Electrical surge issue

<....clearly specifies that UPS had failed to cut-off the surge voltage....Is there any possiblity of surge voltage from ups due to malfunctioning....>

Evidently there is!

Q1: Is the UPS itself damaged?

Q2: Is anything upstream of the UPS damaged?

These questions should help identify the location of the problem.

Surge protection outlets may be found at most electrical equipment retailers these days. In this particular case, the potential investment might seem to outweigh the cost of the risk.

A1: No the UPS haven't got damaged...

A2: No, the damage was only at down stream...

Q3: Is the UPS still under the manufacturer's Warranty?

[Premise: A customer who complains is doing a business a favour, as compared to the ten customers that don't and take their business elsewhere.]

• If so, then get a replacement on warranty. If the UPS supplier doesn't play ball, threaten to blog and/or contact your favourite customer service investigation television programme to describe what you have experienced. Invest in surge suppressor outlets downstream
• If not then after discussing it with and giving the supplier an appropriate period of opportunity to put it right as a gesture of business goodwill (you are an important and valued customer, they said in their correspondence!) invest in a replacement from a more reputable manufacturer, invest in surge suppressor outlets and threaten to blog and/or contact your favourite customer service investigation television programme. Do they want the old one back for recycling?

Bluff is a valuable 'soft tool'!

Observation: Why are the fax machines on the UPS? Most unusual!

The fact that is was modems and fax machines may be a clue. Perhaps the surge/spike came down the phone line, not via the mains voltage/UPS? Just a thought.....

Tom

Is neutral is derived at UPS? Did you check the neutral to ground voltage ( <2V). The neutral may be loose somewhere at down stream and also we may have to check till UPS transformer. If neutral is loose then UPS/TVSS will not identify the fault.

Trasient voltage surge suppressors are avialable with all branded manufacturers.

Lots of good answers and bravo to Hara143 for thinking globally. I'd offer the following questions that need to be answered (and some of them aren't easy to answer):

1. you speak of a surge - what was it? How do you know of it? That's a key point - what was the disturbance?

2. The UPS ONLY protects stuff plugged into its power circuit, but the UPS itself depends on everything else being cool - proper (low-impedance) grounding, proper neutral connections at your supply source, etc. etc. Also UPS have wide-ranging specs & capabilities in terms of what they can cope with.

3. Not the same point but obviously related to #2: is the UPS wired/installed correctly?

4. as already mentioned: could the surge have come in another route? Just to get you thinking: not just phone lines etc, but are pieces of equipment plugged into the UPS connected to stuff that isn't (a typical killer)?

All this to say: maybe it's a bad UPS, but it could also be other problems..ain't easy.

Nice weekend

rfg

Hi all, thanks for ur inputs...

Wish to clarrify the following:

• On checking N-E value it's well within 2V
• The impact was like, 3 monitors got burnt and on investigating other equipments like CPU, Fax m/c (as there is no raw ower socket available near b, fax m/c is connected with ups) modems etc., the smps & power cards had got flashed over.
• I hope so that the ups has been installed & wired properly because it was all done by the manufacturer himself.
• Moreover we have got one more ups exclusively for server (APC make) which haven't got affected.
• what could be the possiblities of other routes of surge??

Check the condition of the UPS batteries.

The APC UPS is not designed to handle loads from Printers and faxes. These loads draw large spikes of current quickly. The rectifiers cant keep up with the inverters and hit the batteries to get the extra energy

I am aware of a similar instance several years ago. These guys were having issues on a regular basis. They put a scope on the output of the UPS and were seeing spikes. They removed the UPS from the circuit and the problems went away. They started checking out the UPS and discovered batteries were bulging all over. The replace the batteries and the problems went away.

I can't explain electrically why bad batteries would spike the output but its worth checking out.

Good luck

Its quite simple, in some, not all, UPS systems, the batteries work rather more like a giant capacitor than a true battery. If the Battery is defective (bad cap) then spikes can get passed through....

Quite often Lead acid batteries go high resistance when they fail. They have lost their "capacitance"....

There are only two probabilities:

A. The Joule rating on the UPS is too low. There are two possibilities herein: Exceeding the joule rating will clamp the protective circuit and temporarily defeat all protection. or Exceeding the joule rating destroys the circuit and pernamently defeats the protection. A reliable UPS will be equipped with red, green, and yellow LED status indicators that display either condition

B. The excessive joule surge originates downstream ie on the outlet side or supply side of the UPS. Unlike common perception, the source of the excessive joule surge does not occur by switching a large load "on" but rather does occur by switching or dropping "OFF" a significant load on the UPS supply side. For example, a large HVAC fan or A/C plugged into the UPS supply side will result in a destructive joule surge to PCU and/or other sensitive equipment when the HVAC device is switched "OFF" or unplugged

Obviously, you should be able to determine and readily verify which of these conditions exist in your installation.

I infer from the discussion that the problem occurred when the office was not in use. This could also suggest that someone unintentionally caused it, such as a cleaning person using the UPS power as a convenient point to attach a vacuum or floor polisher.

There are many ways to reduce or eliminate voltage spikes, with the most common one being MOV's (Metal Oxide Varistors), which arre cheap and readily available. I don't trust the electronics in TVSS receptacles, and MOV's are available in many ratings. The problem with MOV's is that they must be chosen with voltage levels safely above the peak voltage of the sine wave, and they can be fried when the joule surge is too great (as was well-said in the posts).

A number of products are in the market, which are a power strip containing two or even three modes of surge suppression, including suppression for telephone or data lines. Some of them have warranties which extend to the equipment attached, providing repair or replacement at no materials cost to the user. This approach may be worth investigating.

--JMM

All good answers so far. I suspect the bulging batteries were "open" internally so the filter or capacitor effect they normally provide was lost and surges passed through. 1000 volt spikes in distribution systems are not uncommon and typical house wiring will limit lightning to 6000 volts due to spacing of terminals and insulation breakdown.

I solved a similar problem by moving inter-building UPS wiring underground.

A good read on what is what with surges http://brickwall.com/conditn.htm

tdesmit #4

For Modem & Fax M/C it is true. I have the experience of getting my Modem almost flashed over to its DC I/P pionts of PCI connector while not only power switch was off, but also plug taken out but telephone-line connected.

It also flashed-over the phone.

hara143 #5 [neutral]

Q4. Is the UPS 3Ph ?

Nuertral may surely create problem [at any time; not only at Lightning]

Had the neutral been loose [or open or intermittently open due to looseness], load of each 2 phases will come in series. The heavier load will be safe while the lighter load will have much higher voltage in its share.

By simple ohms law. lower load means Hi restance; while heavy load have relatively lower resistance.

In series Hi R will have higher than normal supply & items will start burning one by one. as 1 item is off due to damage the left-overs will rapidly start going to heavens one after the other.

This is the story for 1 set of 2phases connected in series; while all loads are connected to other. R+S S+T & T+S phases combination.

All the heavier load will be protected, if the fault is timely removed.

Otherwise there is a chance that heavier than the heavy one is switched-in & the heavy-one becomes the lighter.

dda #10

Almost all the manufacturers mention about the printers od certain type can run or nor in the User' guide. And it is not for a specific maufacturer of printer but in common to all.

semi-retired designer #11

<< I suspect the bulging batteries were "open" internally so the filter or capacitor effect they normally provide was lost and surges passed through.>>

A good batteriy have an infinite CAPACITANCE & can limit surges across it to its capacity.

Of cource if batteries are OPEN or at the end of-life, the "CAPACITIVE" effect is minimum, & rectifier's surges may pass-through.

A large Filter capacitors bank is connected after rectifier.

The "INVERTER" is the next to be on stakes if by anyway surge gets thru.

UPS is not damaged as the user explains.