Elevator on UPS 2

[AusLee]

Hello,

I have an elevator bank of 100 kVA. I intend to put it on a 150kVA UPS. Will that be enough? and could you please tell me, when the mains power is not present, what does the UPS do with the regenerated power when the empty car are going Up due to the descent of the the heavier counter weight?

 

[davidbeach]

Have you talked to the UPS vendor? Elevators would make a horrible load for a UPS. A generator and enough lighting load to absorb the regenerated power would be a far better solution.

 

[itsmoked]

Agreed!

The only other choice is if the elevator is VFD controlled and you can provide a load bank while the mains are gone.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[rbulsara]

Who comes up with such wonderful ideas?

 

[MikeHalloran]

People who know little about UPSes or elevators come up with ideas like that.

But don't scorn them. If they have enough money, they represent a business opportunity.



Mike Halloran
Pembroke Pines, FL, USA

 

[BJC]

In this part of the world elevators are strictly requlated. I don't think you could put one on a UPS. If you did I would ride in it.
I think if you called most of the elevator makers and ask about your ideal they would talk to you ( after they stopped laughing).

 

[AusLee]

Ok, sarcasm noted

About the money: not an issue.
About the generator: there are back-up generators.

I did not explain why i want the UPS, i thought some of the ones who answers this question knew enough about elevators to understand the reason. But anyway: i have talked to OTIS and Thyssen and they both told me that they can not do anything about the Recycle feature embedded in the control of the elevators, which is programmed to take the car to a predefined floor after a power failure. This is exploited by gangsters as one enters the cabin and another cuts off and restores the power, thus sending the elevator to the lowest floor (car park) otherwise accessible only to passengers through a key. This can be simply overcome by defining another floor in the elevator's control. My building is tall and the traffic is high and i do not want to have wasted time over a procedural constraint that can be overcome by eliminating the interruption through a UPS.

davibdeabch: as explained above, i do require a UPS, if you could please help me get the correct rating.

itsmoked: the elevators are controlled by variable voltage and variable frequency technologies and there will be a resistor bank in the machine room for the reactive energey - thank you for pointing that out as i missed it and now i will only require that the resistors be rated to dissipate the amount of heat and even more, it seems there is not problem of reactive power after all Thus i think the UPS can be simply rated to the load with some extra 25% for safety. will that be correct?

BJC: i do not think that what you are saying is correct. I have had plenty of elevators put on a device called "Emergenzamatic" (google the name and you will get the italian manufacturer, many elevators brands buy from them instead of inventing a system of their own). This equipment has the purpose of getting the elvator to the nearest floor (up or down) and then open the door and leave it open. So it is a small UPS but with stored procedures. Therefore i do not think that there is any place in the world where it is regulatory prohibited to have elevators on UPS. In fact, it is mandatory to have, at least, the emergency lighting and the ventilator fan in the cabin on back-up source (DC or from a small UPS) with sufficient autonomy for at least one hour.

I hope the above calrifies some information i missed in my question. So then what shall be the rating of the UPS please?

 

[waross]

Regeneration is a real issue with generators as well as on a UPS.
If a generator was used for an elevator only and no provisoion was made for regenerative energy, There are conditions under which the elevator will "motor" the diesel.
A basic safe system would have a resistor bank of sufficient capacity to absorb the regenerated energy permanently connected in parallel with the elevator drive. The generator or drive would then be sized to carry both the elevator drive and the resistor bank.
If automatic switching of the resistor bank is desired for the sake of economy of energy consumption, this should be done with someone familiar with elevator codes and controls.
I would talk with the "Emergenzamatic" people.
If their device is a true UPS you may be able to work with them to add enough batteries to run the elevator until the generator comes on-line.
You may also be able to work with the "Emergenzamatic" people to use their device with security sensitive floors "locked out". This will avoid the long trip to the bottom. 15 seconds is all it should take to get the generator online. I would leave a suitable load bank permanently connected to the generator.
You may also consider a rotary UPS such as

http://www.upsci.com/UPS-rotary.htm

this may be your answer in one package with no need to modify the existing elevator controls and the resulting approvals problems.
You would still want the resistance bank for regeneration.
respectfully

 

[ScottyUK]

Your UPS power requirement is right at the bottom end of the power range for the rotary designs offered by Eurodiesel and Anton Piller, but these machines are among the best for fault clearing ability. Naturally they're also expensive but you said money wasn't a big issue (wish I had that problem ) so it may be worth exploring. These things are popular with the big financial organisations, so draw your own conclusions w.r.t. reliability. Keep away from the rotaries which use a power electronics converter and a rotating energy store - they have all the negative points of both technologies and few of the positives of either.

http://www.euro-diesel.com/total_technical.html

----------------------------------

Sometimes I only open my mouth to swap feet...

 

[AusLee]

Hello and thank you for your answers.]

For using the Emergenzamatic as a UPS: increasing the size of the batteries will not imporve the predefined performance, as its built-in task is to bring the car to the nearest floor only (it does it at slow speed). If you meant to contact them in order to modify the function of the equipment, i am sure they can do it but it is not standard policy for me: i prefer the products i use to be from the main manufacturing line, for many reasons: 1) maintenance: people who know how to fix the traditional box will mess my modified one, 2) availability: it is much easier to get a spare control card in case of failure than to order a new custom designed one, ...

For the fly wheel generator, i turned myself down from the idea because i have several generators in parallel for the building. Having one fly-wheel means that i must program the sychronization panel to use that one always as primary and to program the ATS supplying this load to be the first one to switch. The rest of the ATS will switch when the other generators come in synchro, otherwise if they close all at the same time i will have overload on the flywheel and its protection will trip.

Instead of going through this complication, i prefer to put the elevators on UPS; as noted, there will be switched resistor banks for the regenerated power, but i would like to have your opinion on the sizing criria: how large must a UPS be to supply a 100 kVA bank of elevators? I prefer to use the off-line technology, no line-interactive and no dual conversion, the harmonnics of the VVVF will be filtered by dedicated devices, will that be applicable?

 

[dpc]

What happens when the UPS fails?

 

[BJC]

Here in backwoods all elevators installations get reviewed and approved by the local electrical inspector and the fire marshall. They really don't care about security, their concern is fire and getting people out in the fire. If you were to propose an installation that was new and unproven you would not have much of a chance getting it approved.
All the elevators I have worked with are connected a Diesel generator that has at least 3 hours of fuel. The generator is on the standby system and will be powered in less than 60 seconds. In a bank of elevators they may not all be powered by the standby system. All elevators return to the ground floor in a fire ( Thats in the Building codes).
Firemen are pretty gutsy to ride the elvator in a burning building. It's probably why they are reluctant to approve anything that isn't proven by a long history.

 

[rbulsara]

So where would an elevator "car jacker" drive to, if he succeeds in high jacking one?

Why would you not trap a high jacker right in the "car"?

 

[dydt]

how about bank of batteries tied to the +/- of the VFD equipped with blocking diode(s)?

 

[itsmoked]

That was my thought too dydt!

How about hanging a large battery bank on the DC bus of the VFD and then run a much smaller line UPS or an inverter off the bank to run the elevator controls.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[dydt]

you can have a separate battery charger for the bank of batteries. the batteries ride on the
vfd dc bus in such a way that a diode prevents back feeding. when the mains disappear the battery
takes over via the diode. size up the battery to cover the time necessary for the generator to take the load.
any thoughts?.

 

[AusLee]

Thank you, problem solved.

dydt - Merlin Gerin UPS told me they have this feature built in their Galaxy range, with the resistor bank the problem is resolved, UPS on its way soon.

For the firemen, there is a difference between power failure and fire condition. The elevator's control panel has a dry contact for fire alarm, when it closes, it automatically initiates the fire procedure: sending the car to the gtound floor and requiring the use of the firemen key to respond to further commands. Actually there is more than this: the elevator's shaft must be all concrete, so if it is part of a bank then there must be separation between the two (though there are ways to relax this). The generators have daily tanks for 8 hours of operation and are linked to a bulk tank with ...

what happens if the UPS fails is: people will get stuck for 10 seconds, after which they will be taken to a pre-programmed floor.

 

[bjenks]

Never put a machanical load on a finite electronic source such as a UPS unless it is way oversized and I mean at least 5-7 times. Everytime the motor starts up it will go to bypass. Of course murphey's laws says that when in bypass, you will loose power.

 

[tinfoil]

I suspect you've considered this, and no sarcasm intended, but...

Won't your hypothetical gangsters who are smart enough to cut the power during a robbery ALSO be smart enough to know about the elevator's behaviour during a fire?

Can they force the elevator(s) to the ground floor simply by activating one or more fire alarm switches?

Your UPS arrangement would simply be bypassed/pre-empted at that point, wouldn't it?

I can't imagine a fire marshall anywhere that would let you monkey around with THAT pre-empt!

 

[AusLee]

tinfoil - the gangsters behavior has been noticed by others and communicated to the manufacturers. Only when i was doing a test and noticed that we've got to the wrong floor that this function was explained to me and from there i verified with another manufacturer and they confirmed the same.

Note that in that case, which is not my preocupation, the intended floors were the car parks at the lower basements, which are not normally public entry floors. Therefore, in case of fire, the elevators will go to the ground floor, not the basement. So activating the fire alarm using a manual call station will do them no good.

The purpose why i'm having them on UPS is purely and simply for luxury purposes. I would even use the flywheel generator if i had only just one, but with 4 and alternating priorities, it is a feasible but not striaght forward solution.

bjenks: actually you can see on the elevator's control panel the current and power and ... and i am sure that VVVF elevators start smoothly from zero amps to full load (if the car trip is long enough). Therefore the 5-7 starting current is not applicable.