Cam switch 0-star-delta 3P 40A Elektromet Łuk 40-21 (924009)

Electromet Łuk 40-21 cam switch configured for 0–star–delta (0–star–triangle) motor switching. This three-pole 40 A cam (rotary) switch is intended for changing the connection of three-phase motors between star and delta configurations or for selecting an off/0 position. It is suitable for mounting in motor control panels, motor starters and industrial machinery where a compact mechanical solution for manual or automatic changeover is required.

Advantages

The cam switch provides a robust mechanical switching mechanism designed for frequent operation and clear tactile feedback. Its three-pole construction supports standard three-phase motor wiring and the 40 A rating accommodates a range of small to medium power motors. The 0 position allows safe isolation or a neutral setting between star and delta arrangements, simplifying commissioning and maintenance tasks.

Suitable for

• Manual or semi-automatic motor starters in industrial environments
• Applications requiring star–delta (Y–Δ) changeover for three-phase motors
• Control panels where a dedicated off/0 position is needed between switching states
• Machinery with straightforward mechanical switching requirements and limited space

When it may not be suitable

This cam switch is a mechanical device and may not be appropriate where fully electronic or soft-start motor control is required, such as variable frequency drives (VFDs) or electronic soft starters that provide smoother torque and adjustable ramp profiles. It also may not suit installations that demand higher continuous current ratings than 40 A or where contactor-based interlocking and remote motor protection are mandatory.

Key specifications

• Poles: 3-pole (three-phase)
• Rated current: 40 A
• Switching configuration: 0–star–delta (0–Y–Δ)
• Actuation: cam (rotary) mechanical switch
• Intended use: motor connection changeover (star/delta) and off/0 position
• Mounting: panel/machine mounting suitable for control panels and starters

How to use

Install the cam switch in an appropriate cut-out in the control panel or starter enclosure following applicable electrical standards and safety practices. Wire the three incoming and three outgoing phase conductors to the corresponding terminals according to the motor wiring diagram: one set for star, one for delta and the neutral/off connections for the 0 position. Ensure proper torque on terminal screws and provide overload protection, interlocks or auxiliary contacts externally if required. Operate the rotary handle to select 0, star or delta positions only when the motor is stopped or under conditions allowed by the control scheme to avoid mechanical stress and electrical arcing.

What to consider before purchase

• Verify that a 40 A rated mechanical switch meets the motor's starting and running current requirements
• Confirm that a mechanical star–delta changeover is compatible with your control strategy and protection devices
• Check available panel space and mounting cut-out dimensions to ensure fitment
• Determine whether additional contactors, timers or interlocks are needed for safe and automated operation

Usage recommendations

Use the cam switch as part of a complete motor control arrangement: include proper overload protection, correctly rated fuses or breakers, and mechanical interlocks where necessary. For frequent switching or precise motor control, evaluate electronic alternatives. Regularly inspect terminals and contacts for tightness and signs of wear, and perform switching operations according to the machine’s safety procedures.