Melting a nail with high currents

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Hi.
I melted a nail using a transformer with 500 windings on the primary and 5 on the secondary and 220 V input voltage, but I can't make the numbers work out. I measured the output voltage to be around 2 V, which makes sense.

Trying to measure the resistance of the nail directly with a multimeter yields around 6 Ohms, which appears be way to high. With a different power supply I can get 10 A across the nail at around 1 V, which leads to 0.1 Ohms, but this would still only lead to 20 A with the transformer, which still seems way too low to make it melt.

What's wrong here? And why is the resistance measured with the multimeter so far off?
 
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greypilgrim said:
What's wrong here? And why is the resistance measured with the multimeter so far off?
Was the multimeter calibrated? Did it have lead resistance and contact resistance? Measure it by shorting the test probes, and check the zero calibration.

What is the length and diameter of the iron? nail ?
What is the length and diameter of the copper? wire, used for the secondary winding ?
 
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The diameter is 4 mm and the distance between the contacts of the secondary is 5.4 cm. Using the resisitivity of iron, I get ##4\cdot 10^{-4}\enspace\Omega## , which seems about right.
I also found a different isolation transformer with an input ammeter that showed 3 A at 200 V, so the output current should be in the hundreds A, which makes much more sense.

First I just pushed the probes of the multimeter against the nail, which gave very unstable values. Then I used crocodile clips. Could it be that most of the resistance is due to the contacts? Should I maybe file down the surface of the nail?
 
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greypilgrim said:
Could it be that most of the resistance is due to the contacts?
Yes.

Most DMMs just aren't designed to resolve very low resistance. You would probably be better off using it to measure current, at a high current level, and then voltage and calculating the resistance.

Read about "4-wire ohmmeters" or "kelvin connections".
 

1. How does melting a nail with high currents work?

Melting a nail with high currents works by passing a large amount of electrical current through the nail, causing it to heat up and eventually reach its melting point. This process is known as Joule heating, where the resistance of the nail to the electrical current causes it to generate heat.

2. What type of current is needed to melt a nail?

To melt a nail, a high amount of electrical current is needed. This can be achieved through either direct current (DC) or alternating current (AC). However, AC currents are more commonly used as they are easier to control and can reach higher levels of current.

3. How much current is required to melt a nail?

The amount of current needed to melt a nail can vary depending on the type of nail and the conditions it is being melted in. Generally, a current of at least 100 amps is needed to melt a nail, but this can go up to several thousand amps for larger nails or nails made of more resistant materials.

4. Is it dangerous to melt a nail with high currents?

Melting a nail with high currents can be dangerous if proper precautions are not taken. The high levels of current can cause severe burns or electrocution, and the melted nail can also release toxic fumes. It is important to have proper training and safety measures in place before attempting to melt a nail with high currents.

5. What is the purpose of melting a nail with high currents?

Melting a nail with high currents is often used in scientific experiments or demonstrations to show the effects of Joule heating. It can also be used in industrial processes, such as welding or metal casting. Additionally, it can be a fun and educational way to learn about electricity and its effects on different materials.

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