motor cals help needed

[searley]

i have got this and need to no which equation is right if any ?

a transformer has 1000v (v pri) ans 200v (v sec).if the current (pri) is 5a,calc the secondary current ?

which way is right 1000/200 = 5 then 5x5 =25

or

1000x5/200 = 25

thanks for looking

 

[Andy™]

i have got this and need to no which equation is right if any ?a transformer has 1000v (v pri) ans 200v (v sec).if the current (pri) is 5a,calc the secondary current ?

which way is right 1000/200 = 5 then 5x5 =25

or

1000x5/200 = 25

thanks for looking

both methods work. go with the one you remember

 

[msb2003]

You have the choice here, either use the voltage ratio, 1000:200 or 5:1 and if voltage goes down, current goes up by the same ratio (P=IV)

Or remember on an ideal transformer, power in = power out

so primary side 1000v x 5a = 5000w primary power,

secondary power 5000w / 200v gives 25A

 

[a1]

 

[a1]

That was from here: http://www.electricianforum.co.uk/electricalformulas.html

 

[searley]

cheers admin got the formulas you have put on here but looking for level 3 formulas.

 

[a1]

That is the formula used in level three too Mate.

 

[a1]

When It comes to doing your 301. Make sure you know your motors, and your incuctance, capacitance and resitantace formulas. I sat mine last Wednesday and I had some crackers in there.

There was a beauty of a question on Lumer too.



As soon as I get some time, I will put on a load of the level 3 formulas too.

 

[searley]

can you remember any questions from your 301 and did you pass ?

cheers for the help with the formulas you put on the site they came in Handy

 

[a1]

can you remember any questions from your 301 and did you pass ?cheers for the help with the formulas you put on the site they came in Handy

Distinction.

 

[a1]

A lot of the questions are what you have been revising, just worded differently.

 

[mikey-c]

Well done admin. Just 4 more to go?

 

[a1]

Thanks Mikey. Three and a half to go.

I have to do the paperwork side for the 302 as I have done the testing.