110v 220v definitions WHY?

[edguy3]

Originally Posted by a64pilot

I believe it’s due or voltage drop. Nothing will increase voltage, but of course voltage will drop over distance, higher resistance older wire etc.
So if you start out at the max, you can get away with longer runs on wiring after the transformer etc. so you save money by having fewer transformers.
If your at the middle of the range, then you will have to do something to stay within allowable tolerances with less drop that if you started at the top.

Higher voltage means lower current - Lower current means less power loss in the wires.

"The primary reason that power is transmitted at high voltages is to increase efficiency. As electricity is transmitted over long distances, there are inherent energy losses along the way. High voltage transmission minimizes the amount of power lost as electricity flows from one location to the next. How? The higher the voltage, the lower the current. The lower the current, the lower the resistance losses in the conductors. And when resistance losses are low, energy losses are low also. Electrical engineers consider factors such as the power being transmitted and the distance required for transmission when determining the optimal transmission voltage.

Transmitting Electricity at High Voltages

[s/v Jedi]

Originally Posted by a64pilot

I believe it’s due or voltage drop. Nothing will increase voltage, but of course voltage will drop over distance, higher resistance older wire etc.
So if you start out at the max, you can get away with longer runs on wiring after the transformer etc. so you save money by having fewer transformers.
If your at the middle of the range, then you will have to do something to stay within allowable tolerances with less drop that if you started at the top.

That’s the same thing. When the voltage is made higher, the current drops lower for equal power transfer. With the lower current through the same resistance cable, voltage drop is less.

[cyan]

Originally Posted by edguy3

Higher voltage means lower current - Lower current means less power loss in the wires.

"The primary reason that power is transmitted at high voltages is to increase efficiency. As electricity is transmitted over long distances, there are inherent energy losses along the way. High voltage transmission minimizes the amount of power lost as electricity flows from one location to the next. How? The higher the voltage, the lower the current. The lower the current, the lower the resistance losses in the conductors. And when resistance losses are low, energy losses are low also. Electrical engineers consider factors such as the power being transmitted and the distance required for transmission when determining the optimal transmission voltage.

Transmitting Electricity at High Voltages

FYI, you need to be careful with the context. To say on it's own "higher voltage means lower current" is not specific enough.

For instance:
If you are transmitting a fixed amout of power over a given transmission line, then using higher voltage would require lower current to achieve this.
In this context, higher voltage means lower current (is needed).

If you are simply observing conductors with a fixed impedance and load, then when you apply a higher voltage you will observe a higher current.
In this context, higher voltage means higher current (is supplied).

Also, efficiency is not the only consideration. Cost of copper wire can be a factor.
In the local sense, if you do have a fixed load like a 1500 Watt coffee maker, then higher voltage has more advantages than simple efficiency. My European friends (at 230V) can get by with home/boat wiring that is safe for about 6.5 amps. (1500W/230A) My American friends and I (at about 115V) need to use more expensive (thicker conductor) wiring that is safe for 13 amps. (1500W/115A)
These differences just get worse when you move from coffee making to air conditioning.

[evm1024]

Just a footnote - I spent some time doing realtime programming in various fields. One such was for a rather large Power Agency with a lot of dams in the PNW.

Frequency (e.g. 60 Hz) has a tolerance but the Agency I contracted counted every cycle and adjusted the frequency such that the average was exactly 60 Hz. I presume that they still do this as well as other power utilities.

Why? It is all about the clocks (wall, computer and more). Line frequency was a time standard.

[valhalla360]

Originally Posted by s/v Jedi

Surprised nobody came up with the reason for raising the voltage up to the maximum all over the world. It’s simply to push as much power through the same cables

I alluded to that when I mentioned that it started at 110 went to 115 then finally 120...

Additionally, I believe, that power companies will push the upper bounds of the tolerance during peak demand period (hot summer days for example), to maximize the available power.

[Mauruuru]

The actual service voltage for US residential use is 129/249VAC 60 Hz If you look at a domestic AC or heat pump it will be rated for 230 V AC single phase. That is the nameplate rating for the compressir motor. In aboat you will have a 120 V AC compressor unless your into Yachts in which case you probably have 120/240 V service as well as similar rated equipment.
The reason is simple P=VI in a single phase circuit. For given power requirement doubling voltage halves current requirement and therefore wire size

[Mauruuru]

Sorry fat fingers 120/240 V AC

[captainwd40]

My 2 cents ...... from an electrical engineer stand point.

220 volts is better than 110 volts because it only requires half the amps which is important when it comes to wiring and batteries.

Cheers!

[skenn_ie]

12/24V Batteries. 14/28V electrics, as that is what the buss will have on it when chargers/alternators are running in maintenance mode

[whazammo]

Must be a bunch of yougsters here.... All new US boat panels and dock power outputs have been 120/240 for a long time now. and, if metered run almost within a few percentile of that rating

years ago 110/220 brought us in from the 1950's or so, it changed about the time te polarized outlets and plugs came out (big/little).

[Cadence]

Originally Posted by whazammo

Must be a bunch of yougsters here.... All new US boat panels and dock power outputs have been 120/240 for a long time now. and, if metered run almost within a few percentile of that rating

years ago 110/220 brought us in from the 1950's or so, it changed about the time te polarized outlets and plugs came out (big/little).

I knew I recalled plugs going in either way, prior to the ground lug. 15A fuses to 20A was probably about that same time.

[EngNate]

Nominal is the keyword. The US grid is 120/240, or 120/208 3-phase but people reference various values because we remember and repeat what we see, and we see this just about exclusively on the labels of our appliances - 110, 115, 117, 120, even some 130, and 220, 230, 240. The standard is for the grid, but there's no signs hanging off the wires. The makers determine the design voltage and voltage ratings of their products, and they may vary from the grid standard for different reasons. By-and-large, all electrical and electronic devices operate as designed within +/- 10% of design voltage. At least for '120' stuff, the distinction is trivial in practice. 'One-something' means that lower voltage in the US, 'two-something' the higher one. That's as much definition as needed for most purposes. I'm going to venture that the most commonly referred term is 110/220, and the reason is simple: "one-ten" has one fewer syllable.

Here is a consideration where it can make a difference: In the US and Canada most marinas get 3 phase 120/208 power. Only small operations, docks in residential complexes, and legacy installations have 240. The typical range I observe on 3PH docks is 197-210. Motors are commonly available with voltage ratings of 220, 230 and 240. 240 +/- 10% = 216-264; 230 = 207-253; 220 = 198-242 A 220V motor will be happy on 208 power, a 240V won't, 230 is probably the best choice for a larger motor if a choice is available. However, if it's practical to use a low voltage motor(s) that is actually better yet because the 120 side is 120 in both single and 3 phase.

An explanation how 3 phase and single phase voltages add up would probably be helpful here, but needs some graphics and will have to wait...

[cyan]

Originally Posted by captainwd40

My 2 cents ...... from an electrical engineer stand point.

220 volts is better than 110 volts because it only requires half the amps which is important when it comes to wiring and batteries.

Cheers!

I'm a little fuzzy on the "batteries" part. Why would DC battery current be different for 220V vs 110V, assuming an inverter with the same power rating in either case?

[theBigKahuna]

Being a 'newbie', I appreciate the historical background! Having sailed over 40 yrs, but just upgrading to a 40' cat, I'd told my friends "the sailing is easy... it's everything else... bigger the boat... the more systems". Personally trying to get my head around the electronics (110/220 being just one learning lesson).

[KP44]

We currently (pun intended) have a grid of 120v above and below neutral. It started at 110v and that's where the 110 came from. The grid is nominal at 120v. So we have 120 and 240. But people commonly call it 110 and 220.