Struggling please help

[daws124]

A 230v single phase double wound transformer has an output of 20A at 110v

Determine the

kVA rating....
Primary current...
Transformation ratio...

Please explain my brain is mush! Thank you.

 

[bigbaddave]

On here we like you to have a go of your homework first.. Have a bash and we will advice

 

[Richard Burns]

Think about what you have coming into the transformer and what you have going out.
Consider the relationship between current and voltage across a transformer.

 

[daws124]

Yeah I understand that completely but I have not come across these words in the reading so far,so it's just thrown me a bit! Is the primary current 41.8A?? Just need a bit of guidance :/

 

[daws124]

Is the Transformation ratio...2.09:1???

 

[Fox]

I saw you're from Harrogate - not at Harrogate College by any chance are you - if so how are you finding it? In my experience I'd advise you to enrol with York College!

One of the guys that qualified the year before I did was teaching 2330 the year after he qualified, it was an absolute disgrace.

We had students teaching the tutors how to terminate MIC and SWA. The college had failed numerous external C&G audits due to the internal mess the department was in, and the inability/lack of skill and experience of the tutors.

I pray that the whole department has had a massive overhaul before the college releases more 'electricians' into the trade!

 

[daws124]

Seriously lost with this please help

 

[derek]

Is the Transformation ratio...2.09:1???

Looks good to me. Perhaps it might help to look at P=VI and compare the primary and secondary sides.

 

[Fox]

http://www.electriciansforums.net/e...68164-electrical-theory-level-2-problems.html

 

[Silly Sausage]

OK......

V[SUB]P[/SUB]/V[SUB]S[/SUB] = N[SUB]P[/SUB]/N[SUB]S[/SUB] = I[SUB]S[/SUB]/I[SUB]P[/SUB]

Power = V[SUB]P[/SUB]I[SUB]P[/SUB] = V[SUB]S[/SUB]I[SUB]S[/SUB]

 

[cmac70]

That's the best pointer with out giving the answer. Should be a bit easier now.

 

[daws124]

I only started the course on Monday so I apologise for my ignorance. I think I have the primary current at 41.8A and the transformation ratio at 2.09:1 it's just the kVA rating I'm lost with,having said that are the other answers correct?? :/
Thanks for the guidance.

 

[daws124]

Sorry people but do Measure the kVA rating on the input or output??

 

[Silly Sausage]

For simplicity's sake, assume it is a 100% efficient transformer, so the Power In = Power Out. (which is its kVA rating)

Use the equations up above to work out the Primary current, I[SUB]P[/SUB] and the kVA rating.

Your turns ratio is correct!

 

[daws124]

Ok so I've got 9.614kVA,41.8A and 2.09:1 as my 3 answers. Hopefully that's correct?? Appreciate this help a lot. Thanks