The following list describes all the safety components used in electrical traction elevator safety system:

• Device for locking landing doors (Hoistway Door Interlock).
• Progressive safety gear.
• Overspeed governor.
• Buffers.
• Final Limit switches.
• Other safety devices and switches.

Device for locking landing doors (Hoistway Door Interlock)

• It shall not be possible in normal operation to open the landing door (or any of the panels in the case of a multi-panel door) unless the car has stopped, or is on the point of stopping, in the unlocking zone of the door.
• The unlocking zone shall not extend more than 0.2 meter above and below the landing level.
• The hoistway door locking mechanism provides a means to mechanically lock each hoistway door and the elevator cannot leave a landing unless the doors are fully closed and secured.
• They are also interconnected electrically to prevent operation of the elevator if any of the elevator’s hoistway doors are open. Should the doors be forced open, the interlock circuit will be broken, causing the elevator to immediately stop.
• Each landing door shall be provided with a locking device satisfying the previous conditions. This device shall be protected against deliberate misuse.
• Landing doors shall be capable of being unlocked from the outside with the aid of key , which fit the unlocking triangle (Hoistway Emergency Door Keys).

Progressive safety gear

• Safety gear is a mechanical device for stopping the car (or counterweight) by gripping the guide rails in the event of car speed attaining a pre-determined value in a downward direction of travel, irrespective what the reason for the increase in speed may be.
• Progressive safety gear retardation is affected by a breaking action on the guide rails and for which special provisions are made so as to limit the forces on the car, counterweight o balancing weight to a permissible value.
• Pair of safety gears is mounted in the lower part of car sling and operated simultaneously by a linkage mechanism that actuated by overspeed governor.

Overspeed governor

• Overspeed governor function is to actuate the safety gear if the car speed exceeds 115% of itys rated value.
• Usually a cable is attached to the safeties on the underside of the car, called the governor rope. This rope runs down through a pulley at the bottom of the shaft and back up to the machine room and around the governor sheave.
• When over-speeding is detected, the governor grips the cable which applies the safeties that wedge against the guide rails and stops the car.
• The overspeed governor works on the floating principle with a cam curve and roller guided rocker.
• It is situated either in the machine room or in the head room.
• Overspeed governer is provided by a factory adjusted switch activated when the tripped speed is reached to disconnect the machine drive starting with governor pulley blocking.