English
Français
Türkçe
Español
Русский
The motor delivers the same torque in both drives, but the load on the shaft differs.
| Criterion | Direct coupling drive | Belt-and-pulley drive |
|---|---|---|
| Speed | Machine speed equals motor speed | Can be changed with the pulley ratio |
| Load on shaft | Mainly torque; small side load with good alignment | Continuous radial load from belt tension |
| Critical check | Offset, angular alignment, matching shaft height | Pulley diameter, pulley position on the shaft, belt tension |
| Bearing | Standard bearing arrangement is usually enough | The drive-end bearing is stressed more |
| Mounting | Fixed base, little adjustment | Tensioning rails or a slide base are needed |
With a coupling, the new motor's shaft height must match the old one; otherwise shims are needed and alignment becomes harder. With a belt drive, the force on the shaft end matters as much as motor power: a small motor pulley and an over-tensioned belt shorten bearing life.
For heavy belt drives (crushers, mills, large fans), state the pulley diameter and belt type when ordering; the permissible shaft load is confirmed for the model. Speed matching examples are in our 110 kW speed and drive matching article.