Sprint Electric SL Series DC Drives
Analogue three-phase 2Q DC drives for precise, dependable DC motor control
The Sprint Electric SL Series DC Drives provide a compact and economical solution for controlling industrial DC motors where dependable analogue control, controlled acceleration, and stable speed regulation are required. Designed by Sprint Electric for demanding industrial applications, the SL range combines three-phase thyristor technology with analogue control circuits across a broad range of motor power ratings.
Industrial Motor Warehouse supplies the complete SL range, covering 5 kW to 145 kW and output currents from 12 A to 330 A. The range includes 11 models, making it practical to select a drive closely matched to the motor’s armature current and power requirements.
Why Choose the Sprint Electric SL Series?
The Sprint Electric SL drive is engineered for applications that still rely on conventional DC motors but need modern, reliable electronic speed control. Unlike a simple fixed-voltage DC supply, a controlled DC drive regulates the motor’s armature voltage and current to provide controlled acceleration, speed regulation, and torque response.
The SL range uses a three-phase, two-quadrant configuration. Two-quadrant operation allows the motor to operate in forward and reverse torque conditions while maintaining a single direction of rotation, making the technology suitable for applications where controlled braking is required but full regenerative four-quadrant operation is unnecessary.
The range is particularly relevant for OEM equipment, machinery upgrades, and replacement projects where analogue control architecture is preferred. Sprint Electric describes the SL family as an economical, compact, and reliable platform for users requiring analogue loop controls.
SL Series Technical Range
Industrial Motor Warehouse currently has 11 SL models:
| Model | Motor Power | Output Current | Configuration |
|---|---|---|---|
| SL5 | 5 kW | 12 A | 2Q, three phase |
| SL10 | 10 kW | 24 A | 2Q, three phase |
| SL15 | 15 kW | 36 A | 2Q, three phase |
| SL20 | 20 kW | 48 A | 2Q, three phase |
| SL30 | 30 kW | 72 A | 2Q, three phase |
| SL40 | 40 kW | 96 A | 2Q, three phase |
| SL50 | 50 kW | 120 A | 2Q, three phase |
| SL65 | 65 kW | 155 A | 2Q, three phase |
| SL85 | 85 kW | 205 A | 2Q, three phase |
| SL115 | 115 kW | 270 A | 2Q, three phase |
| SL145 | 145 kW | 330 A | 2Q, three phase |
These ratings demonstrate the scalability of the platform, from relatively small 5 kW DC motors through to high-power 145 kW industrial machines.
Analogue DC Drives for Industrial Motor Control
One of the defining characteristics of the SL platform is its analogue control architecture. Analogue DC drives remain valuable in applications where established analogue reference signals, feedback devices, and machine-control systems are already installed.
For retrofit projects, replacing an obsolete controller with an analogue-compatible drive can reduce the need for extensive changes to the existing control system. Depending on the application, speed feedback can be derived from tachogenerator or armature-voltage feedback arrangements. Sprint Electric documentation identifies selectable tachogenerator or armature-voltage feedback and other configurable control functions within the SL family.
This makes the SL series particularly useful when engineers need to modernise the power-control section of an existing machine without completely redesigning its automation architecture.
Three-Phase 2Q DC Drive Technology
The SL series belongs to the three phase DC drives category, using a three-phase controlled rectifier to supply DC motor armature.
Three-phase conversion offers several engineering advantages over single-phase conversion for higher-power DC motor applications. It provides a more frequent sequence of controlled power pulses, helping deliver smoother armature current and making three-phase conversion well suited to industrial motors at higher power ratings.
The 2Q technology is important when selecting a drive. A two-quadrant drive permits motoring and braking torque in one direction of rotation. It should therefore not be confused with a four-quadrant regenerative drive, which provides controlled operation in both rotational directions.
For applications requiring full forward/reverse regenerative operation, Sprint Electric’s SLX range is the more appropriate technology because it provides four-quadrant operation.
Key Technical Features
The Sprint Electric SL platform offers features intended to simplify integration into industrial control systems, including:
- Analogue control loops for conventional machine-control architectures
- Three-phase thyristor power conversion
- Two-quadrant DC motor operation
- Armature-voltage and tachogenerator feedback options
- Field weakening capability on applicable SL/SLX configurations
- Configurable inputs and outputs for machine integration
- S-ramp functionality for controlled acceleration and deceleration
- Current and speed control suitable for industrial DC motor applications
Typical Applications
Sprint Electric DC drives are suited to industrial equipment where DC motors continue to provide advantages in torque control, speed regulation, or existing machine compatibility.
Typical applications include:
- Conveyors and material-handling machinery
- Printing and paper-processing equipment
- Extrusion and process machinery
- Machine tools
- Winding and unwinding systems
- Industrial production lines
- Retrofit and replacement installations
- OEM machinery incorporating DC motors
The correct drive should always be selected against the motor’s rated armature voltage, armature current, field requirements, feedback method, duty cycle, and required braking behaviour rather than simply matching the kW rating.
SL vs SLX vs SLEL: Which Drive Do You Need?
Choosing between Sprint Electric ranges depends primarily on the required operating quadrants and control architecture.
| Requirement | SL | SLX | SLE |
|---|---|---|---|
| Control Type | Analogue | Analogue | Analogue |
| Quadrants | 2Q | 4Q | 2Q |
| Regenerative Quadrant | Limited to 2Q braking characteristics | Full regenerative | 2Q |
| Power range | 5-145 kW | 5-145 kW | 14-44 kW |
| Best Suited to | Single-direction industrial DC applications | Reversing/regenerative applications | Economical single-direction applications |
The SL Series is therefore a strong choice where analogue three-phase 2Q control is required. Where full regenerative four-quadrant operation is essential, the SLX range should be considered. For cost-sensitive applications within its narrower rating range, the SLE provides an alternative 2Q platform.
Selecting the Correct Sprint Electric SL Drive
Correct sizing needs more than comparing motor nameplate kW. Engineers should check:
- Motor armature current - The drive’s continuous output-current rating must be suitable for the motor.
- Armature voltage - Confirm that the drive’s output capability matches the DC motor.
- Field current - Verify field supply requirements and whether field weakening is required.
- Feedback type - Establish whether armature-voltage or tachogenerator feedback is required.
- Duty cycle - Consider continuous, intermittent, and overload operating conditions.
- Braking requirements - Determine whether 2Q operation is sufficient or whether four-quadrant regeneration is necessary.
- Control interface - Confirm compatibility with the existing analogue reference and machine-control system.
For replacement projects, comparing the existing drive’s model, motor nameplate data, feedback arrangement, and application requirements is the safest way to establish a suitable replacement.
Buy Sprint Electric SL Drives from Industrial Motor Warehouse
Industrial Motor Warehouse offers the Sprint Electric SL Series DC Drives for UK industrial applications, with models spanning 5 kW to 145 kW and 12 A to 330 A. The range provides engineers, OEMs, and maintenance teams with a practical solution for new installations, machinery upgrades, and obsolete DC drive replacements.
If you are replacing an existing DC controller, selecting a drive for a new machine, or need help matching an SL model to a motor, review the motor nameplate and drive requirements before placing an order. Contact Industrial Motor Warehouse for technical assistance in selecting the correct Sprint Electric SL drive for your applications.