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Rooney
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Join Date: Jun 2009
Posts: 49

Automatic Star - Delta - Star Converter

06/30/2011 1:17 AM

Dear All,

i have heard of a device named Automatic Star - Delta - Star Converter for the variable load applications - where the load is jerk load (less than 40% on the lower side and high).

I want to know -

1. The concept / working of the device

2. The response time between Star to delta conversion and vice-versa

3. Successfull practical applications, which you might have observed

4. Limitations, if any

5. Approximate Cost

Your valuable suggestions are awaited.

Thanks and regards,

Rooney
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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#1

Re: Automatic Star - Delta - Star Converter

06/30/2011 3:49 AM

<...response time between Star to delta conversion and vice-versa...>

If it is wired correctly, the conversion will be instant.

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TonyS
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#2

Re: Automatic Star - Delta - Star Converter

06/30/2011 5:36 AM

Is this a follow on from your thread http://cr4.globalspec.com/thread/44171 ?

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TonyS
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#3

Re: Automatic Star - Delta - Star Converter

06/30/2011 6:13 AM

Have a look at http://www.vijayenergy.com/dscm.html which I've no doubt you have done all ready otherwise I don't think you would be asking the question.

Change over can't be instantaneous, as the contactors would short-circuit the mains.

All I can see this unit doing is wearing out the contactors.

OK it will save energy but at what cost to the equipment?

Another box with energy saving written on it hits the dust as far as I'm concerned.

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JRaef
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United States - Member - New Member Engineering Fields - Power Engineering - New Member

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#4

Re: Automatic Star - Delta - Star Converter

06/30/2011 10:01 AM
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TonyS
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#5
In reply to #4

Re: Automatic Star - Delta - Star Converter

06/30/2011 1:26 PM
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Tornado
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#6

Re: Automatic Star - Delta - Star Converter

07/01/2011 1:54 AM

This may not save as much energy as you hope. When a delta-connected motor runs under light load, the current drops. Comparing star current to full-load delta current is not valid.

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