NMRV Series
Combination Gearboxes
Two worm stages in series for very high reduction in one drive.
Double-reduction units built by coupling two worm gearboxes through a machined adaptor. Ratios run from 100:1 to 10000:1, which is the band a single stage cannot reach — the answer wherever the driven shaft has to turn at a few revolutions a minute.
- Power range
- 0.18 kW to 15 kW
- Ratio range
- 100:1 up to 10000:1
- Frame sizes
- NMRV 30 to 150
- Drive angle
- 90 degrees
Built for Duty
What separates the NMRV Series from a general-purpose drive.
Ratios a single stage cannot reach
Two worm sets in series multiply the reduction, taking output speed down to single-figure rpm from a standard four-pole motor.
Built from stock stages
Both halves come from the RW range, so the ratio is made up from parts a plant already stocks rather than a special.
Machined adaptor housing
The two bodies join through a machined flange, holding concentricity so the intermediate shaft runs true.
Strongly self-locking
At these ratios the drive will not back-drive, which is what suits it to hoists, gates and holding duty.
Compact for the reduction
Two right-angle stages fold the drive train into far less space than an equivalent multi-stage in-line box.
Universal mounting
Foot, flange and hollow or solid output shaft on the same unit, in either hand of rotation.
Selection data
Technical Specifications
Combination gearboxes — stage pairing against ratio and power
| Combination | Input stage | Output stage | Ratio range | Power range |
|---|---|---|---|---|
| NMRV 30 / 63 | NMRV 30 | NMRV 63 | 100:1 to 2000:1 | 0.18 kW to 0.55 kW |
| NMRV 40 / 75 | NMRV 40 | NMRV 75 | 100:1 to 3000:1 | 0.18 kW to 1.5 kW |
| NMRV 50 / 90 | NMRV 50 | NMRV 90 | 100:1 to 5000:1 | 0.25 kW to 3 kW |
| NMRV 63 / 110 | NMRV 63 | NMRV 110 | 100:1 to 7500:1 | 0.55 kW to 7.5 kW |
| NMRV 75 / 150 | NMRV 75 | NMRV 150 | 100:1 to 10000:1 | 1.1 kW to 15 kW |
Figures are for selection guidance. Confirm the final rating against the service factor for your duty cycle — send us the application and we will do it with you.
Where the NMRV Series Runs
- Hoists and lifting gear
- Rotary tables and indexing
- Sludge and clarifier drives
- Dosing and feeder screws
- Roller shutters and gates
- Slow-speed agitators
Also consider
Related Products
RW Series
Worm Gearboxes
- Power range
- 0.18 kW to 15 kW
- Ratio range
- 7.5:1 up to 100:1
Electric
Motors
- Power range
- 0.5 hp to 5 hp
- Speeds
- 960, 1440 and 2880 rpm
RK Series
Heli-Bevel Gearboxes
- Power range
- 0.37 kW to 55 kW
- Ratio range
- 6:1 up to 200:1
Quote the NMRV Series
Send the power, input speed, required output speed and the driven machine. We will confirm the frame, ratio and mounting, and price it.