Alejandro Nava

Electrical engineer
631 followers · 51 following

Hello! I'm Alejandro Nava and I like science, specially physics and a few topics in math. In 2021 I got a
degree in electrical engineering. I ask/answer that kind of stuff but I also like to read life… Read more

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Electrical Engineer at Full Data Comunicaciones 2024–present

Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta Graduated 2021

Lives in Venezuela
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Knows Spanish

Joined September 2014

ES Active in Spanish 42 answers

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Power Systems Engineering

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 Alejandro Nava
Read books and took classes about power systems & circuits · Updated Dec 31

What is the power formula for the 3-phase system?

Short answer (summary): 1. Powers for single-phase AC systems operating in sinusoidal steady-state In
general: 2. Powers for three-phase balanced AC systems operating in sinusoidal steady-state 2.1. In
general: 2.2. In a wye-connected load: 2.3. In a delta-connected load: Long answer: Keep reading.Read
Most…
more

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · 14h

How should a power inverter be configured?

A (power) inverter has the purpose of transforming the energy stored in a battery bank, in the form of
DC voltage, into AC voltage to feed AC loads like appliances, lighting, motors, IT and networking
equipment, etc. Here’s how they should be configured: 1. DC input (battery side): These parameters…
Read more

Alejandro Nava
Electrical engineer · Mon

What is the ideal pixel density for a monitor or TV, and how do you calculate it?
Pixel density can be expressed in various ways, but the most common one is linear pixel density in
pixels per inch of diagonal. It indicates how many pixels there are in the diagonal line of the screen. In
other words, how tightly packed together the pixels are in the screen. Given resolution and siz… Read more
What's the difference between screens/displays (DLED, QLED, OLED) and panels (VA, IPS)? Why
are screen types specified in TVs and smartphones, while panel types in gaming monitors?
No answer yet · Last followed Sun

Alejandro Nava
Read books and took classes about power systems & circuits · Updated 14h

Can I connect the output Mcb breaker of the inverter to the output of the main circuit breaker of
the home directly in parallel (in order to connect to the loads)? The inverter support bypass
mode?
I think I know what you mean.

I've worked with hybrid (all-in-one) PV inverters and inverter-chargers, from brands like Victron, Growatt,
MPP Solar, Powest.

They have an AC input connection to the grid, an AC output connection to the loads, a DC input
connection to the battery bank (battery energy storage system), and a PV input connection to the solar
array.

When the unit (hybrid inverter or inverter-chargers) has AC input (i.e. it's working in grid mode), internally
the AC output wires are connected to the AC input wires: output phase to input phase, output neutral to
input neutral. Hence, output = input in regards to voltage. So this is called “pass-thru" or “bypass” mode
too for these types of inverters. For example, if your local grid has say 118.3V at 59.98 Hz, then your AC
loads will see that same voltage.

This is unlike when the inverter has no AC input, in which it is in inverter/battery mode, and you should
see a better voltage like 120.0V at 60.0 Hz, for example.

Below I show a block diagram of this. (Ignore the “DC load", I drew this for a general power converter.)
Figure 1. Block diagram of a power converter with pass-thru/bypass at AC output and with DC regulator at
DC output, during grid mode + solar power and battery bank discharged. Image source: own.

Few hybrid inverters work with double conversion (like online UPSes), in which the AC input is first
rectified and then inverted to the AC loads even during grid mode. See the following block diagram. This
is technically better for sensitive loads or critical applications like data centers and hospitals.
Figure 2. Block diagram of a power converter with double conversion at AC output and with DC regulator at
DC output, during grid mode + solar power and battery bank discharged. Image source: own.

In regards to your question, you should not do what you suggest, as others have said.

Is the GIGABYTE Z790 AORUS Elite AX motherboard compatible with Intel Core i7-12700K
CPU? Some say yes, but the CPU chipset is Z690.
1 answer · Last followed Feb 20

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Updated Feb 19

How can electrical harmonics affect the UPS operation and do they response of inverter
unsynchronize alarm?
UPSes, specially cheap ones that are line-interactive instead of online (double conversion), may not
recognize an AC input that is a modified sinusoidal waveform (such as from certain inverters) or that
has a high total harmonic distortion (such as from portable generators), or that has a too high o…Read more

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Jan 18

How do I convert three phase (without neutral) to single phase?

Simply use any two phase wires of the three-phase system. If the nominal line-to-line voltage of the
system doesn't match the rated voltage of the single-phase loads, you'll need a transformer. If you need
one phase wire to be grounded, then from the previous transformer you can ground either wire;…Read more

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Jan 16

Can old stranded electrical cable be used to make ground rods, similar to how bare solid wire is
used for grounding rods?
Yes, you can use stranded uninsulated wire as a grounding electrode, but not by driving it through the
soil like a ground instead, but instead by burying it. Make a loop or a grid.p That's called a ground ring or
ground mesh.… Read more

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Jan 13

Can a wire with broken insulation cause a short circuit?

Well this proves Quora bot is still learning very basic logic.

Personal notes 3 · Follow

Posted by Alejandro Nava · Jan 10

Grounding and bonding for a multi-store mall [Unfinished answer draft]

Figure 1. Image source: own. Figure 2. Image source: own.… Read more
 Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Updated Jan 31

What are the criteria for choosing an electrical circuit breaker?

For basic residential circuit breakers, at least the following: * Number of poles: Whether the circuit is
single-phase two-wire line-to-neutral, single-phase two-wire line-to-line or single-phase three-wire, or,
three-phase. * Mounting: DIN rail (European) or, for other countries, bolt-on, plug-in, or fee… Read more

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Jan 6

Can you explain the differences between a TT, TNS, and TNCS earthing system?
Yes, I can, Quora bot. I already did it here, including the other arrangements:

Alejandro Nava's answer to What are the types of grounding (earthing) arrangements? What are IT, TT,
TN-C, TN-S and TN-C-S grounding arrangements?

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Jan 5

Can you explain the difference between TT and TN earthing?

Yes, I can, Quora bot. I already did it here, including the other arrangements: Alejandro Nava's answer to
What are the types of grounding (earthing) arrangements? What are IT, TT, TN-C, TN-S and TN-C-S
grounding arrangements?

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Jan 4

What happens to power if the current in an alternating current (AC) circuit is zero?
Depends on what you actually mean. When the instantaneous current is zero, the Instantaneous power
is also zero. However, the active/real power won't be zero, because the average of the instantaneous
power is not zero, even though the average current is zero. When the RMS (or peak) current is zero,
Read
th…more
 Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Dec 31

What factors affect power factor in AC circuits?

For single-phase AC circuits (sinusoidal or not): * Power factor is the ratio of active power to apparent
power. So it depends on how much active power the device consumes or delivers relative to its
apparent power: \text{pf} = \dfrac{P}{S} \tag 1 For example, if a load consumes 1000VA and 800W, Read
then…
more

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Updated Jan 4

Why do high voltage cables move and bend during a short circuit, even breaking insulation and
support?
Any conductor (wire) that carries current, AC or DC, creates a magnetic field, and hence a magnetic
force. The stronger the current, the stronger the force. Since current flows in closed circuits, at least two
wires are required. And usually the two wires are close together. So they exert forces on e… Read more

Personal notes 3 · Follow

Posted by Alejandro Nava · Updated Dec 31

Summary on harmonics in power systems [Unfinished answer draft]

* Balanced periodic non-sinusoidal instantaneous line voltages with half-wave symmetry can never
contain triplen harmonics (neither in a three-wire nor a four-wire three-phase network), they can contain
only the non-triplen odd harmonics. This is also true for phase voltages in a delta-connected devic…
Read more

Alejandro Nava
Bachelor’s degree in Electrical Engineering, Universidad Rafael Urdaneta (Graduated 2021) · Updated Sun

What is the neutral current magnitude of a four-wire three-phase network operating in

sinusoidal steady-state conditions with the line currents being balanced in phase shift but
unbalanced in magnitude?
Short answer: The magnitude of the neutral current in a three-phase four-wire network operating in
sinusoidal steady-state conditions, with the line currents having balanced phase shifts (120° between
one another) but unbalanced magnitudes, is the square root of the sum of the squares of the lineRead
cu… more

Personal notes 3 · Follow

Posted by Alejandro Nava · Dec 23

What is the instantaneous active and reactive power of a single-phase non-sinusoidal AC circuit
in terms of active and reactive power, when the voltage and current have the same fundamental
frequency? [Unfinished answer draft]
In a two-terminal network/circuit/device/component/load operating in non-sinusoidal steady-state
conditions, the instantaneous voltage v(t) across the network and the instantaneous conventional
current i(t) through the network are given by: v(t) = V_0 + \sqrt{2} \displaystyle\sum_{n = 1}^{\infty}
ReadV_{…
more
 Personal notes 3 · Follow
Posted by Alejandro Nava · Dec 23

What are the instantaneous active and reactive currents of a single-phase non-sinusoidal AC
circuit, when the voltage and current have the same fundamental frequency? [Unfinished
answer draft]
Let’s assume that the instantaneous voltage v(t) across a two-terminal network and the instantaneous
current i(t) through the network are both periodic in time with same fundamental period (or frequency):
v(t) = V_0 + \sqrt{2} \displaystyle\sum_{n = 1}^{\infty} V_{n, \text{rms}} \cos{(n \omega_0 t +… Read more

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