Safety Relay
We use safety relays/magnetic on-off relays in many places; these prevent that a machine powers back on after a power loss.
It also prevents powering back on after someone pressed the emergency button.
And it ensures the power is turned off immediately after pressing the emergency button, the stop button, an overheat/overload situation or a lock-out situation. In some cases it is also integrated in the [Access control system].
3 phase power machines
Most are a variation of the Large Stationary Grinder, Metal Mitre Saw or the Cirkelzaagtafel SCM L'Invincible / Large tablesaw circuit. These are based on a product such as: https://www.hydrauliek24.nl/motor-beveiligingsschakelaar-7-10-a or on normal contractors with a load limiter (see yellow crate for more of these).
Small machines
Some of the small machines use a 4 or 5 pin `on-off' button such as https://www.amazon.de/-/en/Hefddehy-Waterproof-Magnetic-Button-220-240V/dp/B0BYNGHLJ5/ref=sr_1_10 or https://www.amazon.de/-/en/KEDU-KJD17-Flush-Mounted-Switch-Voltage/dp/B07956F8TN/ref=d_pd_day0_sccl_2_1/257-4034223-4086038
These are wired as thus:
