I have recently been dabbling in Pyrography (wood burning) and was using a battery charger to power my nichrome pen. as the power supplied is not that strong, i got hold of an old computer UPS (240v, 500va) i removed the 6v battery and connected the battery terminals to a 3inch long piece of piano wire. The wire glowed red hot so the power is a bit to much for the nichrome i want to use.
Question (1): Can i somehow reduce the power at the battery terminals?
(2) Will a dimmer switch between the wall socket and 240v Ups input reduce the power supplied at the output battery terminals.

Thanks

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Dreams contain the seed of success..... (if you manage to wake up.)

Using the PC psu doesn't sound like a satisfactory answer, definatly not with a dimmer switch.

I would have thought you could get a proper transformer to provide the correct power. Does the nichrome pen have a power rating?

i have a variable power supply but i like to experiment with things and recycle old thigs for other uses.Working with tools that i made myself gives me more pleasure than just working with off the shelf tools.
the nichrome pen is homemade and the nichrome tip came from an old washing machine heating element.
Maybe it's a stupid question, As i know next to nothing (but would love to learn)about electricity i would love to know in simple language why the dimmer switch is out of question.

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Dreams contain the seed of success..... (if you manage to wake up.)

Haven't you got any old radio bits you can adapt, we used to use something like the volume control knob to dim a torch bulb and reverse.

I'm going back 50s here and the memory is not that good.

It was like a round disc with segments, then a brass bit made contact, the dimmed as it made contact with each segment.

Stoday's probably the best man, when he wakes up around 3am

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A dimmer switch wouldn't be a good idea as they are
a) designed for lighter loads - i.e. 100w
b) the electronics are quite delicate

as suggested above a simple volume switch would work better but I would use it between the PSU and the pen

What you have to remember Talkingcars is Rotciv, is the mad professor that finds all these bit of scrap in skips, then makes all sorts of brilliant and practical gadgets.

You must look through the showcase gallery.

Just as well they don't have the HSE in Malta mind

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thanks for the advice guys, I will try to locate a volume switch and try it out. If i survive i will let you know the results
Although my contraptions may not be CE certified, the jolts that tripped my circuit breaker were not coming from them but from the Taxman

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Dreams contain the seed of success..... (if you manage to wake up.)

No - the wire glowed red hot because you passed too much current through it.



If you reduce the voltage to the extent that you can connect a 3" piece of wire across it and not get enough current to heat the wire then your pyro pen won't get hot, will it.



When it fails, or destroys the UPS it will reduce the output voltage to zero.

Which is probably the safest voltage for you to work with, given your lunacy.



http://www.kevinboone.com/electricity.html

http://en.wikipedia.org/wiki/Electricity



It's not a stupid question.

What is stupid is the answer "yes it is OK for me to fiddle around with DIY electrical tools and power sources which can melt wires even though I don't have clue about even the most basic relationships between voltage and current".

Dimmer switches work by chopping the input either on the leading or trailing edge of each half cycle, thus lowering the RMS voltage.

A UPS will contain, basically, a switch-mode PSU which will see the chopped waveform as a poor quality supply, and will do what it's supposed to do, which is to adjust itself so that it continues to provide the same output, until it gets to the point where the input voltage goes out of range when it will shut down.

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I'm sorry - I can't come in to work today, the voices are telling me to stay at home and clean the guns.

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Thank you Ban-All-Sheds for the very informative links you provided in your post as i'm going through them and starting to understand the basics.your info about how the ups works .
i can understand that a certified pro like yoursel is appalled at the thought of a greenhorn like me dabbling in electrics but i can assure you that eccentric i might be but i' not in the lunacy stage yet as i make doubly sure that no other persons or property are endangered by my actions.And in my professional work as a stone mason i take every precaution to safeguard the safety of myself and my employees when working with the 3 phase macinery necessary for my work.
Being inquisitive and wanting to learn about different materials and processes, in my humble opinion doesn;t automatically render you a lunatic.

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Dreams contain the seed of success..... (if you manage to wake up.)

Quite right Rotciv, I often wondered how we all survived

I mean did they have a method statement and HSE looking over the shoulder when they invented the wheel.

And just imagine the paperwork for the first plane, it would never have got out the hanger.

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If they had today's regulations.by the time the fist planes engine was approved for decibel ratings and emissions the pilot would either have been deaf with old age or dead from smoking.

_________________
Dreams contain the seed of success..... (if you manage to wake up.)

What you need is an old valve heater transformer. They had 6.3V outputs of several amps. Real transformers are far more robust than the electronic voltage convertors you get nowadays.

Find one at a local ham radio junk sale or look around here: http://www.junksale.co.uk/

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I should be dead; I've cheated the Grim Reaper yet again by surviving my third heart attack in June.

Thanks Stoday. would this transformer look something like the pic attached? and in what appliances was it used Ex: radios,tv's etc

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Dreams contain the seed of success..... (if you manage to wake up.)

Yep, transformers like that only larger.

From scrap electronic gear, normally industrial/commercial. Radios and TVs generally had the valve heaters wired in series to avoid the cost of a heater transformer.

You can, of course, buy a new 6V or 12V toroidal transformers from ebay for £10 or so.

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I should be dead; I've cheated the Grim Reaper yet again by surviving my third heart attack in June.

Rotciv - you shorted the output of a half-kilowatt power supply.

That is not the act of a sane or sensible person.

If you want to learn about things by trying any daft idea that occurs to you, without making any attempt beforehand to understand the implications of trying it, then be prepared to join the long list of people who were killed and injured by experimental acts in the brave old world that you and Scruff seem to think was better.

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I'm sorry - I can't come in to work today, the voices are telling me to stay at home and clean the guns.

.