Tests and electrical insulation

CONTINUITY CHECKS: This it is the simplest measurement that we can realise with multetro. It is called? Continuity? in the circuits and electric appliances to a measurement of very low resistance, generally of the order of zero ohms that conduction or direct union between two elements indicates. The continuity is generally used for the verification of the good state or conduction of a fuse, a lamp, a conductor, etc.

TESTS OF ELECTRICAL ISOLATION IN CONDUCTORS:
Each one of the electrical conductors of an installation are that he is fed a motor, generator, transformer, etc. this cover carefully with some form of electrical isolation. The wire in if, generally of copper or aluminum, he is a good conductor of the electrical current that gives power to its equipment. The isolation must exactly be the opposed thing of a conductor. It must resist the current and maintain it in his trajectory throughout the conductor.
The isolation tests are based on the Law of Ohm. The intention of the isolation that surrounds a conductor is similar to the one of a tube that takes water, and the Law of Ohm in electricity can be understood more easily by comparison. The pressure of the water. In the following figure is this comparison. The pressure of the water of a pump causes the flow throughout the tube. If the tube had flight, water would be spent and certain pressure would be lost.
In the electricity, the voltage is similar to the pressure of the pump and causes that the electricity flows throughout the copper wires. Like in a water tube, certain resistance to the flow exists, but he is much smaller throughout the wire than through isolation.
The common sense says to us to greater voltage will have current major, Also, that to smaller resistance of the wire will have more current with the same voltage. Really, this is the Law of Ohm, that is expressed this way in the form of equation, like:

V = I * R
Where: V= Voltage in volts.
Current I= in amperes.
R= Resistance in Ohm.
Nevertheless, no isolation is perfect (its resistance is not infinite), so that certain amount of electricity flows throughout the isolation or through a earth. So current millionth of Ampere only can be of (an microampere) but is the base of the test equipment of the isolation. This small amount of current month, by all means would not damage a good serious isolation but a problem if the isolation has been deteriorated.
So that the Isolation Is deteriorated: When the electrical or conductive system of their plant is new, the electrical isolation must be in the best form. In addition, the manufacturers of the conductor have improved continuously their isolation for the services of the industry. In spite of everything, even nowadays, this subject to many effects is isolation that can cause that it fails: damages you mechanize, vibrations, heat or excessive cold, corrosive dirt, oil, steam, humidity of the processes, or simply the humidity of a cloudy day.

In different degrees, these enemies of the combined isolation are working as spends the time with the electrical effort that exists. In agreement punctures are developed or cracks, the humidity and the cruds penetrate in the surface of the isolation and provide a trajectory of low resistance for the flight of current. Once they begin, the different enemies tend to help themselves to each other and allow an excessive current through isolation.
As Resistance of Isolation is moderate: A good isolation has high resistance; a poor isolation has low resistance relatively. The real values of resistance can be higher or lower, following factors as the temperature or the moisture content (the resistance diminishes with the temperature or the humidity). Nevertheless, with the registries and little of common sense, you can have a good Image of the conditions of the isolation of values that are only relative.
The probador of isolation? MEGGER? it is an instrument that gives a direct readout of the resistance of isolation in Ohm or megaohms.

CONDUCTORS: Thread of material that owns the capacity to allow the passage of the electrical current, is constructed generally of Copper or Aluminum, many are covered with insulating materials and the rest where it allows it to the process does not own isolation.