Where -48 volt DC use & why?????????

Categories >> Engineering >> Electrical Engineering
Suggest New Category

Question Posted / shri..

10 Answers
31538 Views
Ericsson, INDUS, Indus Towers, Telecom, I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

Where -48 volt DC use & why?????????..

Answer / pundlik wanwe

48v Dc is used in the telecommunication circuit.

Is This Answer Correct ?

57 Yes

6 No

Where -48 volt DC use & why?????????..

Answer / rabi

A negative line voltage helps to reduce the corrosion from
electrochemical reactions occurring on a wet telephone line.
Also -48v DC is more stable than +48 volit, so -48 V is
preferred.

Is This Answer Correct ?

41 Yes

5 No

Where -48 volt DC use & why?????????..

Answer / subra

in -48v dc system positive + is earthed. Negative- is
giving to the equipment.Normally in automobile dc system
negative is earthed.positive is giving to equipment.in
positive grounding system we can avoid corrossion on
terminals.

Is This Answer Correct ?

15 Yes

3 No

Where -48 volt DC use & why?????????..

Answer / anant gupta

it's true that telecommunications equipments operates on the
negative 48 volts DC.

how can we get any voltage while we are grounding the
positive terminal. pls give details.....

Is This Answer Correct ?

9 Yes

4 No

Where -48 volt DC use & why?????????..

Answer / shri..

Thanks for repply

But why not using + ve 48 volt????

Is This Answer Correct ?

10 Yes

8 No

Where -48 volt DC use & why?????????..

Answer / muralichppl

what is difference between + 48V and - 48V and how can we we
get individually

Is This Answer Correct ?

8 Yes

7 No

Where -48 volt DC use & why?????????..

Answer / avinash

Even if a high supply current comes,the equipment can
compensate due to -ve voltage

Is This Answer Correct ?

6 Yes

5 No

Where -48 volt DC use & why?????????..

Answer / maxiquiet

why do we prefer -48 volt instead of -24volt or -12 volt
etc. ??

Is This Answer Correct ?

5 Yes

4 No

Where -48 volt DC use & why?????????..

Answer / jitender kotwal

first understand what -48 volt means,it means that when we
grounded the nagtive termnal of supply making it to zero
potential means nagative supply, in communacations we use
negative voltage to reduce the noise and hum level.

Is This Answer Correct ?

4 Yes

5 No

Where -48 volt DC use & why?????????..

Answer / hemant

WHEN CLOUDS STRIKE THEY PRODUCE -VE CHARGE ,& FOR DISCHARGE THEY NEED THE ZERO POTENTIAL AT EARTH.IN TELECOM WE R GROUNDING THE -VE TERMINAL OF SUPPLY TO MAKE IT ZERO POTENTIAL .IF WE GROUND THE +VE TERMINAL THEN ALL THE EQUIPMENT WILL DAMAGE OR FIRED BECAUSE CLOUD WILL CHOOSE LOW RESISTANCE
+VE CHARGED ANTENAS.THAT IS THE REASON WE USE -48V.

Is This Answer Correct ?

6 Yes

14 No

Post New Answer

More Electrical Engineering Interview Questions

why transformer rating in kva ?

14 Answers Eltel, RRB,

What are the main factors to be considered(In terms of energy conservation) while selecting a new air compressor?

1 Answers

why need to be maintain power factor for industrial customer?

2 Answers

what is package substation.how many types they have

0 Answers ABC,

What are capacitive,resistive,inductive surge absorbation? What is ferranti surge absorber? What is lagrangian cost? What is Px operator?

0 Answers

why is the rating of transformer done in kva and not in kw.

21 Answers Honeywell, Satyam,

how to testing the AC 3 phase motor? and what is the test procedure & kits required for testing?

3 Answers

can i know how to design overcurrent setting and earth fault for 11kv & o.433kv system assuming tx 1000kva.

2 Answers

what is mean by harmonics?Type of harmonics?

6 Answers

corona happens more in ac or dc?

5 Answers MAHINDRA,

short circuit test of transformer gives what?

9 Answers NTPC,

Hi, i want to know is meant by power quality? How it can calculated ? How we can improve?

1 Answers

For more Electrical Engineering Interview Questions Click Here