- Product Spotlight
How to Choose Between a Schneider Drive, Soft Starter, or Across-the-Line Starter
- By Emily Hagel
Motor control equipment has a significant impact on system performance, energy use, and long-term reliability. Schneider Electric offers several solutions for starting and controlling motors, including variable frequency drives (VFDs), soft starters, and across-the-line starters. While each technology serves a different purpose, selecting the right option depends on application requirements, operating environment, and cost considerations.
Understanding the functional differences between these solutions can help facilities choose the most efficient, reliable, and cost-effective option for their operation.
Across-the-Line Starters
Across-the-line starters, also known as direct-on-line (DOL) starters, apply full voltage to the motor the moment the system energizes. This method is simple, cost-effective, and commonly used in industrial environments.
However, the abrupt nature of the start creates high inrush current and mechanical stress that can place wear on belts, bearings, gearboxes, and other connected equipment. Because there is no ramping, control, or monitoring available, across-the-line starters are typically used in smaller or non-critical applications where motors can tolerate the stress and where advanced performance control is not required.
Benefits
- Low initial cost
- Simple installation and maintenance
- Widely available and easy to replace
- Suitable for small or non-critical motors
Considerations
- High inrush current at startup
- Increased mechanical and electrical stress
- Limited control over starting torque or speed
- Higher long-term wear on system components
Schneider Soft Starters
Soft starters offer a middle ground between basic starters and advanced drive systems. Instead of applying full voltage immediately, they gradually ramp voltage, producing a smoother acceleration. This controlled start reduces electrical and mechanical stress, helping extend the lifespan of connected components. It can also prevent issues such as belt slippage, pressure spikes, and nuisance trips.
Soft starters are often used when a motor operates at a constant speed but experiences strain during startup. They are common in pump, fan, and conveyor applications where the goal is to minimize wear and prevent system disruption, rather than dynamically control speed or torque. While soft starters improve startup performance, they do not provide speed regulation during normal operation, meaning energy savings and system flexibility are limited compared to a VFD.
Benefits
- Reduced inrush current
- Smooth acceleration and deceleration
- Lower mechanical wear on equipment
- Enhanced protection against line disturbances
Considerations
- Fixed-speed operation once running
- Limited energy savings during normal operation
- Less control than a variable frequency drive
Schneider Variable Frequency Drives
Variable frequency drives, including Schneider Electric’s Altivar line, take motor control a step further by regulating speed, torque, and power consumption throughout the operating cycle. Rather than simply smoothing startup, a VFD continuously adjusts motor output based on system demand.
This capability often results in lower energy use, reduced mechanical wear, and greater consistency in production processes. A VFD can also identify fault conditions, monitor system performance, and support predictive maintenance strategies, helping reduce unplanned downtime.
Drives are commonly used in applications that require variable speed, precise control, or measurable energy reduction, such as material handling systems, HVAC equipment, and pumps with fluctuating flow requirements. While drives have a higher upfront cost and require more configuration, the long-term savings and performance gains can outweigh the initial investment—especially in energy-intensive environments.
Benefits
- Adjustable speed control
- Significant energy savings
- Reduced mechanical stress and wear
- Built-in diagnostics and fault monitoring
- Improved process consistency and uptime
Considerations
- Higher initial cost than soft starters or DOL
- Additional programming and setup may be required
- Not necessary for fixed-speed applications
How to Select the Best Option
Choosing between a Schneider drive, soft starter, or across-the-line starter depends on system needs, performance goals, and budget.
When an Across-the-Line Starter Is Suitable
- Small motors with infrequent starts
- Simple, fixed-speed applications
- Low sensitivity to wear or downtime
- Budget-constrained environments
When a Soft Starter Is the Best Fit
- Systems with high mechanical stress at startup
- Minimal need for speed control
- Limited electrical infrastructure capacity
- Moderate cost requirements
When a Schneider Drive Is Preferred
- Variable load or speed conditions
- Need for precise control or automation
- Energy efficiency or sustainability goals
- High uptime or reliability expectations
Cost and Lifecycle Considerations
Initial equipment cost is only one factor in total system expense.
- Across-the-line starters have the lowest upfront cost but may increase long-term maintenance.
- Soft starters offer moderate cost with improved reliability.
- VFDs have higher initial cost but can significantly reduce operating expenses and downtime.
Facilities with high energy consumption or frequent system cycling often see the greatest return with a drive-based solution.
Maintenance and Operational Reliability
Motor control strategies influence maintenance programs in different ways. Direct-on-line starters can accelerate wear due to abrupt acceleration, while soft starters reduce startup strain but do not offer ongoing monitoring. Drives minimize mechanical stress and provide real-time performance data that can support predictive maintenance efforts, allowing teams to identify issues before they cause downtime.
Facilities that are highly sensitive to interruptions often benefit from the added control, visibility, and protection associated with drives.
Where to Find Schneider Products Through Lakeland Engineering
Schneider Electric motor control products are stocked and supported at Lakeland Engineering’s Minneapolis and Kansas City branches. Our teams at these locations can help with equipment selection, upgrades, and identifying the best solution for your application.
Share the Post:
