What were the low voltages of the 19th century

Thomas Edison opened his Pearl Street power station on Sept. 4, 1882 which provided DC power up until 2007.
What does that mean? What kind of voltages were used at the dawn of electricity distribution?


DC "low" voltage levels:
0.7V Nominal voltage drop on normal silicon diode or similar semiconductor junction
0.8V Voltages from 0V to 0.8V are considered to be logic 0 on TTL logic IC inputs
1.25V NiCd, NiMH battery cell nominal voltage
1.5V Carbon and alkaeline battery cell nominal voltage
1.6V The voltage you normally get from a fresh alkaeline battery cell
1.8V Quite commonly used very low voltage digital circuit operating voltage (many CPU cores)
2V Lead acid battery nominal cell voltage
2V Voltages from 2V to 5V are considered to be logic 1 in TTL logic IC inputs.
3V Lithium battery nominal voltage
3.3V Low Voltage Logic Threshold Levels (LVTTL) logic circuits operating voltage
3.6V Typical voltage used to power cell phones (either from NiMH or Li-Ion battery pack)
4.5V operating voltage for many small electronics gargets powered from three batteries
5V TTL logic circuits operating voltage
6V operating voltage for many small electronics gargets powered from four batteries
9V Commonly used battery voltage
10V Normal control voltage limit in 0-10V and 1-10V analogue control systems (light dimming and industrial use)
12V Car battery nominal voltage
13.8V the voltage you expect to get from car 12V power when car motor is running (charging battery)
24V Truck battery.
24V Automation systems most common nominal voltage used for logic signals and and current loop powering
24V common standard input voltages in Avionics and Defense applications
28V Maximum battery charging voltage for 24V battery system (for example batteries that power automation systems).
28V common standard input voltages in Avionics and Defense applications
36V Battery voltage used on some electric golf carts, electric scooters, electric bikes, high power cordless tools etc..
42.4V Voltages must be less than or equal to 42.4V peak/60V dc to meet safe limits and to be Safety Extra Low Voltage (SELV).
42.4V Hazardous Voltage is a voltage exceeding 42.4V peak or 60V d.c., existing in a circuit which does not meet the requirements for either a Limited Current Circuit or a TNV Circuit.(IEC 60950)
48V Battery backed up -48V voltage is used on telecom systems for powering telephone exhanges and other telco equipment. The normal service voltage range for the -48 Vdc nominal supply at interface “A” shall be -40,5 Vdc to -57,0 Vdc according to ETSI EN 300 132-2
48V Some data centers use 48V DC to power servers (battery backup easy)
48V Phantom power feed for microphones in audio mixers most often uses +48V phantom power voltage
48V some automation systems use +48V power for equipment and I/O (electrical power distribution)
50V Work on energized circuits or apparatus below that voltage requires no “Hazard/Risk Evaluation.” NFPA 7OE
60V Voltages must be less than or equal to 42.4V peak/60V dc to meet safe limits and to be SELV.
60V Hazardous Voltage is a voltage exceeding 42.4V peak or 60V d.c., existing in a circuit which does not meet the requirements for either a Limited Current Circuit or a TNV Circuit.(IEC 60950)

48v phantom power feed for microphone circuit is standard for many people who hook themselves up to a bioamplifier. Not particularly safe to hook oneself up to such a circuit but people have survived it.

Homemade ekg leads and aloe vera gel and using a filter to suppress the signal from electrical service is what one experimenter did to analyze her own ear for a tinitus episode.

Quote: Pacomartin

...
12V Car battery nominal voltage
13.8V the voltage you expect to get from car 12V power when car motor is running (charging battery)...

I think 14.8V is nominal for the power in a car with the motor running.

I recall that the limited distance DC can be transmitted is what lost it the race with AC. Who was still buying power from the Pearl Street generation plant?

For an automotive alternator, 13.8V is the normal minimum, 14.2V is the normal maximum, some cars use 15V and in some conditions charging voltage might be as high as 15.8v.

http://www.aa1car.com/library/charging_checks.htm

Quote: Ayecarumba

I think 14.8V is nominal for the power in a car with the motor running. I recall that the limited distance DC can be transmitted is what lost it the race with AC. Who was still buying power from the Pearl Street generation plant?

To be precise, you need high voltages to transmit long distances. The technology of the 19th century was incapable of transforming Direct Current into high voltages for long range transmission, and then transform it down to usable voltage levels for homes and businesses. It was much easier to build transformers with Alternating Current. The first transmission lines to go over 20 miles used 11,000 volts and were AC.

Edison envisioned DC power plants at roughly 1 mile intervals, but at the time the primary usage would have been lighting.

The Niagara Falls AC generation system was developed in 1895, and the modern form of high-voltage, direct current (HVDC) transmission uses technology developed extensively in the 1930s in Sweden (ASEA) and in Germany. In those four decades a great deal of infrastructure was already built with AC, so it was not very feasible to switch.

China, with it's massive population in one part of the country, and huge deserts where giant electrical generation plants can be easily developed is investing heavily in high voltage DC. Wikipedia has a lit of HVDC projects around the world.
https://en.wikipedia.org/wiki/List_of_HVDC_projects#North_America

Quote: Truly Trivial

IThe last of the Consolidated Edison (the New York city electrical utility) DC power lines was severed and replaced in 2007 -- over a century after alternating current became the prevailing electrical technology. Moreover, there are still a number of DC power systems in place in New York -- the NYC Subway's third-rail power supply chief among them.

Con-Ed didn't begin the project to finally deprecate all DC consumer power transmission until 1998, and it took nine years to finally convert all the DC lines to AC. In many cases, those DC customers still have DC lighting and power inside their homes and shops, but Con-Ed converts the AC line-power to DC with an on-premise rectifier. In the early 20th century, many taller building were designed with DC elevator systems that are still in service. Several hotels were designed with DC power stations in their basements to run their lights and appliances.

One of the major drawbacks of DC power --besides an inability to efficient transmit power over long distances -- was a lack of easy voltage transformation. Phased AC power lines can run to a transformer that steps down 440-volt current to 220-volt appliance-grade power, and then your local panel box can step that down to to the 110-volt lighting and outlet current. DC installations required wholly separate lines from the power plant to deliver different voltage currents, and retrofitting buildings designed around these DC limitations is prohibitively expensive. Thus, New York has a startling number of buildings with DC-powered elevators and and central light systems running alongside later-installed AC electrical systems.

Thus, while the last New York DC power line was cut in 2007, DC power is alive and well in the Big Apple. That's not just some long-tenured tech, it's an immune to obsolescence example of the Truly Trivial.

Seeing that some electrical installations are over a century behind the times, makes it easier not to laugh at people who still use WinXP, or those who go online through AOL.

Third rail must be DC, even in modern systems. Overhead is more popular with post WWII designs.

Some of the elevators in NYC are a century old and would cost a fortune to convert from DC to AC.

The Cortland Street bridge in chicago opened in 1902


Hudson tunnels in NYC opened in 1908, and are still vital to rail traffic under the river.

Quote: Pacomartin

Some of the elevators in NYC are a century old and would cost a fortune to convert from DC to AC.

Many people have a PC that works perfectly ok with XP. It not only might work for many more years yet, but most of these are impossible to upgrade to Win7, Win8(.1) or Win10.

Sure, the cost of a new PC is much lower than that of even a cheap elevator in a three-story building, but it could be a considerable cost to lots of people.

:)

Elevator repairmen and installers make between
$35 and $50 an hour depending on where they
live, And they are always busy. Good profession
for a young guy to get into. Elevators will always
be here.