Servo stabiliser in combination with Online UPS - advice needed

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Fiftyfifty

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Hi!
I currently have a dedicated phase from my distribution board going into my 3 kva dual conversion online UPS which feeds my audio setup. The other 2 phases are distributed over the apartment. I now wish to install a 25 kva servo stabiliser that will provide stable supply to the entire apartment, including all ACs, white goods, lights and fans.
The dealer has advised that all 3 mains phases should feed the 3 phase servo stabiliser, which will then output 3 phases of stabilised supply. One of these phases can directly feed the online UPS for the audio setup, while the other 2 phases will take care of all other needs via the DB box in the apartment. This would mean that the power supply to my audio supply would go through a 2 stage stabilisation, first by the servo and then by the UPS. The perceived advantage is that the audio setup would get stabilised supply even if either the servo or UPS fail. My concern is that the servo stabiliser may interfere with the pure sine wave or introduce any other kind of noise in the line. I now have the following options:
1. As advised by the dealer above
2. As above, let all 3 phases pass through the servo, but set one phase that goes to the UPS on bypass mode. I am afraid that this too would introduce some interference due to dynamic balancing and components in the servo stabiliser.
3. Supply one phase directly to the online UPS + Get 2 x 10 kva single phase servo stabilisers for the remaining 2 phases for the rest of the apartment needs (2 phase stabilisers are not available). This way my audio setup gets power from the mains without passing through the servo stabiliser. The downside of this option is that I have no backup for my music system when the online UPS fails.

There is not too much difference in the overall cost of the 3 options. Please advise what would be best from the sound quality point of view.

Many thanks
 

raghupb

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25KVA. What is the sanctioned load for your apartment?
Normally it would be between 5-7 KVA for the entire unit.

Cheers,
Raghu
 

Fiftyfifty

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25KVA. What is the sanctioned load for your apartment?
Normally it would be between 5-7 KVA for the entire unit.

Cheers,
Raghu
Hi,

Thanks for responding. Keeping the capacity of the unit aside for the time being, can you comment on the sequence of connections please.

Cheers!
 

raghupb

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This is what I think.
- Servo (3 phase) followed by UPS (Audio)
Here voltage stabilization happens at supply side of UPS. Which is good because UPS (in mains mode) doesn't have to stabilize anything really.
In backup mode, the servo is out of the picture and UPS generates the "sine-wave"

- UPS (for lighting circuit) followed by Servo (1-phase for audio)
Here UPS may do some amount of stabilization (if supported) followed by servo stabilization.
In back up mode, the servo will actually help is battery is undercharged (leading to voltage sag)

In both cases, I doubt whether servo stabilizer does anything to the sine-wave.
Noise wise, it depends on how well stabilizer is designed.

If budget is not an issue, 3-phase Servo at supply side followed by UPS for lighting circuit (or for dedicated audio circuit) is a good plan.
Some rewiring at Load Distribution Box may be required.

Edit:
If doing 3-phase servo, I'd go with 1.2-1.3x sanctioned load capacity.

Cheers,
Raghu
 
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drkrack

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This is what I think.
- Servo (3 phase) followed by UPS (Audio)
Here voltage stabilization happens at supply side of UPS. Which is good because UPS (in mains mode) doesn't have to stabilize anything really.
In backup mode, the servo is out of the picture and UPS generates the "sine-wave"
I have this connection with 5kva Stabilizer and 3.5kva Online, Sine wave UPS. This is the recommended connection hierarchy.
Recently I bypassed the UPS for HT, Connecting to the Direct Stabilizer Connection, Couldn't find any difference in SQ. Pushed the UPS to AVR and Projector.
@Fiftyfifty, if it's not absolutely must you can skimp on UPS. With the higher Capacity under consideration , I can't be very sure about the final noise levels ( 25kva UPS will be noisy), consulting a technical expertise locally would be a better idea.
 
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Fiftyfifty

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I have this connection with 5kva Stabilizer and 3.5kva Online, Sine wave UPS. This is the recommended connection hierarchy.
Recently I bypassed the UPS for HT, Connecting to the Direct Stabilizer Connection, Couldn't find any difference in SQ. Pushed the UPS to AVR and Projector.
@Fiftyfifty, if it's not absolutely must you can skimp on UPS. With the higher Capacity under consideration , I can't be very sure about the final noise levels ( 25kva UPS will be noisy), consulting a technical expertise locally would be a better idea
Online UPS for audio and 2 servos for the other 2 phases may be the best solution?
 

sud98

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I think what the dealer said would work, although its a waste of some energy. Try and make sure both units are outside the house and at the place where the distribution box is placed as they are both super noisy.

Rated capacity of servo should be some 20% higher than your house rated capacity. So unless your house is rated at 20KVA, 25KVA is an overkill.

The 3rd option would also work but having three such devices is a pain IMO.
 

Fiftyfifty

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Given the current technology, I would be more confident of a dual conversion online ups than a servo to provide clean power. Hence the third option appeals the most to me
 
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