Answer / kirti

we use 2 core, one '+' & one '-' as we all know. there is
no meaning of providing earthing in d.c as protection can't
be given by earthing in d.c.

Answer / akshat sharma

beta,, in DC ther no use of earth coz we cant provide protection the reason is becauseearth fault vl not make current to flow to ground...!!!! its only in a.c that current flows to ground.
in d.c we need to complete the ciruit with "+" and "-" terminals only. for much detailed reasons resd working of an d.c cell

Answer / sagarika

what abt d other part question? can we use 33 core ?

Answer / surajit mishra

You can use a 3-core cable if it you are driving a DC motor from a thyristor converter or a DC Drive. The Drive chassis, motor body must be connected to a common earth. In other words, you use one core for +ve, one core for -ve and the one end of the 3rd core to connect the Drive chassis, the other end to motor body. Thyristor converters generate harmonics of higher frequencies. If the cable length is long it can pick up capacitive voltage and will cause electrical interference. Using the 3rd core to connect the Drive chassis to motor body eliminates this. Of course if the DC motor is of small capacity, you can simply keep the 3rd core as a spare core.

Answer / avinash

sir,we also use 3 wire,1 wire for +,2 wire for -,and wire
for earthing

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