Instantaneous trip relays, whose contacts change instantaneously from the rest position to the working position when the coil is energized. The contacts return to the rest position when the coil is no longer energized.
This range includes relays with 2, 4, 8 and 16 contacts, with operating times from 3 ms to 8 ms, depending on the model.
All the relays include a diode in parallel with the coil (see auxiliary relays with overvoltage protection characteristic) and comply with the shock and vibration standards, related to the relays with seismic characteristics.
There are two main types of fast trip relays: