B
basejumper31
Hi folks,
I'm working my way through the start of a Trevor Linsley book for the 2365 lvl 2 ahead of starting the course in September, and I have some basic questions which I wondered if someone might be able to give me feedback on.
I can't post in the training section yet as I haven't started the course yet.
p.65 of the book,
the following example is given:
"The insulation resistance measured between phase conductors on a 400v supply was found to be 2MΩ. Calculate the leakage current."
(and then it gives the working and the answer, as follows)
"I = V/R
Therefore: I = 400V / 2 x 10[SUP]6 [/SUP]Ω = 200 x 10[SUP]-6 [/SUP]A = 200 µA"
My questions –
I'm working my way through the start of a Trevor Linsley book for the 2365 lvl 2 ahead of starting the course in September, and I have some basic questions which I wondered if someone might be able to give me feedback on.
I can't post in the training section yet as I haven't started the course yet.
p.65 of the book,
the following example is given:
"The insulation resistance measured between phase conductors on a 400v supply was found to be 2MΩ. Calculate the leakage current."
(and then it gives the working and the answer, as follows)
"I = V/R
Therefore: I = 400V / 2 x 10[SUP]6 [/SUP]Ω = 200 x 10[SUP]-6 [/SUP]A = 200 µA"
My questions –
- why does the author use 2 x 10[SUP]6 [/SUP]Ω instead of just saying 2000000Ω ?
- Why does it follow that 400/2 x 10[SUP]6[/SUP] equates to 200 x 10[SUP]-6[/SUP]? This may just be because I am no longer familiar with algebraic maths, and have got used to doing everything in decimals, but even so, why choose 200 x 10[SUP]-6[/SUP]? Why not say 2 x 10[SUP]-4[/SUP] instead?
- Why do they state the answer in microAmps? If I understand SI notation correctly, 200 microAmps is the same as 2 milliamps, so would it not make more sense to give the answer in terms of milliamps? Or is it because it is a convention to give answers in terms of whole numbers? or is it because milliamps don't exist / are generally not used, in the same way that kilometers are used, but you never hear people talking about megameters, they'd say a thousand kilometers instead?
- Should I not worry too much about these kind of details, and just accept it for what it is, and assume I'll pick up these kind of conventions as I go along, or is it good practice to want to pull things apart if I don't understand them?
Thanks in advance :/