WEG Reversing Starter Assembly MPW-40 + 2×CWM25 (up to 2.2 kW)

The WEG Reversing Starter Assembly combining MPW-40 motor protection circuit breaker with two CWM25 contactors (mechanically and electrically interlocked) provides a complete, IEC 60947-4-1 coordinated reversing motor starter for three-phase motors up to 2.2 kW at 400 V AC. Reversing starters are essential in Saudi industrial applications involving bi-directional conveyors, damper and valve actuators, bridge crane end-stop drives, and positioning systems used in oil and gas, petrochemical, and materials handling facilities.

Reversing Starter Design

A reversing starter uses two contactors: one for forward rotation (F-contactor, CWM25-F) and one for reverse rotation (R-contactor, CWM25-R). Mechanical interlock prevents both contactors from closing simultaneously, and electrical interlock via NC auxiliary contacts ensures the same. The MPW-40-3-D040 MPCB provides common overload and short-circuit protection for both directions of rotation. The control circuit includes separate FORWARD and REVERSE pushbuttons with an STOP button, and optionally a mechanical cam-operated interlocking device for positive interlock assurance in safety-critical Saudi process plants.

IEC 60947-4-1 Coordination

Type 2 coordination is confirmed for the reversing assembly at 100 kA at 400 V, providing the same no-damage assurance under short-circuit conditions as the DOL assembly. Under reverse-plugging conditions (changing direction without stopping), the contactor contacts are subjected to higher electrical stress. WEG's coordination data for reversing starters using CWM25 confirms this is within the rated duty cycle for the contactor, provided the control circuit includes a minimum 0.5 second delay between direction changes — a feature included in Razz Middle East's pre-wired reversing starter control circuit design.

Saudi Applications

Reversing motor starters are found in Saudi petrochemical plants for valve actuator controls, in warehouse automation for reversible conveyor systems, in water treatment facilities for clarifier rake drives, and in oil and gas offshore platforms for crane and winch positioning systems. Razz Middle East supplies pre-wired reversing starter assemblies with all interlocking pre-tested and documented, reducing EPC installation time and inspection effort on large Saudi projects.