Safety limit switches are designed with special features, which help to ensure the safety of machine operators and maintenance personnel who need to work in the vicinity of dangerous machinery. They can only be actuated by a special key which is securely mounted onto the machine guard. As the machine guard is closed the key is inserted into the head of the switch and various special interlocks ensure that only the correct key can operate the switch.
Once inserted, an electrical contact within the switch is allowed to close. The contact is a normally closed type, incorporating a mechanism to ensure positive opening operation.
Under no circumstances should this contact be allowed to start the machine, its function is to "prime" the start sequence of the machine which must be controlled elsewhere by a voluntary action (e.g depression of a start pushbutton).
Visit the Burnand XH Ltd website for more information on Safety Switches