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Friday, 9 October 2020

Why are we sticking with AC?


Should houses and offices have DC distribution cabling?


In the beginning there was DC

In the 1870's, Thomas Edison developed the DC (Direct Current) generator and built the first electrical distribution system.

The problem was that the distribution system had to be at a non-lethal voltage as the voltage could not be changed after generation. This led to high transmission losses as loads increased resulting in a power station being required every few kilometres.

And then there was AC

Nicholas Tesla developed the AC (Alternating Current) transformer which allows the voltage to be changed. This allows high voltage transmission over large distances then the voltage is stepped down for local non-lethal use.

Th
e AC system was adopted after a protracted fight between Edison and Tesla. Until the 1920's all domestic appliances were designed to run on AC – 250V in the UK, 110V in the USA and similar across the world. House and office wiring has remained this way ever since.

And then there was Radio

The thermionic valve was invented and this led to domestic radio set. Radio receivers are DC systems so AC to DC convertors were built into the sets.

This led to record players, television and then to home computers, both DC systems relying on AC to DC convertors.

And then there were portable computers

This is where the explosion of DC devices began.

The demand for portable computers led to great improvements in rechargeable battery technology which in turn led to a much wider use of portable devices.

This also has led to a great improvement in the performance of AC to DC convertors and also to better DC to DC convertors.

A selection of my chargers

 


 My AC powered DC devices

Device



Device


Television

2


Boiler

1

Radio

2


Power Drill

1

DVD Player

1


Mini power drill

1

Video Recorder

1


Fairy Lights

3

Computers

2


Shaver

1

Computer Monitors

2


Under Cupboard Lights

3

Printer

1


Ceiling spotlights

1

Mobile phone chargers

2


Cupboard Lights

1

4G WIFI Hub

1


Doorbell

1

Internet router

1


USB Charger plug

1

Telephone system

2


Washing Machine display

1

TV Tuner

1


Cooker Display

1

TV Ariel booster

1







Total

35

My AC devices that could be DC

Many of these are available in DC rechargeable battery powered versions.

Device



Device


Fan Heater

2


Washing Machine

1

Oven

1


Iron

1

Extractor Fan

1


Vacuum Cleaner

2

Toaster

1


Paint Stripper

1

Kettle

1


Power Drill

1

Refrigerator

1


Soldering Iron

2

Carving Knife

1


Lawn Mower

1

Mixer

1


Hedge Trimmer

1

Hair Dryer

2


Strimmer

1

Jig Saw

1


Sander

1

Circular Saw

1


Angle Grinder

1




Total

26

Some of the power devices are are possibly better as AC powered.

Mini generation devices get added to the system

To complete the picture, many houses now have generating devices such as PV solar panels and wind turbines which can feed back to the AC supply. Some also have backup batteries.

So we have a mishmash of systems

We now have multiple devices individually converting AC to DC, each with power losses and using up material resources. We also have some houses with DC to AC convertors. With modern electronics, DC to DC conversion is relatively simple and inexpensive.

So, houses and offices should have DC distribution cabling

It is time now to develop a standardised domestic/office DC power Distribution System from which all our devices can be powered without a multitude of costly and bulky AC/DC convertors. They can be powered from the local AC distribution system via a single AC/DC convertor.saving energy and materials

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