Answer / cnu

in the measurement of voltage in any circuit we measure the
voltage of one conductor with respect to another.

In DC supply we have two conductors namely Positive(+) and
negative(-). if we consider 48V DC across the two
conductors, then if we measure the value on the positive
conductor with respect teo the negative conductor the value
is +48V. if we measure the same value on the negative
conductor with respect to the positive conductor then the
value will be -48V. this 48V is the instantaneous value of
the DC supply.

Where as in AC we have two conductors namely Phase and the
Neutral. always the Phase constitute the current path and
the neutral forms the return path. we say that the AC
voltage is sinusoidal. that is it varies from positive to
negative when seen with respect to the neutral.

its impossible to measure the instantaneous value of the AC
supply bcoz it keeps on continuosly varying. so for the AC
supply we consider the RMS value (Root Mean Square Value)
as the voltage of the supply. so in this case there is
always the same value when measured with respect to any
conductor. so the AC voltage does not have polarity.

Answer / naren

when we are measureing dc voltage in negative circuit we
have -48V DC , but in AC there is no negative supplay and
hance we get 48V AC from Phase to Nutral as well as Nutral
to Phase.

In constant power region of 3-phase IM torque-speed characteristics, if frequency increases flux A does not alter B decreases C increases D none of above

0 Answers  

---

what is the function of switch gear ?

10 Answers   Exxaro,

---

How to minimize the eddy current losses?

0 Answers  

---

hw to find transformer is in normal position? whether its in charged condition or not? except humming sound?

9 Answers   ABB,

---

can you check the current and voltage of a 12 V battery by a digital multimeter in this fashion that apply the digital multimeter across the battery terminals directly ? say yes or no ... i sais yes ........... is this true or false ? plzz tell me and also explain ........ plzz thanks

4 Answers  

---

---

What is the difference between generator and turbo-generator

5 Answers   iGate,

---

why should be the frequency is 50 hz only why not others like 45, 95 56 or anything , why should we maintain the frequency constant if so why it is only 50

3 Answers  

---

In India,we use 230V,50HZ,where as many other countries use 110V,60HZ what r d advantages and disadvantages of each of them?

8 Answers   GVK,

---

Difference between ups

32 Answers   Emerson, Tata Power,

---

how to calculate the no. of earth pits required for an electrical installation?

1 Answers   Mepax,

---

An active element is one which a. Supplies energy b. Absorbs energy c. Supplies energy and convert energy from one form to another

0 Answers  

---

What is the diffrece between ACB & MCCB

8 Answers  

---