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Automatic change over

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gfactor

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Pls I need a circuit that will automatically switch over to generator and back to electricity mains when there is supply with alarm. Also considering when there's low voltage from mains
 

santoshaxl

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you have to tell me your generator is 3 phase or single phase generator
 

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nandhu015

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Simple solution is power a relay with mains and connect the mains in normally open and generator in normally closed positions.

There are relays available which will operate in 230V
 

pranam77

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This can be achieved just by using relays. But to use it you must be able to think how. Its nothing but switching by the relay contacts. Cheers and good luck
 

amjadali56

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here is a simple circuit for ur requirement.
single Phase, adjustable low voltage cut out, LED and Buzz for main voltage.
need more advancement requirement or any help?
 

pranam77

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here is a simple circuit for ur requirement. single Phase, adjustable low voltage cut out, LED and Buzz for main voltage. need more advancement requirement or any help?
Why complication while the same function can be achieved just by relays? In case of low voltage you'll have to start the generator first and not Shifting the load to the generator. Why one will sit in the dark unless the generator is activated at the same time. This circuit shown below is commercially used for changeover.
Cheers
 

amjadali56

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excellent point Pranam! a man with a thinking mind..........
 

ibitechs2005

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This is the right place to be,in term of good and acurate infomation about functional circuits.Thank you.............
 

joshnosh

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2 problems you still have to start the generator or leave it running
and the sudden change and lack off power until its running from the generator will make most devices reset
 

chuckey

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I was going to mention that. sequence is :- 1. mains fails(goes low) 2. generator starts 3. generator volts stable for 5 seconds. 4. change over to generator. 5. mains returns and is stable for 10 seconds. 6 change over to mains. 7. generator runs for 10 minutes for cooling system and alternator cooling to cool things down then generator switches off.
Frank
 

Andy G

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whats the KVA rating of the generator?
is it a portable gasoline(petrol) generator?
 

pranam77

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I was going to mention that. sequence is :- 1. mains fails(goes low) 2. generator starts 3. generator volts stable for 5 seconds. 4. change over to generator. 5. mains returns and is stable for 10 seconds. 6 change over to mains. 7. generator runs for 10 minutes for cooling system and alternator cooling to cool things down then generator switches off. Frank
Thank you Frank for the flow chart. In simple the circuit given by me is typical Indian design. (Keep it cheap and simple). In addition to that it also has a 12 volt 500 Ma transformor driving a 12 volt SPDT relay which is energised when the power resumes to switch off the engine. No timers are used. But your idea is excellent and advanced with which one can design a complete changeover system.
Cheers
 

ibitechs2005

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But one may need a snapy so that some of the load does not reset,do you think this timming won't cause this?
 

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