# SMPS doesn't power on when connected directly to UPS but does with Surge Protector in between



## mandarpalshikar (Oct 22, 2013)

I have a APC Back-UPS RS 1500 and Corsair AX850 in my rig. Yesterday I noticed that when I connected the power supply cable directly to UPS, it doesn't power on. But when I connect a Belkin Surge Protector to UPS and then connect SMPS cable to surge protector, it does start.
Why would this be happening. I don't want to use surge protector with UPS as it is not recommended.


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## quad_core (Oct 22, 2013)

I have read that some corsair PSUs have issues when connected to APC ups. Will check on it further .


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## bssunilreddy (Oct 22, 2013)

Taken from Tom's Hardware forums:
Actually APFC circuits in any PSU are susceptible to non-sine wave that generated by backup UPS..

If you use it for a long time, it will damage your PSU apfc circuit,
in other word, 
will damage your PSU... *m.bestofmedia.com/sfp/images/design/usr/smilies/smile.gif 

But, will it work..?
Yes..

but don't use it for a long time (more than 5 minutes)..

Main purpose of backup UPS  just to give you time to save your work and shut down the computer...      
Corsair recommends a Pure Sine Wave UPS with their PSU's.  
Any UPS over 1000VA in our SMART-PRO and SMART-ONLINE series will offer the pure sine wave output these aPFC devices require.


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## kARTechnology (Oct 22, 2013)

bavusani said:


> Taken from Tom's Hardware forums:
> Actually APFC circuits in any PSU are susceptible to non-sine wave that generated by backup UPS..
> 
> If you use it for a long time, it will damage your PSU apfc circuit,
> ...



apc sinewave new models they cost 8K if taxes added and you can get a inverter with nearly 10hrs+ backup depending on load(get a cheapo tubular 80ah battery, apc ups has 2 7.2ah's so 14.4ah<80ah) with that price by adding 2k


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## mandarpalshikar (Oct 22, 2013)

^^ In case you didn't go through my full post, I already own a APC Backu UPS RS-1500, which costed me 13k back in Jan'13. So there is no question of changing it now.
And the issue is PSU doesn't power on at all when directly connected to UPS. But when I connect PSU through a surge protector which is getting power from UPS, then PSU powers on. 

@havoknation - whts ur opinion? I bought both the PSU and UPS from you.


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## havoknation (Oct 22, 2013)

mandarpalshikar said:


> ^^ In case you didn't go through my full post, I already own a APC Backu UPS RS-1500, which costed me 13k back in Jan'13. So there is no question of changing it now.
> And the issue is PSU doesn't power on at all when directly connected to UPS. But when I connect PSU through a surge protector which is getting power from UPS, then PSU powers on.
> 
> @havoknation - whts ur opinion? I bought both the PSU and UPS from you.



I have heard APC has a good onsite support. Kindly raise a ticket with them and let them check first.

Also do let us know whether this issue are you facing from day 1 or just now?


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## mandarpalshikar (Oct 22, 2013)

havoknation said:


> I have heard APC has a good onsite support. Kindly raise a ticket with them and let them check first.
> 
> Also do let us know whether this issue are you facing from day 1 or just now?



Yup... gr8 idea. I'll call them tomorrow first thing in morning.

I never connected my PSU directly to the UPS before   Always had an Belkin extension box / surge protector in between.


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## maheshn (Oct 23, 2013)

bavusani said:


> Taken from Tom's Hardware forums:
> Actually APFC circuits in any PSU are susceptible to non-sine wave that generated by backup UPS..
> 
> Corsair recommends a Pure Sine Wave UPS with their PSU's.
> ...




...look around for Electronics experts/publications and you will find that there is *NO* UPS with true "sine wave" output which duplicates an AC waveform exactly. All of them give at best an approximation, and at worst a square wave which will damage any equipment (not only SMPS) over a period of time. Some UPS's give much better output than others, so the only thing to do is take a very good look around before buying anything. That said, some particular series of SMPS don't play well with some particular UPS also. Caveat Emptor - Let the buyer beware


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## whitestar_999 (Oct 23, 2013)

> I never connected my PSU directly to the UPS before Always had an Belkin extension box / surge protector in between.


i think using this setup for a long time has damaged some controller/regulator circuit of your psu resulting in it being incapable to operate directly from ups as surge protector kind of acts like a filter.i may be wrong but for future keep in mind that surge protectors are not some one stop solution & will fail in an event of extremely high voltage/current like lightning strike unless main power junction of your home is properly grounded.in my opinion using surge protectors with desktop is pointless & in wrong setup maybe even harmful.


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## mandarpalshikar (Oct 23, 2013)

whitestar_999 said:


> i think using this setup for a long time has *damaged some controller/regulator circuit of your psu resulting in it being incapable to operate directly from ups* as surge protector kind of acts like a filter.i may be wrong but for future keep in mind that surge protectors are not some one stop solution & will fail in an event of extremely high voltage/current like lightning strike unless main power junction of your home is properly grounded.in my opinion using surge protectors with desktop is pointless & in wrong setup maybe even harmful.



??? Didn't understand this.... there is no way PSU can know whether power is coming directly or indirectly from UPS during normal operations with home power on. Yes there would be difference when running on UPS battery backup. But those instances during last 6 months have been only 3 or 4 times that too only for 5 mins maximum each. This PSU has been tested at my friends place for aprox a month and it did not get into any issues. So I'm sure PSU is not damaged at all.

My main purpose of using Surge protection was using it as good quality extension box for cables since normal extension boxes available in market are usually of very bad quality.


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## whitestar_999 (Oct 23, 2013)

without going into much details here is the simplest explanation.UPS does not clean/filter power.it merely passes on the AC power from mains to PSU.PSU then convert this power to DC by making it dirtier & then cleans it accordingly for pc use.when mains power is off ups is running on batteries which already produce dirty DC power which is in fact more suitable for psu.when you place a surge protector in between that changes things.when mains power is on it will work but when mains power is off & ups is running on batteries supplying "dirty" power it will look like many small variations to surge protector kicking it into action kind of acting like a filter which will result in modification of otherwise suitable power for psu.

P.S.not every device needs a gold plated thousands of hour tested perfectly insulated cable.get any decent extension box giving 6-12months of warranty(in my area i got for ~120) & you are good to go for whatever usual home appliance you can possibly think of.all that matters is the current rating in Ampere & my Rs.120 box has 6A rating & only a split ac will require more current than this in a home.


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## mandarpalshikar (Oct 23, 2013)

whitestar_999 said:


> without going into much details here is the simplest explanation.UPS does not clean/filter power.it merely passes on the AC power from mains to PSU.PSU then convert this power to DC by making it dirtier & then cleans it accordingly for pc use.when mains power is off ups is running on batteries which already produce dirty DC power which is in fact more suitable for psu.when you place a surge protector in between that changes things.when mains power is on it will work but when mains power is off & ups is running on batteries supplying "dirty" power it will look like many small variations to surge protector kicking it into action kind of acting like a filter which will result in modification of otherwise suitable power for psu.
> 
> P.S.not every device needs a gold plated thousands of hour tested perfectly insulated cable.get any decent extension box giving 6-12months of warranty(in my area i got for ~120) & you are good to go for whatever usual home appliance you can possibly think of.all that matters is the current rating in Ampere & my Rs.120 box has 6A rating & only a split ac will require more current than this in a home.



Got it... I'll try with an extension box today if the PSU powers on with it or not.


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## quad_core (Oct 23, 2013)

Hi whitestar ,
Sorry for hijacking this thread.. I have a query on the same lines, hence thought its probably right thread to post my query. I have just bought a new PSU which is Corsair tx750. We also have recently installed Luminous sine wave inverter with a large battery. It costed almost 35k. The switch board to which the PC is connected is connected to inverter . How safe is it to run my PC this way? I shut down the PC immediately after main power goes off. ( I use on inverter just for 5 mins max)


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## whitestar_999 (Oct 23, 2013)

there should be no problems but personally i prefer UPS although most modern home inverters also have a inverter/ups switch at the back.the only issue regarding this setup is that there is a chance of home ups overloading if it is connected to too many running home appliances at the time of power cut but if not then no issues.


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## quad_core (Oct 24, 2013)

Thanks for clearing the doubt .


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## kARTechnology (Oct 24, 2013)

quad_core said:


> Hi whitestar ,
> Sorry for hijacking this thread.. I have a query on the same lines, hence thought its probably right thread to post my query. I have just bought a new PSU which is Corsair tx750. We also have recently installed Luminous sine wave inverter with a large battery. It costed almost 35k. The switch board to which the PC is connected is connected to inverter . How safe is it to run my PC this way? I shut down the PC immediately after main power goes off. ( I use on inverter just for 5 mins max)



no problem with the inverter set in "ups" mode in back and you can run the pc as long as you want as the power output of inverter is clean as grid poewer/utility power

i run my pc for nearly 10 hrs on a sinewave inverter.... no issues


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## mandarpalshikar (Oct 31, 2013)

Here is what I got from APC forums _-------------
Ok, here is some additional information that I obtained.

There certainly are PSUs out there that do not like Step Approximation as it is generated through solid state components, as opposed to natural generation. We have begun to develop some smaller units with a quasi sinewave output, which is much closer in size and quality to a pure sinewave, however this modification has not yet reached the -IN product families.

Regardless, the initial description of events when connecting your PSU seem odd. If the PSU is not powering on when the UPS is online, it's possible the inrush of the device is causing an Online Overload condition.The addition of the surge strip is potentially limited this inrush, in turn allowing the PSU to power up without triggering the Online Overload. Just a guess based on what you've said so far but beyond that, we cannot think of any other reason for this strange observation.


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## whitestar_999 (Oct 31, 2013)

did you tried using extension box without surge protector?


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## mandarpalshikar (Nov 2, 2013)

whitestar_999 said:


> did you tried using extension box without surge protector?



Will be buying one this weekend.



whitestar_999 said:


> did you tried using extension box without surge protector?



PSU started with a local made 6 amp 100 Rs extension panel.


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