10 sizes · up to 1,550Nm · ratios 5 to 100:1 single worm, to 5,000:1 combined · hollow bore 11 to 50mm · up to 18.5kW
The NMRV is Motovario’s square body worm gearbox and the core of its VSF worm series, in ten sizes from 025 to 150: NMRV in sizes 025 to 050, 130 and 150, and NMRVpower (NMRV-P) in sizes 063 to 110. Add a helical pre-stage or a second worm stage for higher ratios, and choose from IEC motor flanges, a solid input shaft and a wide range of hollow bores and mounting accessories.
A worm gearbox turns the drive through 90 degrees in one compact stage, with a high reduction ratio and quiet running. The NMRV is built in ten sizes, named by centre distance in millimetres from 025 to 150. Casings are die-cast aluminium alloy up to size 110 and G200 grey cast iron for sizes 130 and 150, finished in blue RAL 5010 epoxy-polyester powder from size 030. The worm has a ground ZI profile and the wheel is CuSn12Ni2 bronze.
Single worm units run from 5:1 to 100:1. For lower output speeds, a helical pre-stage takes the ratio up to 1,083:1 (HW on sizes 063 to 110, HA31 on sizes 040 and 050), and a second worm stage (double worm) up to 5,000:1. Nominal output torque runs from 22Nm on the NMRV030 to 1,550Nm on the NMRV150 at 1400rpm input, with radial loads up to 18,000N and motors up to 18.5kW.
Every size is supplied filled with synthetic oil for life; only sizes 130 and 150 have breather, level and drain plugs. Inputs include IEC motor flanges in B5 and B14 and a solid input shaft (NRV), and outputs include hollow bores from 11mm (NMRV025) to 50mm, output shaft kits, output flanges, a torque arm, a protective cover and a torque limiter. ATEX versions are available in categories 2GD and 3GD.
| Specification | NMRV / NMRV-P |
|---|---|
| Type | Worm gear reducer / geared motor (VSF series) |
| Sizes | NMRV 025, 030, 040, 050, 130, 150; NMRVpower (NMRV-P) 063, 075, 090, 110 |
| Nominal output torque | Up to 1,550Nm (Mn2 at 1400rpm input) |
| Ratios | Single worm 5:1 to 100:1 (030: to 80:1); HW and HA31 helical pre-stage up to 1,083:1; double worm 100:1 to 5,000:1 |
| Maximum radial load | 18,000N |
| Dynamic efficiency (1400rpm) | From about 0.9 at low ratios to about 0.5 at 100:1, depending on size and ratio |
| Input | IEC motor flange B5 or B14 (IEC 56 to 160 depending on size); NRV solid input shaft; HW and HA31 helical pre-stages |
| Power | Up to 18.5kW (worm geared motor tables 0.09 to 15kW) |
| Output | Hollow shaft 11 to 50mm; output shaft kit; output flange; torque arm; protective cover; torque limiter |
| Mounting | Universal (U) casing on sizes 025 to 075; feet, flange or shaft mounted with torque arm |
| Casing | Die-cast aluminium alloy (025 to 110); G200 grey cast iron (130, 150) |
| Gearing | ZI ground worm; CuSn12Ni2 bronze worm wheel |
| Finish | Blue RAL 5010 epoxy-polyester powder (size 030 and above) |
| Options | Viton seals, reinforced output, torque limiter, roller output bearings on request |
| Lubrication | Synthetic oil, lubricated for life; breather, level and drain plugs on 130 and 150 only |
| Design standards | ISO 14521, DIN 3996, BS 721, AGMA 6034, ISO 6336, DIN 3990, DIN 743, ISO 281 |
| ATEX | 2GD and 3GD versions (Zones 1/21 and 2/22) |
| Size | Centre distance (mm) | Nominal torque at 1400rpm (Nm) | Hollow bore (mm) |
|---|---|---|---|
| NMRV025 | 25 | Up to 17 (geared motor only, 0.09kW) | 11 |
| NMRV030 | 30 | 22 | 14 |
| NMRV040 | 40 | 48 | 18 or 19 |
| NMRV050 | 50 | 88 | 24 or 25 |
| NMRV-P063 | 63 | 160 | 25 or 28 |
| NMRV-P075 | 75 | 247 | 28, 30, 32 or 35 |
| NMRV-P090 | 90 | 432 | 35, 38 or 40 |
| NMRV-P110 | 110 | 725 | 42 |
| NMRV130 | 130 | 1,050 | 45 |
| NMRV150 | 150 | 1,550 | 50 |
Source: Motovario TECHNICAL CATALOGUE VSF / IEC / STD / EN / REV.0 / 2024 (worm geared motors: NMRV, NMRV-P, SW, SW-CD), with nominal torque Mn2 and ratio ranges from the NRV/ISW reducer tables at 1400rpm input, efficiency from the mesh data tables, bores from the dimension tables and lubrication from the quantity notes; cross-checked against the Motovario VSF product pages and Clean Duty brochure CLEAN DUTY/2021/REV.0/EN. Checked 2 November 2026.
For technical information, brochures and further product details, visit our downloads page.
NMRV is Motovario’s designation for its worm gearbox, and the number that follows is the size, which matches the worm centre distance in millimetres: an NMRV050 has a 50mm centre distance. NMRV-P, or NMRVpower, is the designation Motovario uses for sizes 063, 075, 090 and 110. NRV denotes the version with a solid input shaft.
It depends on the ratio. At 1400rpm input, an NMRV050 runs at about 0.89 efficiency at 5:1, 0.87 at 10:1 and about 0.5 at 100:1. Where efficiency matters, a helical pre-stage with a lower worm ratio, or a bevel helical gearbox, keeps losses down.
Higher ratios can be. A worm gearbox is statically irreversible when its static efficiency is below 0.5, which on most NMRV sizes happens from around 25:1 to 30:1 upwards. Vibration and shock can still allow back-driving, so use a brake motor where the load must be held.
No. Every size is supplied filled with synthetic oil for life. Only sizes 130 and 150 have breather, level and drain plugs, and the mounting position should be specified for those sizes and for some NMRV-P units.
Add a helical pre-stage to the input, HW on sizes 063 to 110 or HA31 on sizes 040 and 050, for ratios up to 1,083:1. For even lower speeds, combine two worm stages as a double worm unit, from 100:1 up to 5,000:1.
The casing. NMRV units have a square body; the SW Series has a compact round body but uses the same gearing, bearings, motor flanges and accessories as the NMRV, so ratings in the shared sizes are the same.
Browse NMRV worm gearboxes by size, ratio and bore, or send us the nameplate of the unit you are replacing and we will match it.
Contact
Betech 100pt Ltd
Four Square Buildings, Thomas Street
Heckmondwike, West Yorkshire, WF16 0LS
Telephone: 01924 411921
Email: sales@betech.co.uk
Opening hours: 8:00 to 17:00
