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Current Range: 100 - 800 A


  • Available in 100-800A power range and both 3 pole or 4 pole installation
  • Automatically switches when supply source falls outside acceptable tolerance
  • Manual switching either remotely or via the front panel
  • Full front access for easy maintenance
  • Connectivity slot enables LAN connection and remote management


Master Switch Three-Phase is a static transfer switch for industrial and IT settings requiring additional protection from power faults. Can be used in conjunction with a UPS or as a separate standalone device.

Available for both 3 pole or 4 pole installations. Automatically switches to secondary supply if the primary source falls outside acceptable tolerance. You can also manually transfer either remotely or from the front control panel.

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Master Switch 3-Phase guarantees you a source of redundant power, providing additional resilience and protection against the failure of a single power source. Available in 8 power ratings (100-150-200-250-300-400-600-800 A) and as a 3 or 4-pole installation.

This static transfer switch easily enables seamless automatic or manual transfer to alternative, independent power sources. Also protects against load faults including overloads.


Protection Against Power Supply Faults

If one of the two input power sources falls outside tolerance levels, Master Switch automatically transfers to the secondary supply. This switching is instantaneous if the sources are in-phase, but even if they are non-synchronous the transfer time is less than 10 msecs.

Switching is also possible manually via the front panel or even remotely.


Protection Against Overloads And Load Faults

In the event of an overload, you can set the level of intervention where the MTS’s internal protection devices will block the power supply.

And in extreme cases such as a downstream short circuit, Master Switch automatically disconnects the affected load to protect the operation of other loads.


Redundant Design

Fully-independent, separate circuits supply the MTS’s internal logic. These are hot-swappable meaning you can replace them, if required, without causing an interruption to the load. Power Supply Backup functionality ensures auxiliary power from an external source if both supplies fail.

Also incorporates “fan redundancy plus”, a dual redundant ventilation system that can dissipate heat even if 2 fans fail at the same time.

Brochures and data sheets

Master Switch STS Three-phase

100-800 A Static Transfer Switch

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Technical specifications of the model