These transformers up to 63 VA provide a safety extra-low voltage for the supply of control current circuits, switching relays or Insta contactors in continuous operation as an alternating voltage power supply for 8 V, 12 V, 16 V, 24 V und 32 V AC.

Higher output voltages will occur in the event of low-load or no-load operation. Siemens safety transformers are protected against short circuit or moderate overload by a PTC resistor. After a short circuit, the primary current must be briefly disconnected from the mains before restarting.