Answer / baikunth

As we know DC current is uni-directional.The deflection
system attached to the megger is generally PMMC type which
eorks only with DC. Another reason is when DC current flows
in the winding of a motor or transformer the capacitance and
inductance do not act upon the current and the only leakage
current that flows through the insulation is measured.This
gives faster and accurate measurement.If we use an AC megger
the reading will be erroneous because the capacitance of
winging will allow to flow high current and breakdown of
insulation will not occur due to alternating action of
current.

Answer / abaya

We can create voltage like 5kv,1kv,using DC but we can not produce that type of voltage using Ac because it require more space as compare to Megger.

Answer / k.prakashchandra

Further you maintain potential difference for a substantial
period,which is possible with DC

Why motor initial starting current is high?

9 Answers   Pennar,

---

Do u know any one? how to find out in motor rated amps? formula?

0 Answers   Banking, ET,

---

what is impedence of transformer? its formula

1 Answers  

---

depletion layer will form beforre biase or after bias ?

2 Answers  

---

Why negative feedback is preferred in the control system?

0 Answers  

---

---

what is the main difference between power devices and signal devices

0 Answers   Wipro,

---

In an panel board if the outgoings are power plugs and motor equipments...what should we choose as the incomer of the of the panel board?? MCCB OR ISOLATOR?? Should we use ELCB protection??if so where??

2 Answers  

---

what is meant by vector group in transformers? wy we r using that?

1 Answers  

---

Why tripping not occur when the transmission breaks? Doesn't we provide earthfault protection for it?

1 Answers  

---

give me applications of sequence bridges . (used in 3 phase un balanced systems)

0 Answers  

---

What is the difference between Welding Transformer and Normal Transformer?.

2 Answers   DAE,

---

when a hand crancked meggar is used to check most three phase induction motors, how many tests r rquired? Why?

1 Answers  

---