Just Need a Bit of Help...

These may help:

http://www.ehow.com/how_4487559_build-transformer.html

http://en.wikibooks.org/wiki/School_science/How_to_make_a_transformer

By the way, Del - GA

Quote "I also dont get why you can have an adapter and the primary coil can be made of like hair thin wire and have thousands of turns but mine had like.... fairly thick wire and 400 turns and it melted"

Yours melted because it did not have the resistance and reactance that the fine hair wire gives you with thousands of turns. You basicly had a short circuit.

Z_i=R_w+jωL+Z_l Therefore I_i=V/Z_i=V/(R_w+jωL+Z_l)

With respect, stop w**king. How do you think that could possibly help the OP?

Please don't preface an insult by saying: "with respect"

some decorum, please.

RedFred's answer was probably just influenced by his enthusiasm for the subject, not out of a motivation to patronise others. I appreciate that his response was more technical than necessary, but at least I learnt something - which is why I'm here.

Regards,

TinTin

Study Faraday's Law to see

The hair thin wire will have more resistance and hence will limit the current whereas the thick wire won't.

Assuming you are working on DC try to put a resistance in series to control the current to be a proper electromagnet. When my kid was doin it, I just advised him to but a normal torch bulb in series, but in case you want a better one, get some variable resistor. Else it will not only heat up the coil, but may spoil your power source too.

Remember for DC the L is virtually non existant and only the wire resistance (and the resistance of the source) is what is controlling your current.

The first thing is that by having several thousand turns of a light gague on the primary, creates a high resistance. Secondally a transformer requires an alternating current on the primary, this produces a back EMF (electro motive force) which in effect reduces the line current of the primary winding the internal resistance also limits the line current as well.

By reducing the No of turns and increasing the conductor size as you have done, it goes the other way, less turns less back EMF, less internal resistance, means higher current and more heat produced through Amps squared x resistance losses.

You are using AC supply arent you?

Also check the secondary winding of the transformer, that it is not shorted out.

One final thing that you should do, use fuses of the correct sizes on both primary and secondary.

Transformers are a science in themselves, of course you have a line transformer on a car DC ingnition but this is switching off and on several times a second creating an alternating dc supply.

In regard to the 1.5 v verses 9 v battery, i would think that the 1.5 volt battery had a higher MV.A Ratting than the 9 volt battery, in other words the 9 volt battery did not have enough energy to heat the winding.

If you are just trying to make a DC electromagnet, first find out what the current ratting of conductor you are using, then by using ohmns law calculate the required resistance you require so that you dont draw excess current, you probally want to de-rate the conductor dont run it a max unless it is for a very short time only.

By knowing the internal resistance that you require you can then calculate the meters of cable required to be wound, so you dont cook it.

May The Force Be With You

Batteries produce DC. Transformers use AC. The sine wave motion cuts the lines of flux to induce a current. Did I miss something?

Hello Guest

Back to your project; Heavier gauge wire up stands more current but you need high enough inductance to keep your resulting prime impedance high enough; this is why your purchased transformer has thin wire and more turns in the prime coil while the secondary has heavier gauge wire to up stand higher current.

Safety precautions: wear glasses, have a 1 amp fuse in series with your starting project, try not to be alone in case you need help, use a wood table or work bench and be careful

Let's start with basic concepts:

1 Resistance is the opposition offered by any matter against the flow of Direct Current, the unit of measure is the ohm, Kohms (1000 ohm or Megohms 100000 ohm), and this opposition is responsible to transform the electric energy in to heat.

Some metals offer low resistance (less than 1 ohm per inch) to current therefore are considered conductors where silver has the first place among the elements, cooper and gold are good too but cooper is more often used because it is abundant and relatively inexpensive.

Plastics, dry paper, rubber, ceramics offer high resistance, it is so high that most meters are not able to measure it therefore it is considered infinite.

In between are the resistors like carbon, graphite, iron, actually those are the most common materials.

R=E/I Where R for resistance, E for voltage and I for current

2 Direct Current or DC is the quantity of electrons flowing in one way in a given moment, the unit of measure is the Ampere but DO NOT measure current unless you open the circuit to connect your Amp meter in series.

I= E/R

3 Alternating Current. Same as DC only that changes polarity at a given frequency, in the USA the frequency at your domestic AC power plug is 60 cycles per second.

4 Voltage is the pressure field applied to the electrons to move, the unit of measure is the volt.

E=I.R

5 Power is the amount of energy transformed in a given time. The unit of measure is the Watt for electrical power.

This means that you can do the same job using high voltage times low current like in the motor of your air conditioner or do the job with low voltage times high current like in the start motor of your car.

W= I.E Where W for power

120V*5 Ampere = 600 Watt at your air conditioner motor

12V * 50 Ampere = 600 Watt at your car's start motor.

The grater the current the heavier the wire gauge is needed to allow a great quantity of electrons flowing.

6 Inductive Reaction or chock. It is the opposition of the coils to a given frequency and is caused by a 90 degree delay offset against current respect to the voltage; this opposition to the flow of current does not generate heat.

7 Capacitive Reaction. It is an opposition caused by a 90 degree delay caused by electric capacities or capacitors to the voltage in a given circuit; this also does not generate heat. This is opposed 180 degrees to the Inductive reaction (In fact the frequency tuning occurs when the Inductive reaction and the capacitive reaction are vector ally equal but in opposite directions, they both null the opposition), the unit of measure is the ohm.

8 Impedance. It is the resulting vector of opposition from a combined circuit of resistance, Inductance, and capacitance, the unit of measure is the ohm.

9 Inductance Is the capability of a circuit (typically a coil) to transform electrical energy in to an electromagnetic field, the unit of measure is the Henry.

10 Primary to Secondary turn's ratio. Voltage is directly proportional to the turns ratio while current is invert ally proportional.

11 Core or K. It is the inductive properties of a ferromagnetic core to increase the inductance of a circuit at a given frequency; laminated iron is normally used for low frequencies like audio or industrial power while ferrite or grinded iron are normally used on medium to high frequencies audio, AM, FM, VHF. No core (air core) is used at Ultra High Frequencies UHF.

Guest,

Fewer turns of thicker wire for a primary on a core designed for 50 or 60 Hz would be for a low Voltage AC input. If your other winding was lots of fine wire of many turns you should have used that for primary.

If the core was ferrite you could used a higher voltage at a much higher frequency or dc pulses to transfer power to the secondary.

It would be good for you to know how much current can be applied to a certain size wire of a chosen length.

Also you NEED to get a Fused Variable Autotransformer. (Also know as a Variac)

In the old days we made transformers from a bundle of shellacked nails and wires from old radio transformers.

Little motors from magnets thumbtacks wire and bent paperclips and wooden dowels and straightpins and a drycell battery. And some using electromagnets.

Made rectifiers by putting a piece of foil on a lightbulb and coating it with a few coats of parafin and using a Model T Buzzbox connected to the foil and lamp base polarized so the spark would jump to the foil to burn holes in the glass for the electrons to pass from the filament to foil when the light was energized enough to produce thermionic emission to rectify AC for our dc projects.

We studied the situation to prevent disappoinment and waste of our hard to find materials.

Jon