Power Electronics Smooth-Move — AC Soft-Start Motor Control for Single-Speed and Two-Speed Crane and Industrial Applications
Power Electronics Smooth-Move is a compact AC soft-start motor control engineered for single-speed and two-speed three-phase AC motor applications in overhead crane bridge and trolley travel, monorail, conveyor, and general industrial equipment where the mechanical shock, drive train stress, and contactor wear caused by across-the-line motor starting are the primary maintenance and reliability concerns. Smooth-Move is not a variable frequency drive — it does not provide variable speed control or controlled deceleration. Its specific function is to phase in motor voltage gradually at startup, softly bringing the motor to full voltage over an adjustable time and torque ramp rather than applying full line voltage instantaneously — eliminating the inrush current spike and mechanical shock that across-the-line starting delivers to gearing, belts, couplings, and drive train components on every motor start cycle.
Smooth-Move 1 and Smooth-Move 2
Smooth-Move is available in two models. Smooth-Move 1 serves single-speed motor applications — phasing in voltage at startup to eliminate the mechanical shock, gear damage, belt wear, and drive train stress that across-the-line motor starting causes in crane travel applications, with Arc-Elimination on contactors extending contactor service life in high-cycle US crane installations. Smooth-Move 2 serves two-speed motors — providing smooth transitional torque control between high and low speed that prevents the mechanical stress of abrupt speed transitions on two-speed crane bridge, trolley, and conveyor drive systems. Both models operate on 208-480V three-phase supply across standard US industrial voltages, with 575V configurations also available for Canadian and US facilities operating at 575V supply. Operating temperature range is -10°C to 55°C (14°F to 131°F) — installations in proximity to radiant heat sources require shielding to maintain safe operating temperature. Both models are (c)UL listed and manufactured in the USA.
Smooth-Move 1 — Single-Speed Soft-Start Control
Smooth-Move 1 is engineered for single-speed three-phase AC motor applications — crane bridge and trolley travel, monorail, conveyor, and general industrial equipment operating on a single motor speed. Smooth-Move 1 softly phases in motor voltage from an adjustable initial starting torque level to full line voltage over an adjustable time ramp — eliminating instantaneous inrush current and the mechanical shock that damages gearing, breaks belts, and accelerates wear on drive train components in single-speed crane and industrial motor applications. Available for motors up to 10 full load amps — approximately 5HP at 460VAC — with automatic universal VAC selection covering 200, 208, 240, 385, 415, 440, and 480VAC in a single unit, with 200 through 575VAC also available. Smooth-Move 1 also incorporates Arc-Elimination on contactor make and break, extending contactor mechanical life to its maximum limit and reducing the cost and frequency of contactor replacement in high-cycle crane and industrial applications.
Smooth-Move 2 — Two-Speed Transitional Soft-Start Control
Smooth-Move 2 is engineered for two-speed three-phase AC motor applications — crane bridge and trolley travel systems using two-winding or consequent-pole two-speed motors where smooth transitional control between high and low speed is as important as smooth starting. Standard two-speed motor control produces a harsh mechanical jerk during high-to-low and low-to-high speed transitions that stresses drive components and disrupts crane operation. Smooth-Move 2 manages all motor transitions electronically — smooth starting from stop to low speed, smooth acceleration from low speed to high speed, and smooth high-to-low speed transition — without timers and without the mechanical shock that standard two-speed contactor control produces on every speed transition. Available for motors up to 8 full load amps, approximately 5HP at 480VAC, with the same automatic universal VAC selection as Smooth-Move 1. Arc-Elimination has been incorporated into both forward-reverse and high-low contactors, enhancing the lifespan of the contactors at every switching point within the two-speed control circuit.
When to Specify Smooth-Move vs. a Full VFD
Smooth-Move is the correct specification when the top requirement is eliminating mechanical shock at motor startup and speed transitions in a single or two-speed application, and when variable speed control, controlled deceleration, and programmable speed profiles are not required. For applications needing variable speed control, accurate stopping, multi-speed functions, or sophisticated crane control like anti-sway, the recommended Power Electronics options are Micro-Speed Smart-Move, CX, MX-Ultra, or MV-Ultra. Crane-Controls.com's technical team can assist US buyers in determining whether Smooth-Move soft-start control or a full Micro-Speed VFD is the correct solution for their specific crane or industrial motor control application.
Crane-Controls.com offers Power Electronics Smooth-Move 1 and Smooth-Move 2 controls across the standard FLA and voltage range for US crane and industrial applications. Both models are UL listed and C-UL listed for all Canadian provinces, manufactured in the USA at PE's East Dundee, Illinois facility. OSHA and ASME B30 compliant installations supported.
