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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