The most relevant option to measure the diameter are devices such as a caliper and a micrometer. These devices allow you to measure the diameter as accurately as possible. To do this, you will ne a wire and a micrometer
Fig. 3: Wire and micrometer
Consider an example of determining the cross-section for a single-core wire (Figure 4).
Fig. 4: Measuring with a micrometer
To do this, the lock B is mov to the open position. The handle of the home owner data is unscrew to such a distance that the wire easily fits into the space between the probes A. Then, using the handle G, the device is screw until the ratchet operates. After this, the readings are record on all three scales at point B.
In this example, the diameter is 1.4 mm, therefore, to calculate the cross-section, we ne S = 3.14 × 1.4 × 1.4 / 4 = 1.53 mm2. The same procure for determining the cross-section can be perform using a caliper.
The advantage of this method is the ability to measure any how to promote a website to the top of yandex: instructions checklist conductor, even if it is already install and us to power some electrical device. The main disadvantage of the method is the high cost of the devices, naturally, it is completely impractical to purchase them for a couple of measurements.
By diameter using a pencil or pen
This method of determining the cross-section is bas on the fact that the wire has the same diameter along its entire length. Take a regular pencil, pen or felt-tip pen and wind the wire in a spiral. To eliminate the thickness of the insulation, it must be cut along the entire length. The rings must be locat as tightly as possible; the italy numbers the space between the rings, the lower the accuracy.
Fig. 5: Determining the cross-section with a pencil
Since all wires have the same thickness, to determine the diameter of copper wires, measure the length of the entire winding and divide by the number of turns. In this example, D = 15 mm / 15 turns = 1 mm, accordingly, using the same calculation formula, we get a cross-section S = 3.14 × 1 × 1 / 4 = 0.78 mm2. Note that the more turns you make, the more accurately you determine the cross-section.
It is worth noting that the advantage of this method is that only improvis means can be us to determine the cross-section. The disadvantage is low accuracy and the possibility of winding only thin conductors. In the example, a relatively thin wire was us, but the distance between the turns is already visible. Because of this, the accuracy leaves much to be desir, of course, it is impossible to bend aluminum wire in this way.
By diameter using a ruler
Let’s make it clear right away that for measuring with a ruler you can only take a relatively thick wire, the smaller the thickness, the lower the accuracy. The diameter of the vein can be determin with a thread or paper, the second option is the most preferable, as it provides greater accuracy.
Fig. 6: Preparing paper for measurement
Tear off a small strip and fold it on one side. Thinner paper is preferable, so there is no ne to fold the sheet several times.
Figure 7: Wrapping with paper
Then the paper is appli to the wire and wrapp around the circumference until the strip touches. At the point of contact, it is fold a second time and appli to the ruler for measurement.
Figure 8: Measuring with a ruler
Using the obtain circumference length L, the diameter of the vein D = L / 2 π is found, and the calculation of the cross-section is perform as shown earlier. This method for determining the cross-section is well suit for large aluminum veins. But the accuracy in this method is the lowest.
