Master Switch Three-phase
Static Transfer Switch
Installing a Master Switch static transfer switch provides additional resilience and protection from the disruption that can be caused by the failure of a single power source. The result is the absolute protection of industrial utilities and critical information technology against power supply and load faults.
16 models in this range · quoted to order by an authorized Riello UPS reseller

Highlights
- High reliability
- Hot Replacement function
- 3- or 4-pole version
- Advanced communications
Models & ordering
Riello model designations are the order codes. Each model is quoted to order; open a model for its full specification and to request pricing and lead time.
| Model | Rated power | Active power | Dimensions (h w d) | Weight | |
|---|---|---|---|---|---|
| MTS 100 3P | — | — | 1500x685x530 mm | 150 kg | Quote |
| MTS 150 3P | — | — | 1500x685x530 mm | 155 kg | Quote |
| MTS 200 3P | — | — | 1770x685x580 mm | 195 kg | Quote |
| MTS 250 3P | — | — | 1770x685x580 mm | 200 kg | Quote |
| MTS 300 3P | — | — | 1770x685x580 mm | 225 kg | Quote |
| MTS 400 3P | — | — | 1770x685x580 mm | 230 kg | Quote |
| MTS 600 3P | — | — | 1900x950x730 mm | 340 kg | Quote |
| MTS 800 3P | — | — | 1905x1250x850 mm | 515 kg | Quote |
| MTS 100 4P | — | — | 1500x685x530 mm | 155 kg | Quote |
| MTS 150 4P | — | — | 1500x685x530 mm | 160 kg | Quote |
| MTS 200 4P | — | — | 1770x685x580 mm | 205 kg | Quote |
| MTS 250 4P | — | — | 1770x685x580 mm | 210 kg | Quote |
| MTS 300 4P | — | — | 1770x685x580 mm | 235 kg | Quote |
| MTS 400 4P | — | — | 1770x685x580 mm | 240 kg | Quote |
| MTS 600 4P | — | — | 1900x950x730 mm | 375 kg | Quote |
| MTS 800 4P | — | — | 1905x1250x850 mm | 560 kg | Quote |
Ships from and sold by A5 IT.
| Input | |
| Voltage | 380 / 400 / 415 V three-phase + N |
|---|---|
| Voltage tolerance | 180 / 264 (selectable) |
| Frequency | 50 / 60 Hz |
| Frequency tolerance | ±10% (selectable) |
| Switched input phases | 3 (3-pole) |
| Distribution compatibility | IT, TT, TNS, TNC |
| Environmental | |
| Color | RAL 7024 |
| Protection rating | IP20 |
| Other compliances | EN 62310-1 (safety) EN 62310-2 (electro-magnetic compatibility) |
| Noise (at 1 m) | 55 dBA |
| Operating temperature | 0 °C - +40 °C |
| Storing temperature | -10 °C up to +50 °C |
| Relative humidity | 5-95% non-condensing |
| Transport | Pallet jack |
| Available transfer modes | Automatic / Manual / Remote |
| Data | |
| Weight | 150 kg |
| Dimensions (h w d) | 1500x685x530 mm |
Characteristics
Operating principle Master Switch guarantees a source of redundant power, allowing the load to be switched between to alternative and independent power sources. Switching can be automatic (when a supply source falls outside of acceptable tolerances) or manually done by an operator from the front panel or remotely.
Protection against power failures If one of the two power sources falls outside tolerance levels, Master Switch will transfer the consumers to the second power source (switching is instantaneous if the two sources are in phase).
Protection against environmental disturbances Overloads and load faults In the event of an overload, the user can decide the level of intervention of the internal protection devices in order to block the power supply. In the extreme case of a downstream short circuit, Master Switch disconnects the load in order to avoid jeopardising the operation of the other loads (i.e. in the event of poor selectivity of the protection devices).
Accessibility The layout of the moving components and parts is designed to ensure easy frontal access:
Advanced communications Master Switch provides information, measurements, statuses, and alarms via the LCD display. The STS is compatible with PowerShield 3 supervision and shutdown software for Windows operating systems 10, 8, 7, Hyper-V, 2019, 2016, 2012, and previous versions, Mac OS X, Linux, VMWare ESXi, Citrix XenServer and other Unix operating systems.
- power cable connections that are easily accessed with entry from below;
- boards housed in a dedicated area for rapid diagnosis / replacement;
- all parts subject to monitoring, maintenance and/or replacement.








