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cpshajeer1988
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Join Date: Oct 2012
Posts: 5

Motor mccb Design

10/16/2012 7:24 AM

how to design the mccb for motor. is it 2.5 times the full load current
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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
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#1

Re: Motor mccb Design

10/16/2012 8:43 AM

The correct way is to follow national electrical design and installation standards. In the UK, British Standard 7671 gives full protocol on co-ordination between circuit protective devices, cables and motor overloads.

The circuit protective device looks after the cables. The motor overload device looks after the motor. Co-ordination ensures both are correctly selected. So it would be wrong, in principle, to use the mccb to try to protect against overload as it cannot do this, and motor failures will ensue.

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pnaban
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Join Date: Jun 2010
Location: srilanka
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#2

Re: Motor mccb Design

10/16/2012 11:40 PM

Try motor circuit breaker.You should select not design.

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obouill
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France - Member - New Member

Join Date: Feb 2012
Location: Grenoble, France
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#3

Re: Motor mccb Design

10/17/2012 2:48 AM

All info on :

http://www.electrical-installation.org/enwiki/Basic_motor_protection_scheme:_circuit-breaker_%2B_contactor_%2B_thermal_relay
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electricalexpert65
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Join Date: Oct 2009
Posts: 2061
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#4

Re: Motor mccb Design

10/18/2012 9:32 AM

Pl. inform me your mail ID thro this forum's mailbox so that I can send you a technical paper on the subject. It is too large to be posted here directly.
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electricalexpert65 (1); obouill (1); pnaban (1); PWSlack (1)

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