Recent content by Neil Hayes

Thanks cnh1995 :) Do you mind if I ask why we have 4 parallel paths? Is this standard for a 4 pole lap wound armature? Having the answer is good but understanding why is the best thing and my lesson notes are fairly unclear, to say the least!

Homework Statement A 4 pole lap wound armature has 16 coils, each with a resistance of 0.1 ohms. Calculate the resistance of the armature? Homework EquationsThe Attempt at a Solution Hi there fellow members, I'm currently doing a section of my course which deals with Electrical machines. The...

It sure did. Thanks again :smile:

Hi there Magoo, I just got my results back from the assignment. I submitted my effort on post no 8 and got it correct. I got a distinction on the assignment so I'm well chuffed. Only another 100 to go lol ( well it fell like 100 anyway! ) Thanks for taking the time to work with me on the site...

Will do and thanks again for your time to date :)

Hi there Magoo, It seems that my last post seems to be the correct way of going about the problem. I won't know for sure as I've to submit my work tomorrow but I'll let you know. Thanks again for your help to date! Neil

Please see attached photo for the impedance diagram which shows the system prior to the addition of the neutral earthing resistor. The figures that I've written out are relate to fault conditions that are set out in the question. On the right hand side I have 3419 V which is the potential...

Hi again Magoo, Apologies for not including a drawing. I will hand draw out one tomorrow and post it on the thread here. I need to look at my notes to see if your drawing is similar to what I have. The 0.424 ohms from above was the impedance of the cables from the transformer to the motor...

Hi there Magoo, Thanks a million for the reply to my post :) There is an example in my lesson notes and if I was to follow the process it would go as follows ( using the values given in the question ). Impedance of cables feeding the motor and the Earth return path to the transformer is : Z...

Homework Statement . [/B] An 11kv motor is fed by cables from a transformer via switchgrear, having a phase impedence of 0.3 + j0.3 ohm. The Earth return path to the transformer neutral has a resistance of 0.42 ohm. Determine a suitable value of neutral resistance if the voltage rise at...

[SIZE=16px][FONT=Helvetica Neue]Hello again everyone! I'm actually just looking at the question there again and think that I made a mistake. I thought that the .42 ohms was the impedance but I think that the impedance from the transformer to the motor is Z = 0.3 + j0.3 which is .42 but I think...

Homework Statement An 11 kV motor is fed by cables from a transformer via switchgear, having a phase impedance of 0.3 + j0.3 ohm. The Earth return path to the transformer neutral has a resistance of 0.42 ohm. Determine a suitable value of neutral resistance if the voltage rise at the motor in...

Hi again Simon, Thanks for the reply ( again )! All makes sense. Thanks for your help clearing up my confusion :smile: Neil

Hi Simon, Thanks for your reply! In my lessons the volt drop per ampere per meter value is always given. In this question I have been given no current or voltage but I have worked out the resistance of the 95 mm² cable per meter at 70 degrees. Seen as voltage is current times resistance I was...

Homework Statement [/B] Determine the resistance of a conductor and the volt drop per ampere metre at 70°C for a 95 mm2 pvc/swa/pvc copper cable. The temperature coefficient of resistance is 0.004 per °C. Homework Equations [/B] R70 ( resistance at 70 degrees ) = R20 [ 1+( temperature...