Security Roller Shutter doors on 1300VA UPS

[1st Electro]

Hello,


I have been asked by a customer to provide a backup power supply for his roller shutter doors that protect his property. The motors that supply the shutter doors are a maximum 600W 230V AC (2.6A or 600VA)


I have never been asked to provide a UPS for anything motor related.


The need of UPS is in case of a power cut to the property so the client can still gain access without mains power. There are a total of 14 roller shutters and I would specify a single UPS per roller shutter motor.


Would a 1300VA UPS be suitable to run a single 600W single phase AC motor for about 30-45 seconds just enough to gain access to the property?
I ran the shutters several times and my meter recorded 2.56A maximum.
I have used many UPS systems on PC's but I'm just not sure if there is any difference when using them on single phase motors.


You help would be greatly appreciated.


Kind regards


Midge

 

[Outspoken]

The roller shutters should have a manual over-ride chain attached, so you really only need to provide a single UPS for one door that would be decided by the customer as his/her point of access. In the event of a mains failure simply opening the door may not be enough, if the power is out for a while then he may want to close the shutter from the outside...The problem you have is that small UPS systems like that are not designed for the type of use you want to put it too, they are meant for PC and similar systems, the inrush current of the motor could damage the battery cells, depending on the quality of the internal batteries. You should also consider the fact that many UPS systems of this size use a modified(square) wave form for their output and most induction motors will not run on this, you will see an overload on the UPS the minute you try to fire it up because the motor will not run properly. The UPS you choose must be a PURE SINE WAVE type, and these costs serious money.

However, having said the above you need to be fully aware of the following;

Firstly, small electric motors (assuming single phase AC) are quite inefficient. In your case, I'd assume an efficiency of 60% (at best to be honest). This means that your 600 Watt motor uses the same "full load" power as about a 1.0 kW motor. Also, motors will use 4 to 8 times the "full load current" on startup. I would assume the median line of 6 x full load current, so your 2.56A should be assumed to be 15.36A as the startup current.

UPS's, transformers & generators are rated in VA....and this is the OUTPUT Power not the INPUT power.
Your single phase 230 volt motor uses 2.56amps at a Power Factor of 0.6. (We'll ignore the Pf for this example)
VA = 230v x 2.56A
VA = 588.8VA (Full Load)

Startup VA = 588.8VA x 6
Startup VA = 3532.8VA
Startup current = startup VA divided by 230
Startup current = 3532.8 divided by 230
Startup current = 15.36

If the customer does want all shutters to be operable in the event of a power failure then I would suggest they consider a centralised UPS system that would provide power to all shutters and perhaps lighting too...But here you are talking a lot of wedge and a specialist contractor, such as Eaton Power or Socomec

 

[1st Electro]

Hi mate,

thanks for the reply that was really helpful.
Sadly the shutters have been modified so that the manual winder has been removed to prevent people from opening them.

I suppose it's back to the drawing board to see if I can find something more suitable.

Thanks again.

 

[Outspoken]

Midge, it might pay you to speak to the client and discuss the possibility of getting in some reps from some of the decent UPS manufacturers and getting them to provide a quote...my money would be on;

Eaton Power

Socomec

Emerson/Chloride

Not only can they provide a quote, but they can give you technical information being specialists and ongoing maintenance contracts to ensure the UPS doesn't fall over just when needed.

If your looking to power all the shutters then in reality you need to be looking at something like a 25kVA UPS because you should not be running one at more than about 50% full load anyway, and your 14 motors will draw about 14kVA and thus need around 20-25kVA capacity as a minimum to handle the startup currents....unless your customer is certain that not all would be operated at the same time..however you would still need to ensure the UPS has sufficient autonomy to power the doors for a sensible amount of time whilst mains power is restored..