How does an Earth Ground Resistance Tester work and why do we need it?
The Earth Ground Resistance Meter is a resistance meter that measures the resistance of the earth.
All of the system’s components are grounded using the earth electrode. Unrestricted earthing protects electrical equipment and personnel against fault currents. The earth’s long-term viability is in doubt.
The fault current then travels to the earth as a result. It protects the system from injury.
Before touching down equipment or surfaces, it is necessary to limit the resistivity of the ground in the concentrated areas where soil cavities have been dug. Low impedance is maintained in a specific region by measuring ground impedance. This enables the fault current to flow freely to the ground. The micro OHM meter is used to assess the Earth’s resistance.
A manual generator is used to make earth resistance testers. A rectifier and a three-phase inverter are the earth tester’s two major components. A rectifier is a device that transforms alternating current (AC) to direct current (DC). Only DC or direct current can be utilized with the Earth Tester. The commutator and commutator ascend the shaft of the DC generator. Using a commutator and a commutator, the tester installed two commutators at the same time. Each commutator is made up of four fixed brushes.
It is connected to the generator armature in a series configuration.
Brushes are used to transmit electricity from stationary parts to moving parts of equipment. The brush and commutator are always connected to ensure constant current flow.
How the earth resistance tester works:
The pressure coil and current coil each have two connections. Permanent magnets are used to connect these pairs. The auxiliary electrode is shorted and coupled to a synchronized pair of current and pressure coils. One end of the other pressure coil is connected to the rectifier and the other end is connected to the ground electrode. The current coil is connected in the same way.
The DC generator is inextricably linked to the potential coil. The permanent magnet is surrounded by the potential coil. The pointer is calibrated to the scale and is attached to this coil.
Poor earthing/grounding causes not just unneeded downtime, but is also unsafe and raises the chance of equipment failure. We might be at risk of electric shock if we don’t have a good grounding system, not to mention instrumentation mistakes, harmonic distortion concerns, power factor issues, and a slew of other potential problems.
A deliberate connection from a circuit wire, generally the neutral, to a ground electrode implanted in the earth, is known as earth grounding. Equipment grounding guarantees that the body of functioning equipment is grounded.
Except for a link between the two grounding systems, these two grounding systems must be maintained separately. This eliminates voltage potential discrepancies from causing a probable flashover due to lightning strikes.
What exactly is the Fall-of-Potential test?
First, disconnect the desired ground electrode from the connection to the site. Next, the ground electrode is connected to the tester. Next, in the 3-pole potential drop test, two ground spikes are inserted into the ground in a straight line away from the ground electrode. A distance of 20 meters (65 feet) is usually sufficient. Then press the start button on the megameter.
What is the value of Earth’s resistance?
Before you start measuring the earth resistance, you need to determine the appropriate maximum earth value.
Countries, neutral systems, and installation types have different soil resistance standards. Power distributors such as EDF require a small amount of resistance to ground and are often less than a few ohms. Therefore, it is important to confirm the appropriate requirements for a test installation in advance.