Smart Elevator Maintenance | EMEA

Circuit designs that can only switch modes when powered up create a risk of injury and death
Are you aware a power failure that occurs when elevator manufacturer maintenance personnel are carrying out inspection work can increase the risk of injury or death?

Conventional elevators utilize mode control technology so that the system can be switched to inspection mode only when the circuitry is powered up. Therefore, if a power failure occurs during inspection mode, the circuitry will be powered off and it will automatically return to the normal operation mode. If the maintenance personnel do not notice this and someone presses the lift button after the power is restored, it may result in injury or death. In order to avoid such risks, it is necessary to implement safety measures outlined in the new European elevator standards "EN81-20/21. From now on, similar standardization efforts are expected to also be implemented in Japan and China.

Using keep relays to build simple and safe electrical systems
It is important to think of elevators as long-service-life public vehicles that need to withstand being hit by disasters and sudden power outages. In the new European elevator standard "EN81-20/21", all electrical systems are required to have safety measures that are equipped to handle emergency situations. However, rebuilding electrical systems requires a very complicated circuit design, and takes up a significant amount of money and labor.

Therefore, IDEC recommends the use of keep relays which can enable electric system safety measures in a simple manner. Unlike conventional relays, keep relays have two coils with permanent magnets. When one of the coils is energized, the system switches to inspection mode. When the other coil is energized, it will switch to normal operation mode. This allows easy construction of a flip-flop circuit (latch) that can individually control the two different operation modes.
 

RY2KS Keep relay and Internal Circuit
(The above figure shows the reset state as viewed from the bottom.)

By changing conventional relays to keep relays, it is possible to create a system that does not allow the mode to switch from inspection mode to normal operation mode even if a power failure occurs.

Contact IDEC for elevator safety solutions
At IDEC, we offer a number of other solutions to improve elevator safety other than keep relays. We provide various safety equipment and control equipment conforming to SIL 3 standards, and comprehensive solutions from standalone switch products to control boxes to allow compliance with new elevator standards EN81-20/50. We have various skills and knowledge to help our customers solve a variety of problems. Contact IDEC if you have any concerns regarding elevator safety improvement measures.