View our range of Transfer Switches – Siel Energy Systems Gloucestershire. If you have any queries regarding any of our products then get in touch.

Siel Energy Systems can supply and install Automatic Transfer Switches and Static Transfer Switches commonly referred to as ATS or STS respectively.

Siel can provide a full range of STS products to suit your needs including:

  • Single phase 19’ rack mounted STS 16 – 32Amps, the Siel MTR STS
  • Single phase 19’ rack mounted STS 32 – 120Amps, the Siel MMS STS
  • Three phase standalone STS 63Amp – 1600Amp, the Siel Exchange STS
  • Open frame STS for building into bespoke switchgear cabinets, the Siel Exchange Bespoke STS 63 – 1600Amps

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In the case of the MTA ATS, the product provides direct distribution of eight 10 A IEC consumers or one 16 A IEC consumer in a system with two input power lines (two mains inputs, or two UPS).

The MTA ATS is able to connect to either of the two input power lines, whilst simultaneously monitoring the power uptake. Protection against load faults If one of the loads fails (e.g. short circuit), MTA ATS disconnects the group of sockets where the load is connected, thus preventing other loads from being switched off (i.e. in the event of poor selectivity of the protection devices).

If one of the two power sources falls outside tolerance levels,  MTA ATS will transfer the consumers to the second power source (switching is instantaneous if the two sources are in phase).

An STS is normally part of a dual bus system providing critical equipment with 2 possible supplies.  An STS provides faster transfer times than an ATS due to the solid-state devices used for switching.   Each supply would normally be fed from an on line double conversion UPS.  Should one supply fail, the STS will automatically transfer the critical load over to the alternative supply.

In the case of the Siel Exchange STS the principle of operation is as follows:

Dual input AC power is derived from two independent sources one of which is set as the ‘priority’ line. An automatic ‘break before make’ transfer to the alternative source will occur should the preferred source exceed pre-set tolerances or fail completely.   Assuming both input supplies are synchronised the transfer time is typically 4 milliseconds.

In its standard configuration the switch is composed of two bi-directional thyristor switches for each phase, equipped with protection and system control logic.  4 pole versions include a neutral line switch.   Input, output and bypass switch-gear is also included.

Mounted on the front of the cabinet door is a comprehensive control and interface panel providing:

  • Synoptic display providing LED indication of system operational status.
  • LCD providing metering and other operational status indications including visual display of any current alarms.
  • Pushbuttons for metering selection and control.

All switches are fitted with a ‘customer interface’ board providing:

  • Volt-free contacts.
  • RS232 communication
  • Optical communications port.
  • RS485 communication with Modbus protocol.
  • Compatible with TGS 24/7 remote monitoring