Answer / ajay

megger is used to measure insulation resistance.multimeter is used to measure coil resistance

Answer / raghavendran

The working mechanism of a Meggar and a Multimeter with
regard to measuring a resistance is the same.In this case
Voltage is applied across the body whose resistance is to be
measured.
1)for meggar, there will be two coils namely 'control coil'
and 'deflection coil'.The 'Control Coil' will always be kept
energized by the DC Source.If the insulation strength is low
then there will be current flow through the 'deflection
coil' and the resulting torque in the coil will produce
deviation in the pointer connected to a permanent magnet.The
torque produced by the two coils will be opposite in nature.
2)for multimeter,the control coil will be replaced by a
spring whose tension tends to keep the pointer in one
direction.when current flows through the deflecting coil (ie
when weak insulation)a torque, opposite to the tension of
the spring is produced tending to move the pointer in other
direction.thus showing the corresponding Ohmic Value.

Answer / pillay

meggar is actually a brand name, but it is more often than
not associated with with insulation resistance testers.The
meggar tester /or insulation tester actually uses a high
voltage at its terminals to do the measurements thus being
more efficient in driving In a current and than the
measurements are made.
Multimeter as the name says is used for a variety of
measurements but using basically the same moving coil.when a
high resistance or very small leakage is to be tested using
a multimeter it usually fails because of its in ability to
drive a current through a very high resistance circuit and
give a correct reading.
I would always use a MEGGAR tester for insulation testing
and a multimeter for other testing.

in thermal power plants by opening the turbine governor valve increase the generator load. how

3 Answers  

---

how can we charged the battery in DG

2 Answers   MTS,

---

How to calculate cable size for a particular load? i have 12 MW,11KV Motor 3 Phase, what should be cablesize? What are the points to remember for cable sizing calculations?

2 Answers  

---

can u describe the method used for protection of transmission line.

0 Answers   IBM,

---

how to calculate the distance relay faulty zone?pls explain?

0 Answers  

---

HI FRIENDS,MYSELF & MY GROUP OF FINAL YEAR ELECT ENGG. ARE MAKING A 50/3HZ,5HP,1000RPM,440V SALIENT POLE SYNCHRONOUS GENERATOR.COULD ANYONE OF U TELL ME WHAT COULD BE THE ADV. & DISADVANTAGES OF MAKING SUCH A LOW FREQN.GENERATOR/

2 Answers  

---

what is subtransient , transient and study state ac components

2 Answers  

---

Explain cmrr?

0 Answers  

---

How do you select the pickup value of the relay?

0 Answers  

---

How you calculate the repturing capacity of a HRC fuse

0 Answers   CPCL, RSCL,

---

Is it necessary to seperate the DG earth grid with Electricity Board earth grid for protecting the DG set. if yes why?

2 Answers   BARC,

---

How we can calculate what type of supply we need for an example sometimes we take 11 KV and sometime 33KV from EB ?

4 Answers  

---