Automotive Industry migrates to 48V electrical system

Ok, so 3-phase can be seen as a merry-go-round, observed from three positions, 120º apart. Still the same merry-go-round, yet called 3-phase.

 

My example was just that, an example of a single sinusoidal wave, and how you can view it from different viewpoints. 3 phase has 3, separate sinusoidal components, 120 degrees shifted from one another carried on a minimum of 3 wires. If I remove one, the other 2 remain - they are independent.

In split phase, if I remove power to the single phase, both legs of the split phase go away as they are 2 sides of the same coin. To that end, 3-phase would be 3 merry-go-rounds stacked on each other, each one 120 deg different than the other, each merry-ground being a single phase.

 

You are answering your own question. Here it is real simple and easy to tell Single, 2, 3, and yes there is 4 and 6-phase, count the number of Cores used on the secondary, not to be confused with Taps on a single phase core. Example here is a 3-phase Transformer.



Here are the two 2-phase circuits.



Last up is Single Phase USA.

 

This is all correct. I've been designing & testing hybrids & EVs for 18 years for various OEMs and suppliers.

 

The Phone companys have been using 48VDC since the development of the heat coil granted its a _48VDC system but huge amperage can be used with less voltage drop
most switching and transmission equipment in phone offices dont like under voltage infact it does damage to them so i can see them wanting to use 48vdc
its a more stabil platform
the on-board computers will be more stable the wire gauge can be smaller and deliver the same amperage heres the problem if youre going to try to do this all electric the batteries are huge
and heavy this will doom the 48vdc car

 

What does voltage have to do with the size of the battery? I have on my desk a 3 V battery, a 9 V battery, a 12 volt battery. Now, tell me how big they are.

 

You just made all that up and have no clue what you are talking about.

 

voltage has nothing to do with it its the amps that mandate Battery size

 

so i made up 10+ yrs installing switching and transmission equipment inside central offices have you ever been in one ? have you ever seen a Battery string they use or the size of them ?no? well then i suggest that you go ask a centurylink or one of your local phone technicians about them
what a stated in my reply was my own opinion in relation to my experience no need to call me a liar

 

It is battery type, voltage and capacity that determine size and weight. .

 

Yep professionally for 40 years as an engineer. Even write the Standards and Practices for Telecom. -48 VDC is a COMPROMISE voltage. Just high enough voltage to facilitate and control reasonable audio and voltage loss on transmission equipment, but PRIMARY driving factor is all the electrical codes change to the expensive side when you cross the 50 volt line. No fuses, grounding, or any equipment needed outside the plant for life and property safety. 48 volts is also safe for your idiot kids to touch and suck on the phone lines inside the house without injuring them or setting your house on fire. It was a Compromise to save billion$ in equipment and litigation/liability co$t. In other words all about money.

To have any equipment certified by Telcordia (formerly BellCore) in a Telco office must operate from 42 volts to 60 volts, the operating range of a 48 volt battery. The Telco operational voltage is anything but STABLE. Needless to say all those processors you mentioned out on the network operate at 3 to 12 volts just like your laptop and cellphone.

Other voltage used was 130 VDC to carry power on long reach T1 lines to power repeaters which has pretty much all been junked and replaced with fiber. None of that ever went into CPE location.

 

Just for the record....... it ain't so easy to "tap up" into a battery stack.......... like one 12v battery up in a 2 battery (24v) stack............ what happens is if you drain down the bottom (12v) battery the alternator cannot fully recharge the bottom battery thru the top (more charged, higher impedance) battery.......... we tried that years ago on a Military surplus M-37 weapons carrier (3/4 ton truck) and could never charge the stack fully. Eventually we bought a 24v to 12v (step down) converter which solved the problem. We used the same converters on a "deuce & 1/2" off road tanker project to run all the standard 12v accessories the firemen wanted........ I think they were from Samlex and they were small, fairly inexpensive and pretty efficient.........

73
Mike, K1FNX

 

This is not going to happen, it was proposed years ago, but never happened and probably won't.

 

There are VERY good reasons for introducing legislation to limit automotive power to 12 volts: 1) The amount of electronic distractions to drivers, even now, is too large. Built-in power limitations serve to keep our highways safe. 2) Power taken from the engine for various needs already requires a large, heavy, and expensive alternator and storage battery system. Increases in power will demand both of these systems grow, regardless of voltage, and batteries even at their best, are dangerous. 3) Higher primary voltage will almost guarantee a fire in conjunction with most accidents, as increased fault current will be delivered, even before fuses blow. 4) Voltages above 24 pose a risk of shock to humans and animals, 12 does not. 5) Increasing the number of cells in the storage battery will reduce its reliability and increase cost. 6) The costs of implementing this change, and mitigating the inherent problems, will drive the price of vehicles higher, and eventually also the used vehicle market - those who can now only afford a modest car would be forced to walk, ride bicycle, or become dependent on government for transportation, widening the gap between the rich and poor. Needless to say, raising automotive voltage to 48 is a terrible idea...

 

You forgot dogs and cats living together, sea level rise, and the children, who are our future.