Worm Gearbox Products

Worm Gearboxes for Australian Industry — Complete Product Guide

Ever-Power manufactures four series of worm gearboxes and worm gear reducers from our integrated facility, supplying direct to engineers, OEM machinery builders, and procurement teams across Australia, the United Kingdom, North America, and Southeast Asia. All products are ISO 9001 certified and CE marked, with full export documentation prepared as standard.

NMRV Worm Gearbox — The Industry Standard

The NMRV series is the most widely specified worm gearbox in Australian industry. Its aluminium alloy housing delivers excellent thermal conductivity — critical for dissipating the frictional heat generated in the worm mesh — combined with low weight and corrosion resistance suited to food processing, agricultural, and outdoor industrial environments. The IEC B14 and B5 flange configurations are fully compatible with Australian 400 V / 50 Hz motors without modification.

Frame sizes run from NMRV025 through NMRV130, covering input powers from 0.06 kW to over 9 kW and output weights from 0.7 kg to 48 kg. The compact footprint of the smaller frames (NMRV025 through NMRV063) makes them a practical choice for multi-drive conveyor layouts where multiple gearboxes are installed in close proximity.

NRV Shaft-Mount Worm Reducer — Where Baseplate Mounting Is Not Practical

The NRV series uses the same worm gear internal geometry as the NMRV but is housed and configured for shaft-mount installation. A hollow bore output accepts the driven shaft directly, and the gearbox is retained against rotation by a torque arm attached to the machine structure. This arrangement eliminates the need for a separate motor support pedestal and a coupling between the gearbox output shaft and the driven shaft — reducing total drivetrain length and simplifying installation on conveyor tail shafts, agitator drives, and similar applications.

Double-Stage Worm Gearboxes — High Ratio in a Single Housing

When a single worm stage cannot provide sufficient gear reduction, a double-stage combination extends the available ratio range to 150:1 and above — with some NMRV combinations achieving ratios of 3,000:1 to 5,000:1. Double-stage units consist of two NMRV worm stages coupled in series within a common mounting arrangement. The output of the first (high-speed) stage drives the input of the second (low-speed) stage, multiplying the gear ratio while retaining the self-locking characteristic of worm gearing. Our applications page includes worked examples of double-stage selection for agitator and gate actuator installations.

PC+NMRV Helical-Worm — Efficiency Where It Matters

The PC+NMRV series addresses the principal limitation of standard worm gearboxes: efficiency. A worm mesh typically achieves 60–80% efficiency at moderate ratios, generating heat that limits continuous duty rating and increases operating costs. The PC+NMRV helical pre-stage achieves above 95% efficiency in the first reduction step, delivering torque to the NMRV worm output stage at a significantly lower speed than the motor input. The result is a combined efficiency meaningfully higher than a double-stage worm-only unit at comparable overall ratios, with the same right-angle output and self-locking behaviour retained by the worm output stage.

PC frame sizes PC063, PC071, PC080, and PC090 are each matched to compatible NMRV output stages, covering a wide matrix of overall gear ratios and output torque ratings. For servo and stepper motor applications, the helical stage's higher torsional stiffness and lower backlash compared to a worm input stage is an additional benefit.