All manufacturers mention value of DC resistances for their cables. We normally use ac resistance for calculation purpose. What is nescessitiy of mentiong DC resistance then? Is it only for confirmation to limitation of resistances to standard?
Please help me out. In advance, thanks....
I would like to know regarding standard cable size. Who defines it, i mean which standar has defined this. Is somebody is aware why the standard concluded for a particular size. For exampl, why cable size is of 70 sq.mm. only and not 75 sq.mm.
In advanse thanks..........
I have observed one thing regarding insulators of LV busduct in one project. For low voltage busduct connecting transformer and switchboard, I have observed that the voltage rating of insulators is 3.3kV. Why these insulators are up-rated?
Can anybody help me? In advance, Thanks.
I have one question regarding motor power factor. I need to calculate the voltage drop in cable at starting of motor. How to calculate motor starting power factor of motor? Does any motor manufacturer mention it? IS there any relationship with running power factor.
Please help me out. In...
I do have one question in my mind.
while going through the specifications for cables i do not find short circuit withstand capacity mentioned in case of LV cables. But these are clearly specified in HV or MV cables.
My question is why there is no much importance to withstand capacity in case...
I have observed that normally, low voltage DG sets ratings mentione din kVA and high voltgae DG sets in MW. Can somebody put his input regarding DG sets ratings. Is there any standard for mentioning these ratings? Whether it shall be mentioned in MW ort in MVA? I do agree that all electrical...
Can anybody guide me regarding rating of VFD? how it is co-related to motor kW rating? Is it nescessary to de-rate VFD i.e. if motor kW is 90 kW, then VFD rating should be 110 kW. is it so?
Also, what other factors to be considered for determination of VFD rating as well as motor kW rating...
Can somebody explain the earthing of VFD fed motors? Is normal motor body earthing is sufficient? Is earth falut curren flow back to main power supply when winding of motor gets earthed? I am asking this question as there is VFD in between main power source and motor i.e. there is conversion of...
i would like to know the information about current trasformer. I have dual core current transformer with three terminals viz s1, s2 and s3. s1 is common and earthed. Between s1 and s2 i get ratio of 200/1 and between s2 and s3 i get ratio of 400/1. if i would like to use s1 and s2 with ratio of...
