Worm Geared Motors & Speed Reducers (NMRV)

Overview

NMRV Worm Geared Speed Reducers

Worm geared motors are the world’s most popular solution for compact right-angle mechanical power transmission. Nairobi Power Engineers stocks the complete NMRV and NRV series worm gearboxes from size 025 up to size 150, supporting motor inputs from 0.06 kW to 15 kW.

Featuring lightweight die-cast aluminium alloy housings (sizes 025–090) or rugged cast iron (sizes 110–150), case-hardened alloy steel worm shafts, and centrifugally cast phosphor bronze (CuSn12Ni2) worm wheels, our NMRV reducers deliver smooth, silent torque multiplication and space-saving right-angle hollow shaft mounting.

Product Lineup

Equipment & Range Highlights

NMRV Series • Size 025 to 150

NMRV Right-Angle Worm Speed Reducers

Universal mounting worm gearboxes with standard hollow output shafts, torque arms, output flanges, and single/double solid output shafts.

SizesNMRV 025, 030, 040, 050, 063, 075, 090, 110, 130, 150

Ratiosi = 5, 7.5, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100:1

TorqueUp to 2,200 Nm

Combined PC-NMRV • Ultra Slow Speed

Pre-Stage Helical & Double-Worm Reducers

Combined PC helical pre-stage and double worm units achieving high reduction ratios up to i = 5000:1 for ultra-slow mixing and indexing drives.

Ratiosi = 100:1 up to 5000:1

Speeds0.3 RPM to 14 RPM

TorqueHigh Multiplication

NMRV Sizing Specs

NMRV Worm Gearbox Selection Reference

NMRV Size	Max Input Motor Power (kW)	Max Output Torque (Nm)	Hollow Shaft Bore Diameter (mm)
NMRV 030	0.18 kW (0.25 HP)	21 Nm	14 mm Keyway
NMRV 040	0.37 kW (0.50 HP)	45 Nm	18 mm Keyway
NMRV 050	0.75 kW (1.0 HP)	88 Nm	25 mm Keyway
NMRV 063	1.50 kW (2.0 HP)	175 Nm	25 mm / 28 mm Keyway
NMRV 075	4.00 kW (5.5 HP)	300 Nm	28 mm / 35 mm Keyway
NMRV 090	4.00 kW (5.5 HP)	480 Nm	35 mm Keyway
NMRV 110	7.50 kW (10.0 HP)	850 Nm	42 mm Keyway
NMRV 130	7.50 kW (10.0 HP)	1,350 Nm	45 mm Keyway
NMRV 150	15.0 kW (20.0 HP)	2,200 Nm	50 mm Keyway

Key Features

Engineering & Build Highlights

Right-angle 90° orientation saves critical space alongside machines and conveyor side frames
Hollow output shaft mounts directly onto the driven machine shaft with a simple torque arm, eliminating couplings
Irreversible self-locking capability (on ratios ≥ 40:1) prevents loads from rolling backward when power is switched off
Phosphor bronze worm wheel (CuSn12) offers low friction coefficient and superior wear resistance
Pre-filled with synthetic lubricant (PAG ISO VG 320) for maintenance-free lifetime lubrication
Universal cube design with threaded mounting holes on all six surfaces for flexible orientation

Applications

Target Applications & Sectors

Food packaging, bottling & sorting belt conveyorsRotary feeding valves & screw auger conveyorsBakery dough kneaders, mixers & commercial ovensCar wash conveyors & automated toll barrier gatesSolar tracking actuator drives & motorized solar louvresTextile machinery & printing press roller drives

FAQs

On ratios i ≥ 40:1, the lead angle of the worm thread is smaller than the friction angle. This creates static self-locking, meaning the driven machine shaft cannot back-drive the motor, providing built-in mechanical holding without needing a brake motor.

Yes. NMRV gearboxes can be mounted in any orientation (B3, B6, B7, B8, V5, V6). For vertical mounting (V5/V6), ensure synthetic oil fill levels are adequate to lubricate the top bearing.

Worm Geared Motors (NMRV)