RH Series
RH Series Helical Gearboxes
In-line helical reduction built for continuous industrial duty.
Two and three stage in-line helical gearboxes in cast iron housings. Case-hardened, profile-ground helical gearing gives high efficiency and low noise on drives that run around the clock.

- Power range
- 0.37 kW to 30 kW
- Ratio range
- 10:1 up to 100:1
- Frame sizes
- RH 27 to RH 137
- Efficiency
- Up to 97 percent
Built for Duty
What separates RH Series from a general-purpose drive.
Profile-ground helical gearing
Ground tooth flanks spread load along the helix, so the unit runs quieter and holds its rating over long service.
Cast iron housing
Rigid one-piece body keeps shaft alignment under shock load and adds mass that damps drive noise.
High efficiency per stage
Around 97 percent per stage means less input power wasted as heat than an equivalent worm drive.
Oversized bearings
Bearings selected for radial and axial overhung load so belt and chain drives can be coupled directly.
Modular to geared motor
The same gear case takes an IEC adapter or a close-coupled motor, sharing spares with the RG Series.
Selection data
Technical Specifications
RH Series — frame size against power, output shaft and ratio
| Model | Power range | Output shaft | Ratio range |
|---|---|---|---|
| RH 27 | 0.37 kW | 25 mm | 10:1 to 100:1 |
| RH 37 | 0.37 / 0.75 kW | 25 mm | 10:1 to 100:1 |
| RH 47 | 0.75 / 1.1 / 1.5 kW | 30 mm | 10:1 to 100:1 |
| RH 57 | 2.2 / 3.7 kW | 35 mm | 10:1 to 100:1 |
| RH 67 | 2.2 / 3.7 kW | 35 mm | 10:1 to 100:1 |
| RH 77 | 2.2 / 3.7 / 5.5 / 7.4 kW | 40 mm | 10:1 to 100:1 |
| RH 87 | 3.7 / 5.5 / 7.4 / 11 / 15 kW | 50 mm | 10:1 to 100:1 |
| RH 97 | 5.5 / 7.4 / 11 / 15 / 18.6 / 22 kW | 60 mm | 10:1 to 100:1 |
| RH 107 | 11 / 15 / 18.6 / 22 kW | 70 mm | 10:1 to 100:1 |
| RH 137 | 15 / 18.6 / 22 / 30 kW | 90 mm | 10:1 to 100:1 |
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 RH Series Runs
- Cement and aggregate plants
- Shot blasting machines
- Water treatment plants
- Rolling mill auxiliaries
- Bucket elevators
- Crushers and pulverisers
Also consider
Related Products
Quote the RH Series
Send the power, input speed, required output speed and the driven machine. We will confirm the frame, ratio and mounting, and price it.


