Motor-Generator Set

Dear Mr. Dickson,

Further to the good suggestion by Mr. Msmad, i would like to add a further points :

In order to select the cable sizes, following factors need to be considered :

1) Voltage rating and 3 phase/1 phase

2) frequency of supply

3) Voltage drop

4) load current

5) Thermal current( which will decide the heating of cable and subsequent thermal equilibrium the conductors will reach)

6) Protective device( if the current rating of protective device is much higher than the actual load current in the cable, derating factor needs to be considered. it is recommended that the rating of protective device is as close as possible to the actual load current flowing in the cable)

7) ambient temperature

8) short circuit current of the source and the fault clearing time of the protective device. Higher the fault clearing time , higher cross-section of conductor is required.

9) Most important : whether copper conductor or aluminium conductor.

10) Method of cable laying and grouping

11) Length of cable

The above points mentioned is incomplete, but the above points which are mentioned, i am of the opinion is that are most important and major. In some cases, even harmonic current needs to be considered for cable sizing( for case to case basis)

For much better information and tools for calculation of cable sizing please check this site : http://myelectrical.com/pages/cables/cableSizing.aspx.

Thanks and Regards

→ British Standard 7671.

i m working on Dc motor ,means i m giving suppy to dc motor in motor generator set ,so how to load dc motor in motor generator set.