Why Choose the Mersen USFMAC11 Auxiliary Contact?
The Mersen USFMAC11 is a compact auxiliary microswitch contact designed for use with Mersen UltraSafe™ three-pole fuse modules. It provides an early-break and late-make switching function that supports safer isolation and improved control integration in industrial motor circuits, machinery and automation panels.
When the USFMAC11 is installed in a compatible USFM fuse module and connected to an adjacent contactor, opening the fuse extractor handle operates the microswitch before the fuse is disconnected. This allows the contactor to drop out and remove the load, helping reduce the risk of opening the fuse module while the circuit is energised under load.
Its slim 9.1 mm-wide design integrates neatly with compact Mersen USFM assemblies and 45 mm IEC contactor arrangements. The accessory is suitable for both Midget and Class CC UltraSafe fuse modules, making it a practical choice for OEM machinery, motor control panels and industrial electrical systems requiring auxiliary status or interlocking functionality.
Key Advantages
- Provides an early-break and late-make auxiliary contact function.
- Helps ensure the associated contactor drops out before fuse disconnection.
- Supports safer fuse replacement and maintenance procedures.
- Compatible with Mersen UltraSafe USFM three-pole fuse modules.
- Suitable for both Midget and Class CC USFM configurations.
- Compact 9.1 mm width minimises additional panel-space requirements.
- Microswitch operation enables electrical interlocking and status signalling.
- Designed for industrial motor control and automation applications.
Key Features
- Mersen UltraSafe™ USFM accessory.
- Early-break / late-make microswitch.
- Designed to operate when the fuse extractor handle is moved.
- Supports connection to an adjacent IEC contactor.
- Compatible with Mersen USFM Midget and Class CC fuse modules.
- 200 kA short-circuit current rating as part of the compatible assembly.
- Compact and lightweight construction.
- Suitable for auxiliary control, interlocking and indication circuits.
- Simple integration into existing USFM assemblies.
- Supplied as a single accessory unit.
Reliable Interlocking for Industrial Fuse Modules
The Mersen USFMAC11 provides a mechanical-to-electrical interface between a compatible fuse module and an external control circuit. When the fuse extractor handle begins to open, the microswitch changes state early enough to signal or de-energise an associated contactor before the fuse contacts separate.
This operating sequence improves maintenance safety and helps protect connected equipment from switching under load. Its compact design also allows panel builders to add auxiliary control functionality without significantly increasing the footprint of the USFM motor protection assembly.
Typical Applications
- Industrial motor control panels.
- IEC contactor and overload relay assemblies.
- OEM machinery and production equipment.
- Electrical interlocking circuits.
- Fuse module status signalling.
- Industrial automation systems.
- Pumps, fans and conveyor control panels.
- Manufacturing and processing equipment.
