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Participant

Join Date: Mar 2011
Posts: 3

Panel Board

03/16/2011 3:36 AM

We use panel board inbetween Transformer and Motor/Pump. In that panel board we use MCCB, Ammeter, Voltmeter, fuse, Capacitor for transformer and Contactors at incomming side. And we will use same in outgoing side. Now my question is based on which logic we will calculate rating of MCCB, Ammeter, Voltmeter, fuse, Capacitor for transformer and Contactors. Please give me detail explation and formulae. If possible explain for 630KVA, 33/0.433KV LT Transformer and 200HP(2+1) Pump Set.

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Guru
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#1

Re: Panel board

03/16/2011 5:47 AM

It's impossible to second guess someone else's design. Contact the manufacturer.

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Guru

Join Date: Jun 2010
Location: srilanka
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#2

Re: Panel board

03/16/2011 5:48 AM

Give more information like primary/secondary rated current of transformer,rated current of motor,starting method.SC level in HV switchboard etc

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pnaban
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#3
In reply to #2

Re: Panel board

03/16/2011 6:16 AM

For transformer

primary current= 11.02A

Secondary Current = 840A

For motor

Rated Current = 260A.

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Guru

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#4
In reply to #3

Re: Panel board

03/16/2011 11:55 AM

For the motor you did not give the starter type which determines the starting current for which the LV breaker which feeds the motor should not trip. Do you want all 03 motors or only 02 motors to run together?. The incoming main LV breaker should carry the total current drawn by motors(2 or 3) and extra for auxiliary loads. It should not trip for motor starting current. Specify fault level at bus bars for main CB. LV voltmeter need not exceed 500V.LV ammeter for incoming CB should indicate load currents(2 or 3 motors). Regarding capacitor CB check with PFC contractor. Include an EFR and voltage monitor relay.For each motor depending on starting method CB should be selected,which should not trip for the starting current. If necessary add an ammeter.For selection of motor contactor refer manufacturer's catalogue. If you buy motor+starter you need not worry about contactor or OC relay. A single line diagram should be drawn first.

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Join Date: Dec 2011
Location: chennai
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#5

Re: Panel Board

12/12/2011 11:38 PM

Dear Ananth,

The MCCB rating ( drawout type) for transformer is 1000 amps and it is based on transformer rating only and not based on the end load being a source. However, the rating of the transformer is based on the total connected load with diversity factor taken into account.

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anand purushothaman (1); ananth (1); pnaban (2); TonyS (1)

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