation halls Lime slaker drives at flue gas treatment plants Turntable drives on plate rolling line coil beds Gypsum slurry agitators in desulphurisation buildings Thickener duty in tailings reclaim water systems Cooling tower cell drives with long vertical shafts
Standing the Unit Up Correctly
The factory test runs the unit in its working posture and the crate arrives filled with oil, so site work is alignment, not assembly. Check the plinth or headplate for flatness across the full bolt circle, because a dished face tilts the housing and loads the output seal sideways from day one. Snug the fixing bolts in a star pattern, pull them to the tabulated torque, and only then bring the process shaft into the coupling so residual misalignment appears as shaft run-out rather than hidden housing stress.
Before power is applied, turn the train by hand through a full revolution - a bind at one angle points to a bent column or an off-centre steady bearing, not to the gearbox itself. Run unloaded, watch for weeping at the lower seal, confirm the upper stage is not running dry, then step the load up and log the steady-state oil temperature as the site baseline.
Information to Send With the Enquiry
Give the absorbed power or output torque, required output speed, overhung load with its point of application, shaft rotation, mounting posture, the medium in the vessel, ambient range and daily hours. Include the process shaft diameter and the fit at the coupling, since the gearbox side must suit hardware that already exists. A clear photo of the old nameplate plus a headplate sketch closes most open questions in one exchange.
Making the Next Order Easy
Keep the dimensioned drawing with the vessel file rather than in a closed project archive, and note the oil grade and seal type on the maintenance record. A repeat unit for an identical vessel can then be confirmed in one message, with the nameplate photo as the only cross-check. Plants that follow this habit typically move from enquiry to confirmed order for a spare upright drive in a fraction of the time of the first purchase.
Selection Example: Typical duty point
A typical enquiry for this frame reads like this: 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. That is the whole calculation. If your duty involves heavy starting, frequent reversing or many stops per hour, tell us and we raise the service factor.
Which Frame Size Do You Need?
| 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 |
Foot-mounted frames are listed below; torque-arm (T), hollow-shaft (H) and vertical (V) variants are available across the size range. Ask for the outline drawing to check the interface before ordering.
Answers to Common Questions
What tooth quality and grinding finish do you apply?
Gearing is case-hardened and profile-ground to international accuracy grades, with crowning and end relief applied to avoid edge loading. This is what keeps noise and vibration stable over years of continuous duty.
Can existing motors, couplings and guards be reused?
In most upgrade projects yes: because input and output interfaces follow the common industry dimensions, the existing motor, coupling and guard usually bolt straight on. Send the old nameplate and we confirm before you order.
What happens if my duty changes after installation?
Send us the new duty point. A revised torque and service-factor calculation is free of charge, and the answer is usually one of three: the unit is fine, add an oil change interval, or plan a frame change at the next shutdown.
![gearbox sizing steps for engineers]()
Four steps from your application data to a firm model number.
Case Notes from the Field
Cold-store conveyor
A cold-store operator uses reducers on freezer-room conveyors. Low-temperature synthetic oil and moisture-resistant seals keep the units running below -20 deg C ambient.
Bakery spiral cooler
A bakery equipment builder fits units to spiral cooler drives. The compact right-angle layout fits under the spiral cage, and food-grade lubrication was specified for the hygienic area.
![industrial gear unit application overview]()
A cross-section of the installations we supply every month.
Framework Stock for Critical Spares
Can your plant afford downtime? Try the WGT Motor & Gearbox Online Selection System, then send the result sheet - we return a complete datasheet, drawing and price the same day.
For critical drives we can hold finished units or long-lead internals against a framework agreement, ready to dispatch when your shutdown starts. Ask for the spares-coverage proposal. Looking for a gearbox for crusher? Tell us the duty point and we will confirm the model in writing.
