Auxiliary Switch – The Eyes of the Circuit Breaker

In modern electrical and control systems, every action — even the smallest one — must be monitored, recorded, and controlled.
The Auxiliary Switch is a smart yet simple component designed to tell the system what’s really happening inside the breaker:
whether it is ON, OFF, or has tripped due to a fault.

🔹 What Is an Auxiliary Switch?

An auxiliary switch is an additional electrical contact unit that is electrically isolated from the main power circuit, yet mechanically synchronized with the main contacts of the breaker or magnetic protector.
In simple terms — when the main breaker opens or closes, the auxiliary switch changes its state simultaneously, sending a signal to the control system.

The contacts may be:

• NO (Normally Open) – closed when the breaker is ON.

• NC (Normally Closed) – opened when the breaker is ON.

• Or a combination of both in a single SPDT (changeover) structure.

🔹 Why It Matters

In critical environments — defense, industrial, or medical — there’s no room for guesswork.
A control system or load-management computer must know, in real time, whether a breaker has been activated, tripped, or manually switched off.
The auxiliary switch provides this information reliably, precisely, and instantly.

Key advantages:

• Remote monitoring and control – allows PLC or SCADA systems to track breaker status in real time.

• Smart maintenance and alerts – forms the basis for alarms and automated fault diagnostics.

• Safety integration – enables timed disconnection or prevents unintended restart after a trip.

• Isolation between power and control circuits – keeps low-voltage control (e.g., 24 VDC) separate from high-voltage power (e.g., 230 VAC).

🔹 Auxiliary Switches in Airpax™ Products

In Airpax™ magnetic circuit breakers, auxiliary switches are an integral part of the design —
offered either as an internal option within the series pole, or as an external control module.

Each contact is engineered for:

• Simultaneous operation with the main contacts, ensuring accurate status feedback.

• Complete electrical isolation, allowing mixed-voltage operation.

• Optimized contact materials – gold or silver, chosen per application:

  • Gold contacts (REG) for very low-voltage signals (below 6 VAC or 5 VDC).

  • Silver contacts for higher loads (up to several hundred mA).

• Reliable operation both under manual actuation and automatic trip, ensuring accurate event signaling.

For example, in the IAL, LEL, and AP series, Airpax™ auxiliary switches are available with codes such as –IREC4, –IREG4, –IREC5,
and can be configured for any Trip Series arrangement.

🔹 Typical Applications

• Industrial control panels – monitoring motor protection, frequency converters, and multi-phase power systems.

• Defense and aerospace systems – feedback to control logic or data logging units.

• Medical and precision instrumentation – strict supervision of power and safety interlocks.

• Energy and infrastructure – real-time monitoring of DC/DC converters, power supplies, and UPS units.

• Industrial IoT – acting as a “status sensor” transmitting real-time data for remote analysis.

🔹 Simple Integration – Major Impact

Though small, the auxiliary switch directly enhances:

• Operational reliability,

• Reduced downtime, and

• Predictive maintenance capability.

Airpax™ switches are built to withstand the harshest environments —
shock levels up to 100 G, vibration up to 2000 Hz, and insulation performance meeting UL1077, VDE, and MIL-PRF-39019 standards.
The hydro-magnetic design of the AP and IAL series ensures stable operation under extreme temperatures and vibration conditions.

🔹 Amironic – Official Airpax™ Representative in Israel

Amironic Ltd. proudly represents Sensata-Airpax™ in Israel — one of the world’s leading manufacturers of rugged magnetic circuit protection solutions.
With a broad range of products — from auxiliary switches to precision current protection and three-phase breakers —
Amironic provides reliable, compliant, and easily integrated solutions tailored for every Israeli application.

⚙️ In Summary

The auxiliary switch may be small, but it’s the intelligent sensor that lets your system “see” what’s happening behind the panel.
With Airpax™ engineering and Amironic’s local expertise, these switches deliver dependable monitoring and control —
ensuring operational continuity in every environment, under every condition, and at every engineering standard.