Hi I'm new, wondering if anyone could help....

[ben1991]

Hi i'm ben, from newcastle, and i have a massive interview tomorrow, I was given a sheet of questions i could be asked but there is a few i am still unsure about, i know this is pretty sudden but i really need help, if you can thanks...

National Grid Questions.

1st question is : "the voltage of the electrical circuit in the room" - this is asking me what the average voltage of a circuit in a room in a house is, i believe - that is the main question that i need answering.

2nd question is : what are methods of sizing a fuse?

Electrical in the Home Questions.

1st quesion is : How is a 12V battery transformed to a 20,000V at the spark plug? I think this is via a coil unit transformer, but im not sure, thanks for all the help guys if you can help me!


Again guys sorry to be asking a question in my first post, but i need this, thanks if you can help.

 

[Phil]

allegedly 230v give or take a few either way.

 

[Phil]

when you say sizing a fuse do you mean selecting a fuse

 

[Dan]

Welcome to the forum!

 

[lecstar]

Hi i'm ben, from newcastle, and i have a massive interview tomorrow, I was given a sheet of questions i could be asked but there is a few i am still unsure about, i know this is pretty sudden but i really need help, if you can thanks...

National Grid Questions.

1st question is : "the voltage of the electrical circuit in the room" - this is asking me what the average voltage of a circuit in a room in a house is, i believe - that is the main question that i need answering.

2nd question is : what are methods of sizing a fuse?

Electrical in the Home Questions.

1st quesion is : How is a 12V battery transformed to a 20,000V at the spark plug? I think this is via a coil unit transformer, but im not sure, thanks for all the help guys if you can help me!


Again guys sorry to be asking a question in my first post, but i need this, thanks if you can help.

ans 1 In uk 230v -6% to +10% but usually around 240V

ans 2 not sure what you are asking but basic ohms law V/R will give you current for circuit and therefore fuse size needs to carry that current.
For proper fuse selection other factors need to be taken into account, such as prospective fault current, current carrying capacity of cable, load characteristics, disconnection times to name but a few.

ans 3 not an auto elec but suspect coil has something to do with it and the gap at the end of the spark plug.

All the best with your interview

 

[eskimo39]

From the web:

Inside an ignition coil, there are hundreds of rows of tiny copper wire, all coiled up and wrapped in a circle. Once the 12 volts travels through this series of wire, the output is many times greater than the input--10,000 to 20,000 volts. Performance applications (racing ignitions, for example) might reach 40,000 or even 50,000 volts. The increase in voltage is the reason the ignition coil gets hot after a very short time.

Read more: How Does an Ignition Coil Work? | eHow.com How Does an Ignition Coil Work? | eHow.com
​

 

[ben1991]

thanks a lot all, hope it can help me, cheers!

 

[Des 56]

If you pass a current through a coil , a magnetic field will be set up

and the other statement is

If a magnetic field passes through a wire, it is the reverse of the above


Passing a steady 12 volt through a coil will produce a magnetic field,when that 12 volt supply is interupted,the magnetic field collapses.the collapse of that field will provide the 20Kv for the spark

Contact points in the distributor used to provide that inturruption,when the inturruption occurs is what used to time the spark for the ignition of fuel

 

[ben1991]

cheers lads (lasses if there is any) the interview went ok, i didnt know everything they asked but they said they didn't expect me to know everything, as im only applying for an apprenticeship, not a qualified post. Fingers crossed!

 

[davidcookie]

cheers lads (lasses if there is any) the interview went ok, i didnt know everything they asked but they said they didn't expect me to know everything, as im only applying for an apprenticeship, not a qualified post. Fingers crossed!

and congratulations, Ben!

 

[ben1991]

David.. You must be psychic, i got the position 1 hour ago! crazy stuff!

but yes, congratulations ben!!

 

[lecstar]

Congratulations and good luck in your new career.
Now the hard work starts eh!

 

[juliapho]

Congratulations from me also and good luck in all you do. And always remember about the voltage in the electrical circuit in the room – it might be useful to you in the future – and you heard it here first .

 

[ben1991]

thanks alot again guys, i'll keep in touch with the forum, Looks like im going to be needing it@!!

 

[Phil]

well done nice to hear a good result.