Last edit: 28/06/2023
Explanation of emergency operation functions
We all have in mind the Emergency Stop pushbutton or rope: nearly all machinery have at least one! As soon as that button is pushed, the machine stops or goes to a safe state. However, there are situations whereby a safe state can be reached only by activating a movement.
Moreover, there are two types of Emergency operations:
- The first related only to Electrical Hazards
- The second related to all other Hazards.
In order to eliminate an “electrical hazard”, components suitable for both interruption and isolation are needed: possible components are Disconnectors, circuit breakers or a plug/socket combinations.
In order to eliminate a “mechanical hazard” components suitable for energy interruption are enough. A typical component is the Contactor, or a Magnetic or Solid state Motor Controller (in north American language).
That means, there are four types of emergency operation functions:
- Emergency stop: an emergency operation intended to stop a process or a movement that has become hazardous.
- Emergency start: an emergency operation intended to start a process or a movement to remove or to avoid a hazardous situation.
- Emergency switching off: an emergency operation intended to switch off the supply of electrical energy to all or a part of an installation, where a risk of electric shock or another risk of electrical origin is involved.
- Emergency switching on: an emergency operation intended to switch on the supply of electrical energy to a part of an installation that is intended to be used for emergency situations.