Newbie says HELLO all !!!

[Maverick1]

Maverick here...

:signthankspin:

The thanks is in anticipation for all the assistance I will be asking for:  :Blushing

I am currently studying for EAL 4337/8 Initial Verification / Periodic Inspection & Testing. 

I am struggling a little with a couple of the questions mainly the calculation ones. I feel Im doing ok, but if its ok with you guys / girls I'd like to call upon your vast experience.

Anyway hoping to contribute in the future..

Cheers all.. Guinness

 

[roys]

Welcome, we are always willing to help with homework questions providing you make a stab at them first.

 

[Maverick1]

Thankyou Roy 

 

[Maverick1]

Cheers Roy,

One question Im struggling with is 3 circuits have insulation resistance values of 100M ohms / 50 / 40 respectively..

I have 1 over 100 = 0.01 / 1 over 50 = 0.02 / 1 over 40 = 0.025 totally 0.055  (when tested together the overall value will  be?)

Im struggling converting this to M Ohms..

 

[Maverick1]

Getting to late off for a brain rest... think the answer is 18.33 but eh does anyone know if this is correct??

Ta.

 

[Sharpend]

Hi maverick, welcome to the nuthouse, the only ice here is in the drinks! 

Why hey do you think it needs converting? 

 

[roys]

One question Im struggling with is 3 circuits have insulation resistance values of 100M ohms / 50 / 40 respectively..

I have 1 over 100 = 0.01 / 1 over 50 = 0.02 / 1 over 40 = 0.025 totally 0.055  (when tested together the overall value will  be?)

Im struggling converting this to M Ohms..

Do you know what the M stands for?

 

[roys]

Do you know what the M stands for?

The reason for asking is that they are all in M Ohms and the answer is in M Ohms so the 6 zeroes in all the sums will just carry through to the final answer which will be in M Ohms, so you are as well just working with the 3 IR readings you have.

You have done your calc so far correct as in you have worked out the bottom line = 0.055. Now all you have to do is divide1 by 0.055 and you have your answer in M Ohms.

What do you get?

And the question I always ask myself is, does it look realistic given the numbers.  That helps make sure you haven't done something silly (doesn't always work).

 

[Maverick1]

Hi Sharpend / Roy, - the Sharpend the question asked "When tested together the overall value will be?"

and the given answers were 18M 5M 50M etc, so my workings out to this point = 0.055 wouldn't be the correct answer.

Hi Roy, yes I know what Meg stands for: It seems you have identified the last steps being I needed to divide 1/0.055 = 18M so cheers all for your help.

I must have missed that step somewhere couldn't find it in the 7671 or GN3 which I had been suggested to look in or its there and I simply can't find it...  :Salute

 

[roys]

Hi Sharpend / Roy, - the Sharpend the question asked "When tested together the overall value will be?"

and the given answers were 18M 5M 50M etc, so my workings out to this point = 0.055 wouldn't be the correct answer.

Hi Roy, yes I know what Meg stands for: It seems you have identified the last steps being I needed to divide 1/0.055 = 18M so cheers all for your help.

I must have missed that step somewhere couldn't find it in the 7671 or GN3 which I had been suggested to look in or its there and I simply can't find it...  :Salute

Yip 18.18M Ohm is what I got, well done.

 

[Maverick1]

cheers Roy, you put me onto it... Ta.