Impress your friends by using correct units and abbreviations

[Warpspeed]

You dudes have all been advising Boris Johnson, I just know it.

True,
But we we were really surprised when he actually believed us.

 

[Rednecktek]

11/64 of a cubit. Expect it to produce about 20 cords over a lustre.

20 cords! There always seems to be a burn ban, how am I ever going to get through that in my fire pit?

 

[burgerking]

More about wires:

THHN stands for Thermoplastic High Heat-resistant Nylon-coated.
THWN stands for Thermoplastic Heat and Water-resistant Nylon-coated.
XHHW stands for XLPE (which itself is an abbreviation for cross(X)-linked polyethylene) High Heat-resistant Water-resistant

You might come up with nomenclatures like: 20/7, 10/7, 8/7
First Number is the AWG gauge of the wire and the second number is the number of conductors.
Below, 8AWG is 8/7
1AWG would be 1/19.
This makes sense if you are in a hardware store, looking at a box labeled "3/7" and wondered what size is that spool...

 

[Justins311]

Yeah, as an engineer the mis-use of abbreviations and multipliers does grate somewhat (I even find it in supposedly "professional" equipment documentation!), although usually it's interpretable.

India opening a 100mW solar farm - Yeah, I get that, I have one on my calculator.
A 10KW heater - OK although I'm not sure what Kelvin-Watts are useful for.

Then along come the power-bank makers and specify capacity in mAh 'coz it gives a nice big number. Someone then asks "how big should a 33,000MAh power bank be?" - The size of a large building perhaps.

As a mechanical engineer I try not to be too critical, the rule of the land seems to be "The engine was doing X RPM's" when what you really just wrong is "revolutionS per minuteS". I'm sure I'm guilty of Lifepo4 and KW typos, as long as its interpreted in the correct setting you just let it go. Everyone is strong in their own field.

 

[Supervstech]

Someone then asks "how big should a 33,000MAh power bank be?" - The size of a large building perhaps.

especially when the voltage of the bank isn’t specified…

Imagine a 33,000MAh 400V bank… good LORD that would be huge…
My calculator doesn’t go that high…

 

[Supervstech]

Sorry, I didn't know there were "ALT" characters past 256? Where can you find this?

The alt character set repeats… I think.

 

[wattmatters]

Imagine a 33,000MAh 400V bank… good LORD that would be huge…

13,200 GWh

That's the storage capacity of 38 Snowy Hydro 2 pumped hydro power storage stations.

 

[12VoltInstalls]

and the second number is the number of conductors. STRANDS

 

[crossy]

I always thought it was number of strands first then strand size, at least it is for metric e.g. 7/02 is 7 strands of 0.2mm diameter (small ish equipment wire) .

 

[Warpspeed]

In Australia, both in the old imperal and new fangled metric, its number of strands/wire size

 

[rin67630]

More about wires:

More about wires:
european-cables-and-wires-abbreviations

 

[RichardL]

Takes me back to the first lesson of Physics O-Level (UK education)
That whole first lesson and homework was listng/learning Si units!

It's locked in my memory as not the most exciting introduction to an amazingly diverse subject.

Doesn't mean I get them right of course - 15 years old was a long time ago

 

[Mannfamilywoodworks]

CME: Coronal Mass Ejection

ICME: Interplanetary Coronal Mass Ejection

CME is a Sun Fart. ICME is a Sun Fart that reaches Earth. More appropriate definitions will influence edits of this post. ?


Some folks are forecasting more of these over the next few years.
Maybe we should consider preparing for these in our solar systems, maybe not. That is a discussion for another thread.

I believe you can purchase emp shields and whole home surge protectors. I may be wrong may be correct

 

[Warpspeed]

If the Sun does decide to throw up again, as it did in 1859, it could send us all back to the age of sail and horses and buggies.

In 1859 there was very little electrical equipment, and of course zero electronics.
It was called the "Carrington event".
https://duckduckgo.com/?t=ffab&q=carrington+event&ia=web

 

[Spunky]

A - amps, a unit of current. Named after André-Marie Ampère.
V - volts, a unit of voltage. Named after Alessandro Volta.
W - watts, a unit of power. Named after James Watt.
Ω - ohms, a unit of resistance. Named after Georg Ohm.
h - hours
k - kilo (SI prefix for 1000)
K - Kelvin, a unit of temperature. Named after William Thomson, 1st Baron Kelvin. Not really relevant in solar discussions.
m - milli (SI prefix for 1/1000)
M - mega (SI prefix for 1000000)

Current is measured in amps - A
A battery's voltage is measured in volts - V
A battery's current capacity is measured in amp hours - Ah

Shouldn't "V - volts, a unit of voltage.", be a unit of Electromotive force? And "A battery's voltage is measured...", be, A battery's EMF is measured in volts - V?

My apprenticeship wasn't that long ago, but much smarter people seems to dwell here.

Also, kVAR hasn't been covered yet. Almost got there when comparing watts and voltamps.

It's what we refer to capacitors as, when trying to change the PF (power factor not pico farads) on the primary distribution lines (substation to homes). I'd guess that is because they are designed and built for a frequency of 60hz and their effect is known?

Hopefully this impresses friends and doesn't make enemies :-D

 

[rmaddy]

Shouldn't "V - volts, a unit of voltage.", be a unit of Electromotive force?

I tweaked it to say "electric potential.

For the Wikipedia entry on "Volt":

The volt is the derived unit for electric potential, electric potential difference (voltage), and electromotive force

"A battery's voltage is measured...", be, A battery's EMF is measured in volts - V?

A battery has a voltage (electric potential difference).

 

[rin67630]

I tweaked it to say "electric potential.

For the Wikipedia entry on "Volt":

The volt is the derived unit for electric potential, electric potential difference (voltage), and electromotive force


A battery has a voltage (electric potential difference).

Without intensity, a plain voltage will only generate a very low force (excepted at kilovolts on your hair)

 

[Larry Oswald]

So what is C ?

Capacitance or the speed of light ?

For sure and sometimes. Is mass m or M? The gravitational constant is always G.

 

[32 volt boater]

AC vs A/C - AC is alternating current. A/C is air conditioning

Thanks.

 

[Benmanji]

So what is C ?

Capacitance or the speed of light ?

c (lowercase) is a symbol for the speed of light (under specific conditions). C (uppercase) is the symbol for a coulomb, a unit of electric charge.

 

[Warpspeed]

We need a bigger alphabet.

 

[wattmatters]

We need a bigger alphabet.

That's why we use the Greek alphabet so much.

 

[midahar]

The following are common units and their abbreviations. Note that unit abbreviations are case-sensitive. While some units can be understood when written incorrectly, some have a completely different meaning if the wrong case is used. Avoid any possible confusion or ambiguity and use the correct case.

A - amps, a unit of electric current. Named after André-Marie Ampère.
V - volts, a unit of electric potential. Named after Alessandro Volta.
W - watts, a unit of power. Named after James Watt.
Ω - ohms, a unit of electrical resistance. Named after Georg Ohm.
h - hours
k - kilo (SI prefix for 1000)
K - Kelvin, a unit of temperature. Named after William Thomson, 1st Baron Kelvin. Not really relevant in solar discussions.
m - milli (SI prefix for 1/1000)
M - mega (SI prefix for 1000000)

Current is measured in amps - A
A battery's voltage is measured in volts - V
A battery's current capacity is measured in amp hours - Ah
A battery's energy capacity is measured in watt hours - Wh. Wh is simply Ah x V. Many times it is shortened to kilowatt hours - kWh. Example: 5120Wh or 5.1kWh.
An inverter is measured in watts - W. Many times a value is shortened. 4000W can be written as 4kW. Really large systems could be in megawatts (MW) or even gigawatts (GW). Small electronics might be measured in milliwatts (mW).
A wire's resistance is measured in ohms - Ω. Many times the resistance is very small such as 0.002Ω commonly written as 2mΩ (two milliohms).

--------------------------

AC vs A/C - AC is alternating current. A/C is air conditioning

--------------------------

While not a unit, one common abbreviation that should be written correctly is for Lithium Iron Phosphate batteries. The correct written form is LiFePO₄ though most people find LiFePO4 is much simpler to type. LFP is a shorthand abbreviation understood in the context of this forum when discussing batteries.

Incorrect abbreviations would include LiFePO (lithium iron phosphorus oxide), LiFePo (lithium iron polonium), LiFePo4 (lithium iron tetra-polonium), LiFeP04 (using a zero instead of a capital O), LiFe (lithium iron), LifePo4 (wrong case on the F and O).

Note that there is a lithium-ion polymer battery typically written as LiPo. That is not at all the same as LiFePO₄. You do not want to confuse the two types. Though both of those types are specific examples of the more general lithium-ion (Li-ion) batteries.

I use Google speak to to take your diction you don't know what you're going to get it sometimes goes to Mars and gets the strangest things but that was interesting about l i f e p04 I hadn't noticed that it was a zero instead of an o

 

[Supervstech]

I use Google speak to to take your diction you don't know what you're going to get it sometimes goes to Mars and gets the strangest things but that was interesting about l i f e p04 I hadn't noticed that it was a zero instead of an o

Incorrect. It is PO for the molecule of Phosphate PO4
ONLY THE 4 IN THE NAME IS A NUMBER. Li is for Lithium, Fe is for Iron, PO4 is for the molecule phosphate.

Phosphate - Wikipedia

en.m.wikipedia.org

 

[Housingsoft]

The following are common units and their abbreviations. Note that unit abbreviations are case-sensitive. While some units can be understood when written incorrectly, some have a completely different meaning if the wrong case is used. Avoid any possible confusion or ambiguity and use the correct case.

A - amps, a unit of electric current. Named after André-Marie Ampère.
V - volts, a unit of electric potential. Named after Alessandro Volta.
W - watts, a unit of power. Named after James Watt.
Ω - ohms, a unit of electrical resistance. Named after Georg Ohm.
h - hours
k - kilo (SI prefix for 1000)
K - Kelvin, a unit of temperature. Named after William Thomson, 1st Baron Kelvin. Not really relevant in solar discussions.
m - milli (SI prefix for 1/1000)
M - mega (SI prefix for 1000000)

Current is measured in amps - A
A battery's voltage is measured in volts - V
A battery's current capacity is measured in amp hours - Ah
A battery's energy capacity is measured in watt hours - Wh. Wh is simply Ah x V. Many times it is shortened to kilowatt hours - kWh. Example: 5120Wh or 5.1kWh.
An inverter is measured in watts - W. Many times a value is shortened. 4000W can be written as 4kW. Really large systems could be in megawatts (MW) or even gigawatts (GW). Small electronics might be measured in milliwatts (mW).
A wire's resistance is measured in ohms - Ω. Many times the resistance is very small such as 0.002Ω commonly written as 2mΩ (two milliohms).

--------------------------

AC vs A/C - AC is alternating current. A/C is air conditioning

--------------------------

While not a unit, one common abbreviation that should be written correctly is for Lithium Iron Phosphate batteries. The correct written form is LiFePO₄ though most people find LiFePO4 is much simpler to type. LFP is a shorthand abbreviation understood in the context of this forum when discussing batteries.

Incorrect abbreviations would include LiFePO (lithium iron phosphorus oxide), LiFePo (lithium iron polonium), LiFePo4 (lithium iron tetra-polonium), LiFeP04 (using a zero instead of a capital O), LiFe (lithium iron), LifePo4 (wrong case on the F and O).

Note that there is a lithium-ion polymer battery typically written as LiPo. That is not at all the same as LiFePO₄. You do not want to confuse the two types. Though both of those types are specific examples of the more general lithium-ion (Li-ion) batteries.

Thanks, Maddy.