Is Your MOV-based Surge Protector Still Working?
Jack Burlin responded to my recent editorial in Processor Magazine. His feedback was very interesting... I thought others might feel so as well. He reminds us that if the light on your surge protector is off, the MOV component used to shunt high voltage spikes to ground might be dead and no longer protecting your equipment.
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Bill:
I enjoyed your article in the January 19 issue of processor. Your discussion of VA compared to Watts was interesting, so I did some checking.
Here is the link to the UPS portal page on our website:
http://www.iscdfw.com/onlinecatalog/powerstrips/ups/ups_main_menu.htm
If you look under the descriptions on the Enterprise series UPSs, you will see that the VA - Watts correction factor is .60, just like you said in your article. However, if you look at the descriptions of the CPE series you will see the VA - Watts correction factor is .70!
You might also like to look at the newsletter article I wrote on surge protection and MOVs. Here is the link:
http://www.iscdfw.com/newsletters/2006%20Newsletters/February06/February06.htm
The reasons VA and Watts are not equivalent in a UPS are many. The primary reasons are that UPSs are not 100% efficient. There is a Power Factor that needs to be figured in to calculate the amount of Watts that can be delivered by a certain level of VA entering the UPS. Most of the difference is Power Factor error, but not all. When UPSs are more efficient, the loss due to Power Factor decreases. This is what our two different series of UPSs is saying to us in the above example. The CPE series is newer technology, and the efficiency is higher.
Another source of loss is the fact that the UPS takes power to operate. It has its own internal electronics and there is a loss associated with things like automatic voltage regulation and the like. Likewise, the batteries are constantly being recharged if they should ever momentarily fall below the appropriate level. This bleeding off of power in order to operate the UPS is another major reason that the output is less than the VA input would lead you to believe.
If you have any questions, please give me a call. By the way, if you need networking products for your business, we can be an excellent resource for you.
Thanks,
Jack Burlin
Product Manager
Information Support Concepts, Inc.
Certified Woman Owned Small Business Enterprise (WBE)