The end of life of UPS

[Yokohama]

Dear,
We are planning to replace UPS with new one. Current using
UPS is 200KVA and 17 years old.
Japanease UPS manufacturer recomended to replace for the safety since over 15 years.
I would like to know UPS`s the end of life time in Europe & US except batteries`s the end of life.
How long is the life time of UPS?
How should we consider about UPS main unit with double conversion type?
Would you please advise me?

Best regards,

 

[dbaird]

Check out:
ftp://

http://www.apcmedia.com/salestools/VAVR-5W5PF5_R0_EN.pdf

David Baird
mrbaird@hotmail.com

Sr Controls Engineer

EET degree.

Journeyman Electrician.

 

[alehman]

I know of several system older than this that are still in operation. Key factors in the replacement decision are history of reliability, availability and cost of replacement parts and knowlegeable service technicians.

Double conversion remains the technology of choice in that size range, although a few manufacturers (e.g. APC) are promoting other systems.

 

[jraef]

Generally the life expectancy of electronic systems goes down at a logarithmic rate as they age, so the older it is the faster it is deteriorating. This is not automatically a concern as long as it is working, so old electronic systems can be found in any application and environment. The problem with older UPS systems however is the nature of the application itself. In general, you do NOT use it unless you already have a failure of some other system. The entire reason that you have the UPS is as a backup (redundant) source for power. If an older system was working fine when tested, but the strain of needing to perform after a power failure is too much for it and it dies at that critical moment, then the entire reason for it's existance became a colossal waste of resources. So as a UPS gets older, the risk of it's failure looms greater as a critical issue. 10 years of service is considered a good cost/risk compromise. 15 years would be significantly better cost wise but also significantly riskier so most consultants would suggest replacement.

"Venditori de oleum-vipera non vigere excordis populi"

 

[alehman]

The concern mentioned in the previous post that "you do NOT use it unless you already have a failure of some other system" is precisely the advantage of double conversion systems.

The inverter of a double conversion system supplies the load at all times whether the load is supported by utility power or by stored energy. Other systems rely on fast switching of the load from utility to an alternate source when the utility fails. Obviously the batteries are a possible point of failure with either system.

 

[busbar]

I would regard a salesman’s suggestion of “replace for the safety since over 15 years” as suspect, self-serving and having no concern for you as a client except to generate a fat purchase order.

Have maintenance/repair expenses increased significantly or reliability appreciably dropped? These seem like they would be far more valid reasons to consider replacement.

 

[jbartos]

Suggestions to the original posting marked ///\\We are planning to replace UPS with new one. Current using
UPS is 200KVA and 17 years old.
Japanease UPS manufacturer recomended to replace for the safety since over 15 years.
I would like to know UPS`s the end of life time in Europe & US except batteries`s the end of life.
///The manufacturer is approximately correct. The off the shelf VFDs from ABB have approximately 53000hrs MTBF. This would be close to 15years.\\How long is the life time of UPS?
///Since the inverter in UPS is approximately comparable to VFD, 15years of MTBF is reasonable. However, MTBF does not necessarily mean to be used as a criterion for replacement. There are additional factors involved, e.g. UPS application to a process that may result in a costly outage if the UPS fails.\\How should we consider about UPS main unit with double conversion type?
///Because of the double parts count, the MTBF is expected to be lower.\\

 

[alehman]

In response to the previous post, the MTBF would be lower than a single conversion system (VFD to use your example) except for the fact that UPS's are equipped with bypass circuits which automatically transfer the load to utility power in the event of failure. Loss of power to the load therefore requires two simultaneous failures. Manufacturers of double conversion systems typically quote MTBF numbers in millions of hours. That's obviously open to debate, but the point is that there are two parallel paths, both of which must fail before the load is dropped.

 

[jbartos]

Comment: I interpret double conversion type UPSs as AC-DC-AC that separates the AC source from the load.

 

[alehman]

I agree. The bypass circuit I referred to takes the DC link out of the system and connects the load directly to the AC input when called upon.

I agree with jraef in that statistically systems begin to experience more failures once they surpass the 15 year range. I wouldn't necessarily replace equipment of that age unless there are other reasons.

 

[ScottyUK]

On a system of that age, it is almost certainly worth looking at replacement of the components most susceptible to aging - the electrolytic capacitors in the power stages. It is quite probable that the control electronics, power switches, and wound components are in pretty good shape. Electrolytics in the high-current path have a life that is relatively short when compared to the other components. Be careful to choose the replacements carefully with regard to temperature rating, ESR and ESL, and ripple current rating.

If you have no problems with support for the UPS from the manufacturer or a third party, and there has been no degradation of the reliability or increase in component failure rate, there seems little reason to replace the whole unit.




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

Start each new day with a smile.

Get it over with.

 

[jbartos]

Suggestion: Ultimately, electronic specialists in UPS might make an assessment and provide the UPS prognosis.

 

[mta2003]

Dear Yokohama!

As the developement in the field of power electronics is very fast and availability of spare parts of a 15 year or more old equipment is a real problem, therefore replacement of such older equipment is very economical and useful.

God bless.

mta2003

 

[davidbeach]

I'm surprised nobody has mentioned efficiency. Over 15 years the system efficiency of a new system compared to the existing may be great enough to offset a portion of replacement cost.

 

[rbulsara]

IMHO, 15 years is a good number to flag end of useful life of a UPS system, mainly because availability of the parts becomes scarce, in fact such units usually depend on caniibalizing other failed or suplus units elsewhere.

Also the electronic technology and software upgrades changes so much by then that replacement becomes very attractive rather than trying to keep up old unit.

Most UPS system we have 'upgraded' by replacing them were in the range of 15-20 years old.

 

[Yokohama]

Dear all,

Many thanks for your quick answer.
There is many useful answers on this.
I will prepare a comment for these answers.
Would you please give me short term?
I have to consider for your advise.
Sorry for late reply.

Best regards,