ERD is an elevator-installed mechanism that acts during power shortages that limit the lift’s performance. In the event that the main power source fails, this emergency equipment supplies a 3-phase power supply to the elevators. An ERD is distinct from an auxiliary or emergency power system or standby generator in that it provides near-immediate protection from interruptions in input power by supplying energy stored in batteries via a specialized power bank.
Let’s explore what makes an ERD UPS better than Online UPS:
1. Smart Intelligence ECU. Electronic Control Unit fitted in the lift.
For ERD UPS, it shows the various parameters as well as it has an inbuilt speaker to announce.
For Online UPS, there is no such device as Online UPS always remains in battery mode.
2. Intelligent door opening of Elevator.
ERD UPS has three low-battery alarms so that the user never gets stuck in the lift and Online UPS has a single low-battery alarm it stops after the first alarm and can’t be operated and the user can get stuck anywhere in between the floors.
3. Remote Monitoring.
ERD UPS has a sophisticated monitoring app that keeps the data of power failures and low voltage high voltage parameters stored as well all 3 phases are shown and power is monitored continuously.
Online UPS doesn’t have any monitoring related to the lift as a dedicated feature.
4. Efficiency in Grid mode and power consumption when the Grid is available.
Since the ERD is bypassing the power and charges the battery bank so it has the highest efficiency as the lift load varies drastically.
Online UPS has the lowest efficiency and the power bill is very high so when the grid power is available as it takes power from the grid to convert AC-DC-AC power
5. Cost saving.
ERD UPs use PFC-based battery chargers to save electricity and cost.
Online UPS uses 3/6 pulse/dual converter-based battery charger which has low P.F. and consumes more electricity hence costing more.
6. Charger efficiency or power consumption at the time of charging of battery bank.
Since the ERD works on Bidirectional technology it has very high efficiency in charging as well as Battery mode.
Generally, the efficiency of Online UPS is poor on charging compared to the ERD
7. Digital Display on the Equipment
ERD UPS has the following displays: Elevator stationery, Passenger Rescue, and Elevator running.
Online UPS has a general display related to power.
8. Battery low warning.
ERD UPS has a low battery capping at 75%. It can give 4 types of battery warnings and battery empty warnings before opening the door and stopping the functioning of the lift. Even after the low battery warning, it will continue to function till the last floor.
Online UPS doesn’t have any such feature and lifts and stops anywhere once the battery goes low which can create panic.
9. When there are voltage variations at the grid.
In the ERD the grid voltage is not corrected up to a defined low and high voltage and bypasses the voltage and once the limit reaches the low level and high level it immediately switches to the Battery mode which is done less than 3 msec so the lift moves without any jerk and the ECU displays and announces this continuously.
The Online UPS provides the correction of voltage continuously which takes extra current from the Grid and battery to maintain at 415V+-1% which is a big waste of energy from the grid and battery and battery life reduces and sometimes the battery is already discharged when the power cuts take place and not able to give the desired back up time.
10. The flexibility to add solar capacity.
In the ERD we have kept a provision that by installing an external charge controller we can make it Solar ready and the lift can completely function on solar power without the grid or having grid power.
However, in the Online UPS topology, there is no such flexibility.
11. Overall efficiency
The online UPS simply needs a bigger battery bank size to run a similar load when compared to ERD UPS.
Su-vastika has developed a cutting-edge Emergency Rescue Device (ERD) that delivers up to ten hours of power backup for critical systems like elevators and escalators.
Recently they even secured a patent from the Government of India for their ERD technology. The title of patent 396079 is “A System and Method for Providing Backup to Consumer-Friendly Elevators and Lifts.”
Indian start-up Su-vastika is proud of its lift accident prevention system. Their equipment can be customized for small to big loads of up to 500 KVA and can run on lead-acid or lithium batteries. It can also provide power backup for up to two days and does not require an air conditioner. Furthermore, it is BIS certified. Please check their website for more details.
