Ohmmeter - Flexible Manufacturing System

Seminar TopicOhmmeter Sensor

Flexible Manufacturing System

Karan Prajapati 11BME083

Yudhishthir Ramnani 11BME084(7th Semester, Mechanical Engineering, School of Technology)

1

Introduction An ohmmeter is an electrical instrument that

measures electrical resistance.

Ohmmeter has an electronic circuit that passes a constant

current (I) through the resistance, and another circuit that

measures the voltage (V) across the resistance.

Types

Micro-ohmmeter

Megohmmeter

Micro-ohmmeters make low resistance measurements.

Megohmmeters measure large values of resistance.

2

Main Specification3

Current leakage - the rate at which current flows

through a ground conductor and is borne away safely.

Resistance range - measures a material’s opposition to

the flow of electric current.

Test time - the time required to complete the test.

Megohmmeter Also known as megger.

The prefix "meg" describes anumerical value of 1,000,000.

An electrical test instrument designedto test extremely high resistances byproducing a DC (direct current)voltage of between 300 and 15,000volts, supplied at low current values.

Breakdown strength of ElectricalInsulation.

4

Application5

To test the insulation resistance of wires, cables,

transformers, and electrical motors. Others are used to

verify that devices such as aircraft fuel pumps meets

manufacturer IR specifications.

Megohmmeters are also used to test the insulation-

resistance of cable reels, rectifiers, solid-state diodes

and other electrical components.

6

Micro-ohmmeter Measure low value of resistance.

Require low value of voltage to beapplied.

Except, all the working principles asof Megohmmeters.

Having higher accuracy thanMegohmmeters.

7

Application8

Aerospace metallic coating resistance measurement Winding resistance measurement of motors and transformers Bonding verification on earth/ground systems Weld joint integrity verification Contact resistance measurement of breakers and switch-gear Aircraft and rail bonding checks Wire to terminal connections and resistance checks Battery strap resistance checks Cable joint and bus bar connection checks Mechanical bond tests

9

Reference10

http://en.wikipedia.org/wiki/Ohmmeter

http://www.edgefx.in/ohmmeter-circuit-and-types-of-ohmmeters/

http://www.ehow.com/how_5202652_use-megohmmeter.html

ftp://pti.kpi.ua/pub/electric/Microchip/disc1/download/appnote/devspec/16c5x/00512e.pdf

http://www.prolexdesign.com/images/evohmmeter.jpg

http://www.wisegeek.com/what-is-a-megohmmeter.htm