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Telephones/Uninterruptible Power Supply for Elevators.



Can Uninterruptible Power Supply (UPS) provide a battery backup for Elevators / Lifts in case the mains power goes up ?.

Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

ANSWER: Yes, however the size of the UPS must be considered because the elevator requires a significant amount of power, especially if the elevator is fully loaded. When sizing the UPS, you would have to take into account what the power requirements would be for the elevator going up from a standstill with a full load. In addition, you would need to include a safety margin to account for the batteries not being at full capacity due to loss of capacity as they age.

In determining the size of the battery required, you must also consider how long you expect the normal power outage will be. The longer you wish to have the elevator operational, the larger the batteries. this timeframe would have to be considered during peak usage times, allowing for the elevator to comply with the specifications during all worst case situations.

There would be costs associated with this, which might be quite substantial for the batteries and the power supply itself. Further, the batteries would need to be checked and or replaced on a regular maintenance cycle, so there is an on-going cost to maintain the system, probably including replacing all the batteries every few years.

---------- FOLLOW-UP ----------


Thank you.

Is it possible to use more than One UPS in series after computing the elevator power consumption ?.


1. When the mains supply goes, the elevator will come to ground floor for the people to exit / come out of the lift.

2. The Elevator will continue working for specific INTERVAL - hours depending upon the UPS Batteries power output. The UPS Batteries will be charged from AC Mains supply once the power is restored.

3. Elevator controls will indicate to the people inside the elevator using Alarms or LED Blinking that the elevator is using the UPS Battery Backup power and also indicating the Battery Backup time remaining for the Lift Operational. For example : 3 Hours remaining, with a decrements counter
in Hours:Minutes:Seconds.

Regarding the second requirement, we may have to use more than one UPS ?.
Regarding the third requirement, Can this be possible to implement within
Elevator electronic panel controls  ?.

Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar


My replies are:

1) Regarding the second requirement, we may have to use more than one UPS ?.

The battery size could be increased in order to increase the capacity. How much it can be increased would depend upon the make and model of the UPS. A custom made product could potentially add any number of battery banks in parallel to increase capacity.

You would not use multiple UPSs simply because the output is AC, and the output would not be additive unless the outputs were perfectly in phase with each other. There are other technical issues and the costs would be higher.

2) Regarding the third requirement, Can this be possible to implement within
Elevator electronic panel controls  ?.

Yes, it could be done, but the question is how accurate the indicator of the remaining time would be. To achieve the greatest accuracy, you would have to somehow determine the average anticipated power draw during that time period. If you simply went on the momentarily current draw, then the estimate time would drop significantly as the elevator moved and increase when it stopped, so you would not achieve a clear indication of how much longer you could use it. There may be experts in the field who have come up with meas of more accurate estimation, but unless that can be shown to be possible, it might be better to simply show an estimate of the amount of charge left so that passengers would know when it was getting low and getting risky to remain on board in case they get stuck.

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Tom Smith


I can answer questions regarding product approvals, including areas such as Product safety, Electromagnetic Compatibility (EMC), Telecommunications, Environmental requirements such as RoHS (Restrictions on Hazardous Substances), WEEE (Waste Electrical and Electronic Equipment), and international approvals requirements.


I have been involved in product approvals for over 25 years, working both for major manufacturers, design organizations, and two major testing laboratories. I have experience putting products into countries around the world, working with various approvals agencies, and have been involved in various standards development agencies (Product Safety, EMC and Telecom). I was the Senior Approvals Engineer at the first private telephone approvals laboratory in Canada, and have been involved in the development of Industry Standards for telephone and telephone products.

- Senior Member of IEEE - Association of Professional Engineers, Geologists, and Geophysicists of Alberta (APEGGA) - Professional Engineers of Ontario (PEO) - Terminal Attachment Program Advisory Committee (TAPAC) which is under the jurisdiction of Industry Canada (Department of the Gov't of Canada) - Canadian Standards Association

B.A.SC (Electrical Engineering)

Awards and Honors
- Only Approvals Liasion Engineer (ALE) ever appointed by AUSTEL (AUSTEL is no longer the authority in Australia, and the ALE program was also replaced in 1997) - Former Deputy Approvals Liasion Engineer appointed by the British Approvals Board for Telecommunications (BABT)

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