Bistable Switch KCB-A KCB-B MKG131-03

KCB-A, KCB-B, and MKG131-03 are commonly used in elevator control and maintenance switching systems.

Unlike standard momentary switches, bistable switches are designed to maintain switching status after activation until the next operation cycle.

These models are generally associated with:

• maintenance control circuits
• safety switching systems
• inspection operation panels
• mechanical holding control

Usually installed inside maintenance panels or elevator control assemblies.

Common Field Situation

In some older elevator systems in Argentina and Thailand, bistable switch problems may gradually appear after long-term operation because of:

• internal contact wear
• unstable holding response
• mechanical fatigue
• oxidation inside the switch assembly

Typical field symptoms may include:

• switch status not holding correctly
• intermittent inspection response
• unstable maintenance mode activation
• abnormal control reset behavior

During troubleshooting work, technicians sometimes inspect both the switch and terminal wiring together.

Difference Between Bistable and Standard Switches

Compared with ordinary push switches, bistable switches are mainly used when stable switching status needs to remain active during operation.

Because of this, they are commonly found in:

• inspection systems
• maintenance circuits
• safety operation procedures
• manual control panels

Some older elevator control systems still use bistable mechanical structures during modernization projects.

FAQ

Why does the switch fail to stay in position?

In some systems, internal mechanical wear or contact aging may gradually affect bistable holding performance.

Can unstable switch status affect maintenance operation?

Yes. In certain elevator control systems, unstable bistable switching may affect inspection mode or maintenance response logic.

Installation Notes

Before replacement:

• contact configuration should match original specification
• terminal layout must be confirmed carefully
• switch holding direction should be checked

Some control systems use similar switch structures with different latch mechanisms.