Bulk material handling plants rely heavily on electric motors to drive conveyors, crushers, mills, pumps and fans across ports, quarries, cement plants and mineral processing facilities. In many of these installations, motors start under load and operate in demanding conditions where reliability and mechanical stability are critical.
“In bulk handling systems, motors frequently start under load and often drive high-inertia equipment such as conveyors or crushers,” TECO Australia & New Zealand product manager – drives and automation Hamish Robertson said. “How the motor starts and stops has a direct influence on drivetrain stress and long-term equipment reliability.”
In many plants, motors are still started using direct-on-line ( DOL ) methods. When a motor starts this way, full voltage is applied instantly, producing high inrush current and a rapid rise in torque. For high-inertia equipment such as crushers or long conveyors, this sudden torque transfer can introduce shock loading into belts, couplings, gearboxes and other drivetrain components.
Soft starters address this by controlling the voltage applied to the motor during startup, allowing current and torque to increase progressively rather than instantaneously. The result is smoother acceleration of the driven equipment which reduces electrical and mechanical stress.
To address different industrial applications, TECO structures its soft starter product range across multiple solution levels.
The TECO RSXi soft starter range is designed for motors from 18 A to 200 A operating at supply voltages up to 575 VAC. The unit uses a compact closed-loop control architecture with two-phase control and internal bypass, allowing the motor to run with minimal heat dissipation once it reaches full speed. Adjustable current ramp and current limit functions allow the start profile to be tuned to the application, while integrated protection functions include motor overload protection, phase sequence protection, current imbalance protection and excess start-time protection.
This type of solution is typically used where a controlled start is required but system complexity must remain low, such as pump stations, smaller conveyors or compressor installations.
For larger motors and more demanding industrial systems, the TECO TSXi soft starter range supports currents from 24 A up to 1250 A and operates at supply voltages up to 690 VAC. The platform uses full three-phase SCR control and provides multiple configurable start methods including constant current, current ramp and adaptive control.
Stopping behaviour can also be configured using adaptive stop, soft brake or DC brake functions, allowing the deceleration profile to be matched to the behaviour of the driven equipment. This is particularly relevant in conveyors and crushers where controlled stopping can influence system stability and mechanical load behaviour.
The TECO TSXi platform also provides event logging, integrated metering and communication expansion modules, enabling integration with PLC and SCADA systems for monitoring and diagnostics.
“In applications such as conveyors or crushers, controlling both acceleration and deceleration can significantly improve how the mechanical system behaves,” Robertson said. “Being able to adjust the start and stop profile allows the motor control system to respond more effectively to the load.”
In large bulk handling plants, particularly those operating heavy conveyors, crushers or grinding mills, motor supply voltages and power levels can exceed the limits of standard low-voltage motor control equipment. For these installations, TECO offers the TECO TSXi-1200V soft starter, designed for motors operating at 1000 VAC with current ratings from 202 A to 1092 A.
This solution is designed for engineered motor control systems and requires external bypass and switching devices within the switchboard architecture. Typical applications include large pumps, crushers, mills, heavy conveyors and high-power compressors & Ventilation Fans, where motors drive equipment subject to significant mechanical loads and electrical constraints.
As bulk handling systems continue to increase in scale and throughput, managing how motors start and stop becomes increasingly important for both electrical and mechanical system performance. An industry where equipment failure and unplanned downtime needs to be reduced to meet customer demands. Controlled motor starting allows operators to reduce drivetrain stress, improve equipment behaviour during startup and support more reliable plant operation.