SMC LET-400 Primary Test Equipment

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AC Current Injector up to 2.5 kA
The LET-400 is designed to perform primary tests that are necessary in substations commissioning.



It allows to perform with sufficient power, all the primary current injections to test the proper function and wiring of all the elements that compose the protection and measuring section in a substation.

The regulation system is based on a continuously variable autotransformer (Variac) that supplies to a power transformer that delivers the high current outputs and isolate the main supply from the load.


Permanent current up to 400A 1KVA in 4 Ranges.
Thermal and shortcircuit protection.


Primary injection tests.
Test of measurement and protection transformers.
In general, primary injection tests including the complete loop, such as current transformer cables, protective relays, and circuit breakers.