Subbu68
Well-Known Member
You have two more MOVs there?? Hence, my doubt.Ha ha. Those were connections going to 3 leds. The el cheapo that I am, I salvaged the leds from that board and used them elsewhere
UPS/Power conditioner for HIFI systems?
- Thread starter SuyashMoorpana
- Start date
Those are Y capacitors. The mov became carbon.
Subbu68
Well-Known Member
Poor MOVs
Their larger bros on the power system too undergo the same trauma. they have much more muscles so they survive but sometimes shatter into pieces.
Subbu sir, i understand that ups output is never perfect sine wave but what about constant minor fluctuations in voltages in home supplies and frequent power outages leading to voltage fluctuations and premature equipment failure. Is there any solution better than an online ups for these problems ?As an electrical engineer I can only say none of the so called pure sine wave commercial 1 phase UPS can provide you a pure sinewave as even a small kerosene engine driven genset can. They don't turn in a magnetic field like an AC generator in a perfect circle to produce a sine wave. All of them chop the DC and serve a chowmein of harmonics whatever filter they use.
Unless you have a 3 phase isolation transformer with delta connected primary and star secondary you are not going to eliminate fully the harmonics generated by the chowmein supply feeding into your gear. And for that you need a 3 phase UPS.
And those poor transformers inside are designed to work on 50Hz will have to gulp down 100, 150, 200, 250, 300 Hz etc. at differing "strengths" and get "drunk", get hot and die a premature death due to many kinds of electrical cancers - insulation failure, internal shorts, core over heating, winding failures etc. etc.So I don't think these pure sine wave are the holy grail.
Always a stable network power is the best sine wave you can get. The generation behind your "disgusting" EB power is in GWs (In India something like 300 Giga Watt so where is your 200Wpc amp?). It is an infinite bus.
The surges you experience is many a times beyond the control of any power utility - mostly lightning or fault induced or by your neighboring workshop doing welding or a furnace in the industrial park throwing load up and down.
For these surges as @mbhangui explained or @ranojoy pointed out you need a proper surge protection. Or you'd have "fryums" made of capacitors, resistors and chips on your AV rack. Stabilisers may not act fast enough to tame these surges. They can't as unless there is a steady state rise in voltage these deviations may be in their deadband. dv/dt has to match the inertia they have.
You also cannot purchase any power strip and assume it will not get fried. These lightning surges though last only a few micro seconds the energy is unbelievable and so too the effects may be benign or devastating.
The power strip should be able to take in the energy so you need to choose as high as possible in the order of 1kJ. Once the MOV is fried and open, the surges have free access to lick your gear with their fire.
You also need to look for a 3 line protection - Line to Earth, Line to Neutral and Neutral to Earth.
I was eyewitness to a lightning bolt getting to the ground two times - once through a 50m lightning mast and another through a ground wire up a 400kV power lines. Beautiful sight but we had no cameras or mobile phones those days to record
The first review on Amazon.in page for belkin surge protectors.
Subbu68
Well-Known Member
Hi
These are surge protectors that act on fast wavefronts in general. They also have a clamping voltage rating usually in the order of 400V to 750V depending on what MOV is chosen. Any 240V rated equipment, especially electronics will not withstand long term overvoltages. The usual fluctuations on the network will be lower than this Belkin kind of surge protectors' threshold and they would not do their job. For these fluctuations definitely a stabilizer is the solution. Maybe very fast acting thyristor controlled ones.
As @keith_correa said you need a O/V and U/V cutoff relays. I have seen these in older stabilizer on my mom's fridge. Should be there in all.
Online UPS by virtue of their working principle should not bring these fluctuations to the load as they convert any AC that is fed in to DC before inverting to AC.
Having lived nearly quarter century in a place with excellent voltage regulation it is difficult for me to say more about the practicality of UPS, surge protectors and stabilizer. Happy to learn more from real life experiences you all have in India. Ultimately I may have to settle somewhere there.
Not that we are in heaven
. We have had an incident where nearly 400 electricity meters got fried due to voltage rise - that was due to very low loading of network, Ferranti effect of MV cables and distribution transformers at regular tap. The area developer to blame - no takers for buildings so no load on network.
ankitbhargava
Well-Known Member
Am a Victim of exactly same situation and have lost multiple AV equipment. All of them had failed Power or Main Boards.
Unfortunately the Servo Stab also could not do the job in last 2 instances the equipment failed.
Have you found out any better solution than a online double conversion ups ?
ankitbhargava
Well-Known Member
I am also looking for better solution, I have been recommended Online UPS (double conversion) with built in Isolation Transformer. FM @Love4sound has found it the best solution.
lingamkrishnan
Active Member
I have bought Luminous 2kva online UPS with built in Isolation Transformer which is connected to 3kva Servo Stabilizer.
the output the UPS gives power to my entire media room except lights and AC.
sud98
Well-Known Member
I dont think the servo is adding any value here as the UPS will be doing the double conversion as well as the EMI/RFI filters and will give better surge protection than the stabilizer.
ankitbhargava
Well-Known Member
I got a dedicated SPD and also EMI/RF filter added to this Krykard Servo Stab I have, I was avoiding to have the UPS changed.
Based on suggestions, I am looking at Online double conversion UPS now. Use cases of @lingamkrishnan and @Love4sound , they resolved their power issues by using Isolation Transformer.
lingamkrishnan
Active Member
you are right, servo doesn't do any job here as UPS will take care of backup and voltage surge protection. This servo was bought initially at the time of my HT setup and UPS was very recent addition, I din't want to keep servo idle so added into my power chain.
lingamkrishnan
Active Member
Yes ankit, now i peacefully use my HT without any fear. My apartment had many cases of voltage fluctuation where many electronic devices, stabs got damaged. Though we have automatic generator, Sometimes maintenance team put the DG in manual mode which they will wait for E.B power around 30mins but during that period my 2kva ups gives full backup.
Love4sound
Well-Known Member
I only use an isolation transformer in my chain. Don’t have any ups or voltage stabilizer. I sold my vertex servo stabilizer. In my experience it is of no use. It’s a top recommendation in the forum but in the event of faults it isn’t effective. Only helps with stable voltage and cutoff.
When using an online double conversion ups imho, the cycle is mains ac ->dc in battery -> regenerated ac, so this double conversion is already protecting against mains ac spikes and voltage fluctuations as the output is regenerated ac so what's the use of an isolation transformer here ?
I agree if not using an online double conversion ups then second best is stand alone isolation transformer, but after a double conversion ups the isolation transformer seems to be of little use if any.
While we talked a lot about voltage fluctuations and spike but has anyone noticed that earth pin is always direct wheather it's an isolation transformer or online ups. The earth wire (if not properly earthed, if somehow shorted to phase wire, this could potentially lead to mess.
I agree if not using an online double conversion ups then second best is stand alone isolation transformer, but after a double conversion ups the isolation transformer seems to be of little use if any.
While we talked a lot about voltage fluctuations and spike but has anyone noticed that earth pin is always direct wheather it's an isolation transformer or online ups. The earth wire (if not properly earthed, if somehow shorted to phase wire, this could potentially lead to mess.
Love4sound
Well-Known Member
Can an online double conversion ups give protection against neutral faults and DC or AC leakage from other devices?
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sud98
Well-Known Member
I know it has emi/rfi filters for ac leakages. Not sure of neutral faults.
Love4sound
Well-Known Member
As far as I know it doesn’t. Also it doesn’t block any DC leakage. That’s why there is an inclusion of isolation transformer.
ankitbhargava
Well-Known Member
Based on experience and kind advise of @lingamkrishnan @Love4sound , I have installed Luminous LB3000T double conversion Online UPS with Isolation Transformer. Can not risk my peace of mind and equipment anymore. I hope this brings end to the recurring problem of blowing up my equipment.
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