A surge protector is an equipment that protects the machines against surges that comes from the source or inside the facility. Inside this device, there is a zinc oxide varistor, which allows the electric current to pass through it if only the voltage is greater than the rated. (mais…)
I believe everybody wants to save energy, so I will share some measures that I made years ago with my old CRT monitor 17 inches for different conditions:
(for such measurements, I used a clamp ammeter and I considered power factor equal to 0.80) (mais…)
Electric shock is established when our body behaves as a part of the circuit, offering a way for the current pass. This way is the one which offers less resistance.
It can have many causes, such as: contact with wires or sources energized, insulation failure, nature disturbances, accidental energizing, maneuver mistakes, electric arc (arc usually comes with severe burns, due to large amount of heat released). (mais…)
A differential residual device (known as DR in Brazil) acts through according the difference between two variables (in our case, currents). There is a toroid inside the enclosure which has a coil for each input. Among these, there is also a auxiliary coil connected to a cut relay. (mais…)
A lot of things is spoken about economy in our bills provided by fluorescent lamps. They dissipate 80% less then tungsten ones (incandescents); so, tendency is to think that they’re friend of nature or more environmentally friendly.
But, is it really true? Let’s review some points: (mais…)
Switching a electrical machine off is often misguided. Its best idea can be: a set of procedures that provides total elimination of electrical hazards in the shutdown of a machine (or a system).
The simple turning off action in the circuit breaker does not guarantee a safe condition for work. (mais…)
A grounding is the intentional connection of a electric to the Earth. It can be: protective, functional or temporary.
Protection: provides electric protection for human beings by offering a scape way to the current.
Functional: the Earth is used as a return conductor. (mais…)