In-Rush Current Protection

Toroidal transformers’ excellent magnetic properties can occasionally lead to high inrush current when the transformer is turned on. The inrush current does not cause problems for low-power transformers (< 300 VA) because inrush duration is normally less than 10 ms. For higher-power toroidal transformers, we recommend the following protection:


Transformer Rating
300 VA – 1.0 kVA
1.0 kVA – 2.0 kVA
2.0 kVA – 10.0 kVA

POWERTRONIX Inrush Current Modules

These modules limit high surge currents—caused by low line impedance—to a maximum of 60 amperes peak under any line and load condition. This prevents nuisance tripping of circuit breakers and limits peak current stresses on rectifiers and switches.

Designed for use with POWERTRONIX toroidal power transformers and AC power units, such as the MIU, POWERTRONIX includes these modules with all components and systems that have power ratings greater than 2.0 kVA.

OEM versions can be configured to your needs.


POWERTRONIX Low In-Rush Transformers