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dineshkozhipurath
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Join Date: Jul 2019
Posts: 11

How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/09/2020 8:46 AM

Dear all

we are Facing an issue AC UPS 230V, rectfier float voltage is varying from 383 to 440 generate alarm also.float voltage is 407V then how we can avoid the fluctuation in DC voltage.

which card need to be calibrated or replaced.

LCRD,ALR or LCI
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SolarEagle
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Join Date: Mar 2007
Location: by the beach in Florida
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#1

Re: How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/09/2020 10:12 AM

Let me see if I can decipher this inquiry....This is an AC to DC system, it is fed with 230v incoming and is supposed to generate 407v dc for float charge on a battery bank....the problem is the output dc voltage is fluctuating from 383 - 440 volts, and you want to know what the problem is...? Is this correct?

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dineshkozhipurath
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Join Date: Jul 2019
Posts: 11
#2
In reply to #1

Re: How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/09/2020 11:58 AM

off course,find the details of the UPS for your more ref.

Rectifier type

12 pulse totally controlled

Incoming supply voltage

415 Vac, 3Ph

±10%

Incoming current

262 A

Incoming Frequency

50 Hz

±5%

Floating charge voltage

407.40 Vdc

±10%

1.40 V/El.

Boost charge voltage

451.05 Vdc.

±10%

1.55 V/El..

Manual charge voltage

480.15 Vdc

±10%

1.65 V/El.

Emergency charge voltage

N.A.

±10%

N.A.

Static control tolerance

±1%

Output voltage Ripple

<1% VRMS

Max. Rectifier output current

310A

Battery current limitation on automatic charging mode

60 A

10÷20% C10

20% C

Mounted on

Steel rack

Manufacturer

SAFT

Type

SBM 300

Nos. Of cells

291

Capacity

300Ah / 10h

Charging current

60 A ( 0.15 C10 )

Minimum voltage

311 Vdc (1.07V/Cell)

D.C. input voltage

variation allowed (V)

min. 300 Vdc

max. 480 Vdc

-current absorbed

at minimum d.c. voltage

A 204 A

Rated output voltage (phases no.)

230Vac - 1Ph

Rated output frequency

50Hz

Rated power at cosfì=0.8

70KVA
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redfred
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#3
In reply to #2

Re: How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/09/2020 1:27 PM

Troubleshooting a failing circuit requires an understanding of the circuit topology along with how one obtains data for analysis.

My first suspicion is a capacitor is now breaking down but this could even be as simple as a loose connection.

To troubleshoot this I would use an oscilloscope triggered to display when these low voltage conditions occur on one channel and then look at different parts of the circuit to see what caused it. Possible causes on the input side is the failure of an SCR, IGBT, diode or MOSFET to provide power from one of the three phases. A triggered device might even be getting a a bad trigger. If this voltage drop has no correlation with incoming power phases then a capacitor breakdown or intermittent excessive output load can be the culprit. The output load change might be a battery breakdown, loose battery bank connector, etc.

When was the last time the batteries were independently tested? What battery chemistry?

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dineshkozhipurath
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Posts: 11
#5
In reply to #3

Re: How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/10/2020 12:57 PM

thank you very much

we replaced DC capacitor input capacitor with new one recently , as you said.
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PWSlack
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#7
In reply to #5

Re: How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/11/2020 3:15 AM

What happened as an outcome to that activity?

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SolarEagle
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#4
In reply to #2

Re: How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/09/2020 4:59 PM

Redfred is right, you need a troubleshooter to trace out the problem with proper testing....the first thing I would do would be a visual inspection and have an infrared temperature tester, check for discoloration, swollen capacitors or hot spots...

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PWSlack
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#6
In reply to #2

Re: How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/11/2020 3:15 AM

What was the outcome of the phone calls made to <...SAFT...>?

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HiTekRedNek
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#8
In reply to #2

Re: How Do I Fix the Rectifier Voltage Fluctuation in CEG AC UPS?

05/11/2020 7:47 AM

The voltages specified are plus or minus 10%,and your measurements are within this range.

Adjust alarm trigger points accordingly.

Incoming supply voltage

415 Vac, 3Ph ( 456 -373 vac)

±10%

Incoming current

262 A

Incoming Frequency

50 Hz

±5%

Floating charge voltage

407.40 Vdc (448-336Vdc)

±10%

1.40 V/El.

Boost charge voltage

451.05 Vdc.(496.2-405.9Vdc)

±10%

1.55 V/El..

Manual charge voltage

480.15 Vdc (528.2-479.3)

±10%

1.65 V/El.

Emergency charge voltage

N.A.

±10%

N.A.

Static control tolerance

±1%

Output voltage Ripple

<1% VRMS

Max. Rectifier output current

310A

Battery current limitation on automatic charging mode

60 A

10÷20% C10

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Previous in Forum: Motor Terminal Overvoltage in Steady State by Using VFD in ETAP Analysis   Next in Forum: Lambda Value of LED?

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