Direct Drive Systems for Pulp & Paper Mills
Permanent magnet direct drive for the equipment that carries a mill's continuous duty — conveyors, drum pulpers, refiners, screens, stock pumps, vacuum systems and cooling tower fans — with site assessment, integration and commissioning support.
Where drives carry the load in a mill
Papermaking is a continuous process: pulping, stock preparation, screening and the approach flow system all depend on rotating equipment that runs between planned outages. Drive selection in these stages is an availability decision as much as an efficiency decision.
- 01
Material handling
Logs, chips, recovered paper and solid waste move on belt conveyors between process stages — continuous duty, often in wet and fibre-laden air.
- 02
Pulping
Drum pulpers and auxiliary equipment break down recovered paper and fibre feedstock. High starting torque and variable load define the drive requirement.
- 03
Stock preparation
Refiners, deflakers, mixers and agitators condition the stock. These machines run for long campaigns at steady, torque-dominated duty.
- 04
Screening & cleaning
Pressure screens, separators and purification equipment remove contaminants before the stock reaches the approach flow system.
- 05
Approach flow & machine auxiliaries
Stock pumps, fan pumps, vacuum systems and cooling tower fans support the paper machine — a large population of motors running near-continuously.
Where permanent magnet direct drive is applied
A permanent magnet motor wound for the driven speed removes the reducer, high-speed coupling and its lubrication system from the drivetrain. In a mill that matters most where duty is continuous, torque rather than speed defines the machine, and the drive is difficult or costly to service. It is an application decision, not a blanket replacement for every geared drive on site.
What a mill drive evaluation requires
An assessment starts from the machine and its duty, not from a catalogue. The following information is what we ask for before stating whether a direct drive conversion is technically and commercially appropriate.
- Equipment type
- Conveyor, drum pulper, refiner, mixer, screen, pump, fan or vacuum system, with the machine's role in the process.
- Duty data
- Operating hours, load profile, throughput and any seasonal or campaign variation.
- Torque and speed
- Rated and operating speed, starting or breakaway torque requirement, and absorbed power where measured.
- Existing drivetrain
- Motor nameplate data, gearbox ratio and service factor, coupling arrangement, lubrication and maintenance history.
- Mechanical envelope
- Available space at the drive, shaft and foundation arrangement, and crane or access limits.
- Electrical supply
- Service voltage, available capacity, starting method in use and whether an existing VFD would be retained.
- Environment
- Ambient temperature, moisture and fibre loading, washdown exposure and any hazardous-area classification.
- Shutdown windows
- Planned outage schedule and the installation window available for a conversion.
Representative drive data
Values below are representative datasheet figures for the permanent magnet drive equipment classes used in pulp and paper applications. Final selection is confirmed against the machine duty during engineering assessment.
Full motor family parameter ranges — line-start, variable-speed, low-speed direct drive and motorized pulley — are consolidated in the motor selection reference.
| 01Motor type | Three-phase permanent magnet synchronous |
|---|---|
| 02Starting / control | Self-starting or variable-frequency drive |
| 03Rated voltage | 380 V / 660 V, three-phase, 50 HzMedium-voltage (e.g. 6 kV) designs available by selection. |
| 04Rated efficiency | ≥ 96%Representative models 94.7–96.0% and above, per datasheet. |
| 05Power factor | ≥ 0.96 |
| 06Momentary overload | 2 × ratedVariable-speed designs; suitable for heavy-load starting. |
| 01Arrangement | Motorized pulley — motor inside the drum |
|---|---|
| 02Drivetrain removed | External motor, gearbox, coupling, foundation |
| 03Representative drum diameters | 800 – 1400mm |
| 04Control | VFD speed regulation; multi-drive power balance |
| 05Starting | Soft start, controlled torque, no impact current |
| 06Noise | < 70dB(A)Manufacturer datasheet value for pulley installations. |
Assess a drive application in your mill
Send us the equipment, duty data and existing drivetrain arrangement. We will tell you whether direct drive is suitable, what the conversion involves, and what information is still missing.