APOTRANS AT - Transfer Switch from 125 A up to 1600 A

The Piller APOTRANS takes care of critical loads by automatically and transparently providing an alternative power source whenever the preferred power source becomes deficient. This changeover, occurring within a few milliseconds assures that the load is always fed by the optimum power supply. With APOTRANS, redundancy is engineered into the power system infrastructure, giving steadfast confidence in the performance of critical operations. APOTRANS provides optimum power to secure the load for continuous operation. Every time the preferred power source fails or its voltage no longer meets specified quality requirements, APOTRANS intelligently switches to the alternate source. APOTRANS automatically or manually returns the load to the preferred source once it is sensed to be stable.


The APOTRANS is used to improve the reliability of a power system and this is achieved by using oversized robust thyristors and internal redundancy:

  • Redundant onboard controllers
  • Triple redundant power supplies
  • Double redundant fans
  • Function check of active and inactive thyristors during each cycle

Simple Integration

The use of very robust, correctly sized thyristors allows a fuseless design of the APOTRANS. This simplifies the integration into the power system. Since there are no built-in semiconductor fuses or current-limiting MCCB’s, coordination with upstream and downstream protection devices becomes simple.

APOTRANS can be programmed to match system requirements:

  • Transfer windows
  • Input voltage tolerance
  • Input frequency tolerance

Top or bottom cable access simplifies installation Full product range available as open frame for integration into power distribution panels. 

Unsynchronised Sources

Fast and safe transfer of 180 degree “out-ofphase” sources.

3-pole or 4-pole Versions

In a TN-S system the neutrals of independently earthed sources must not be connected. The 4-pole version of APOTRANS accounts for this demand by switching the neutral also. 

File Name Size
Piller APOTRANS Static Transfer Switch Brochure 930.77 KB Download