STSW Static Switch

The AC static switch considerably increases the reliability of UPS - Uninterruptible Power Supply - and inverter systems. The unit is available in single-phase and three-phase modules.

Gamatronic offers 3 product lines:

• A. SINGLE PHASE STATIC SWITCH ST.SW.-PRO 3 KVA / 6 KVA
• B. SINGLE PHASE STSW - 3U- 3 – 30 KVA
• C. THREE PHASE STATIC SWITCH ST.SW.3-PHASE 10 ~ 150 KVA

Features:

• Two inputs, one output
• Synchronization
• Zero-time transfer
• Surge protection
• Overload protection
• Back feed protection (3,6kVA models)
• Optional PSM-STSW management software

AC Static Switches considerably increase the reliability of electrical energy supplied to critical load from inverter or UPS systems. When the load is too big for an inverter/UPS, or when an inverter/UPS is faulty, the Static Switch automatically transfers the load to a reserve source (i.e. mains power) without voltage interruption or disturbance. Gamatronic manufactures a standard single phase Static Switch (STSW1) and a three phase (STSW3) Static Switch unit with a wide scale of nominal powers.

Parallel UPS Systems with a Static Switch

Equipping a parallel UPS system with an external static switch significantly improves system MTBF by ensuring that the output voltage is not interrupted even if one or more UPS units are faulty. The external static switch unit transfers the load to the mains if the parallel UPS system can not supply the correct voltage to the load. The inverters of parallel UPS systems are synchronized to each other with extremely high accuracy. They are also synchronized to the bypass when its voltage and frequency are within specified limits. A special signal bus is used for synchronizing UPS systems. In the event that a UPS system’s output voltage falls below the set limits due to overload or inverter failure, it is detected by the static switch which transfers the load to the bypass. The detection time is less than 1msec, resulting in a transfer process that is safe for any kind of load. For additional improvement in MTBF the static switch is usually connected to the bypass so the load is connected to the bypass when the static switch is not operating.