Cables
Measurement of insulation resistance (IR)
The measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables. As a production test, this test is often used as a customer acceptance test, with minimum insulation resistance per unit length… Read more
Apr 28, 2012 | By Jignesh Parmar
Electrical Lectures
Short review of resistance, reactance and impedance
Resistance is essentially friction against the motion of electrons. It is present in all conductors to some extent (except superconductors!), most notably in resistors. When alternating current goes through a resistance, a voltage drop is produced that is in-phase with… Read more
Apr 08, 2012 | By Edvard Csanyi
Energy and Power
Inspection of electrical installations in home (2)
Every installation deteriorates with use and age. Therefore, one must ensure that the safety of users is not put at risk and that the installation remains in a safe and serviceable condition. Continued from part I – Inspection of electrical… Read more
Mar 26, 2012 | By Edvard Csanyi
Energy and Power
Megger Insulation Resistance Test
As you know good insulation has high resistance and poor insulation relatively low resistance. The actual resistance values can be higher or lower, depending upon such factors as the temperature or moisture content of the insulation (resistance decreases in temperature… Read more
Mar 13, 2012 | By Edvard Csanyi
Electrical Lectures
Types of neutral earthing in power distribution (part 2)
Resistance grounding has been used in three-phase industrial applications for many years and it resolves many of the problems associated with solidly grounded and ungrounded systems. Resistance Grounding Systems limits the phase-to-ground fault currents. Continued from Types of neutral earthing… Read more
Feb 09, 2012 | By Jignesh Parmar
Electrical Lectures
Types of neutral earthing in power distribution (part 1)
In the early power systems were mainly Neutral ungrounded due to the fact that the first ground fault did not require the tripping of the system. An unscheduled shutdown on the first ground fault was particularly undesirable for continuous process… Read more
Feb 06, 2012 | By Jignesh Parmar
Energy and Power
Ohm’s Law – The Resistance
It is intuitive that voltage and current would be somehow related. For example, if the potential difference between two ends of a wire is increased, we would expect a greater current to flow, just like the flow rate of gas… Read more
Sep 02, 2011 | By Edvard Csanyi
Energy and Power
Resistive heating explained in details
Whenever an electric current flows through a material that has some resistance (i.e., anything but a superconductor), it creates heat. This resistive heating is the result of “friction,” as created by microscopic phenomena such as retarding forces and collisions involving… Read more
Jul 27, 2011 | By Edvard Csanyi
Metering
How To Use A Digital Multimeter
A digital multimeter is used to make various electrical measurements, such as AC and DC voltage, AC and DC current, and resistance. It is called a multimeter because it combines the functions of a voltmeter, ammeter, and ohmmeter. Multimeters may… Read more
Feb 23, 2011 | By Edvard Csanyi
Electric Motor
Keeping Motor Windings Dry
Special provision should be made to protect motor windings which operate in a damp atmosphere or are subject to condensation of moisture when out of service for long periods. Motors located in galleries of dams are frequently subject to continual… Read more
Dec 14, 2010 | By Edvard Csanyi
Metering
Megger Tests
The insulation resistance meter test method for determining the condition of electrical insulation has been widely used for many years as a general nondestructive test method. A serious limitation of this test is that its operating voltage of 500 to… Read more
Nov 26, 2010 | By Edvard Csanyi
Energy and Power
Harmonic Distortion
Harmonic distortion is caused by nonlinear devices in the power system. A nonlinear device is one in which the current is not proportional to the applied voltage. Figure 1 illustrates this concept by the case of a sinusoidal voltage applied… Read more
Nov 23, 2010 | By Edvard Csanyi
