UPS Sizing

How Many Motors??

What are Max Amps??

What Power Factor??

These will give you the size and specs for the UPS.

Contact a reputable UPS Supplier for assistance or better still contact 3-4 and ask them for recommendations.

The 10min Battery life will depend on the number & size of the battery blocks, which will be best identified by the UPS supplier.

Make sure you specify "10 minute Autonomy at end of battery life" with a discharge on 80% or less.

This is important if you need 10 minutes to clear the pipes as battery autonomy reduces with age.

A Rotary UPS will not help you since you have a 10 minute runtime requirement.

Regards,
Sapper.

Hi Sapper,

Thank you very much of your very valued infomation.

Regards

Hi Sapper,

I have only one unit of 3Kw 3phase motor, max ampere 5.5Ampere and PF at 0.7

Thank yo very much of your prompt reply

Regards

I would suggest at least a 5-5.5kVA UPS and batteries for 10mins at EOL.

Allows for power factor and a bit load increase as the motor ages.

I would be looking at the following Suppliers: -

• THYCON
• Chloride

as they do UPSs for industry rather than Just IT environments.
Please Note: These are just suppliers I have worked with in my area. There may be other alternatives closer to your location

Regards,
Sapper

The best UPS manufactures are MGE; SOCOMEC; GE and Emerson. You can ask for the Industrial application UPS with statice bypass.

Best Regards,

MVK

Dear MVK,

I would disagree with you Chloride is a leader in the ups industry in Europe and has a world wide service organization. They build ups up to 750kva and up to 8 can be parallel to power a 6MVA site. Their software can link multiple ups together from different facilities world wide.

MVK,

I agree with your comment for Industrial IT applications, but for Industrial Plant applications I would select Thycon, Chloride or GE over all of the rest you have mentioned, although I would argue "Best", but they are good in thier own rights.

Thycon, Chloride and GE all provide Hardened UPSs to support places like Oil Rig, Mines etc, I have not heard any comments (good or bad) about the others in these applications which is a good indicator that they are not the predominant UPSs used in this type of application.

Regards,
Sapper

Hello aikhh,

I am not sure how many motors you can drive from an UPS. However I list a site below which can give details of the UPS you mentioned. See below.

http://www.google.co.uk/search?hl=en&client=firefox-a&rls=org.mozilla:en-GB:official&hs=iWX&ei=IDKiSoKfJYmh4gb_saDvCQ&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=UPS+sizing+for+415V+3+phase+50Hz&spell=1

Keep in touch and let me know how you get on, OK?

Take care and good luck.

Hi, all of our collegues gave good ideas. definitley they are right.

I suggest a simple calculation to understand how to perform the sizing of UPS.

1. Identify the load requirement: For example 3 KW (only one motor)

2. PF at which it operates to get KVA: (taking PF 0.8) 3.75 KVA.

3. Take 10% excess : 4.125 KVA Round figure to 5 KVA. (3 phase UPS)

4. Please be aware with this UPS you cannot restart the motor but it maintains the running load.

5. Now coming to the battery bank. As you require hold up time of 10 min; specify the same to UPS vendor.

Hello imandi007,

GA to you Sir.

I worked this out for all the integral electric of my computer. It needs a much smaller UPS of course I got a 12 watt just to be on the safe side. I get 15 minutes. For the cost of an UPS to power more than one motor, it would be cheaper to get a Generator? A Generator is much more versatile as well.

Take care.

Hi imandi007,

Thank you very much of your info

Regards

all the comments so far are on target but you may also want to consider a back-up generator. The question is whether your production line can wait for the few seconds for the generator to start and come on line.

If that time will not allow for a preheat then choose a gen that starts direct. This should give you power in less than 20 seconds, and then for as long as there is fuel in the tank.

It is also possible to have a combination of both systems. the UPS for low power control circuits and the gen for the motor devices.

Chas

Hello capblanc,

I answered direct from my notification from the post which had one GA. I did not realise you had suggested a generator also, sorry.

Take care

Hi Aikhh,

In addition to what Sapper has said when you are refering to max amps - that should be the lock rotor amps or inrush current that occurs at start up. The ups overload capaiblities must be able to handle the start up current or the ups will switch to the bypass mode or shut down.