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Master Switch MMS

Multi Switch STS Single-Phase
(1:1 32-63-120A)

Transfer Systems

Master Switch Single-phase (MMS) is part of the Master Switch range and offers solutions suitable for protecting single-phase loads with different power ratings. MMS is available in three sizes – 32, 63 and 120 A – and is therefore able to satisfy various requirements for the protection of single-phase loads.


Technical Specifications

Product Brochures

Main features:

Flexibility of use
All MMS versions are designed with criteria that facilitate on-site installation as well as diagnostics, control and maintenance operations. All models are equipped with a manual bypass and the hot swap function allows for rapid corrective interventions by non-specialised personnel in the event of faults.

 Load protection
With MMS transfer switch, loads are protected against critical environmental situations and mains power interference. Microprocessor control and the use of thyristor static switches ensure continuous monitoring of the power supply sources and reduced switching times between the two sources in the event of a fault. The constant monitoring of the output current allows for the rapid identification of any short circuit currents in the consumers, preventing short circuits from propagating to other loads. MMS is equipped with thermal magnetic protection for the two sources, ensuring rapid intervention in the event of faults and integrated back feed protection. MMS ensures switching times between the two power sources of less than a quarter of a cycle, both in the event of manual switching and in the event of automatic switching triggered by a fault in the power source.

 Complete diagnostics
All MMS versions are equipped with 32-character LCD displays and control panels with multi-function keys. This allows for rapid and intuitive monitoring of supply readings, switch status and environmental conditions. MMS is equipped with three standard programmable dry contacts, an input for emergency shutdown, a 232 serial connection and a slot for housing the expansion board, thus ensuring complete availability of interface solutions for remote control and monitoring.



Nominal voltage – sources S1/S2220 – 230 – 240 VAC single-phase + N
Input voltage tolerance180-264 VAC (selectable)
Switched input phases Ph+N (two poles)
Nominal frequency 50/60 Hz
Input frequency tolerance
+/-10% (selectable)
Distribution compatibilityIT, TT, TNS, TNC


Transfer type “Break Before Make”
Intervention method in the
event of failure
Hot swap function
Available transfer methodsAutomatic / Manual / Remote
Transfer time following source failure < 4 msec (S1/S2 synchronised)
10 msec (S1/S2 non synchronised)


Efficiency at full load> 99%
Noise at 1 m from front (from 0 to full load) < 40 dBA
Operating temperature0 °C – 40 °C
Relative humidity90% non-condensing
Max. installation height1000 m at nominal power (-1% power for every 100 m above 1000 m) – Max 4000 m
Reference standardEN 62310-1 (safety) EN 62310-2 (electro-magnetic compatibility)


Weight (kg)101220
Dimensions WxDxH19” x 520mm x 2U19” x 520mm x 3U
ColourRAL 7016
IP ratingIP 20

Download the Pdf here