Tue Oct 10 21:12:02 CST 2023
Spark testing is used to detect insulation defects in insulated conductors. Spark testing machines are usually used in core wire extrusion or core wire twisting sections. Sometimes they are also used in total twisting sections. Generally, shielded cables (braided wire, aluminum foil outward) are also tested for defective points when pushed out. The basic method is to apply a voltage between the electrode in contact with the tested object and the grounding conductor. If the insulation medium is poor (such as too thin or a part is missing), The applied voltage will generate an arc on the grounding conductor, thereby activating the indicators connected to it (such as buzzers, lights, counters, etc.); In spark testing, there is a dangerous high voltage, so the relevant equipment must be completely grounded. Generally, testing machines can use AC or DC voltage, while AC can be used at different frequencies. For safety reasons, the testing current is usually limited to a level without fatal danger.
The conductor continuity of wires and cables is a key characteristic
Unless otherwise specified, conductor conductivity shall be tested using a d-c voltage of 100V or lower. For manual conductivity testing, a 9V battery shall be connected in series with a visible or audible indicator. The insulation at both ends of the conductor shall be removed, and the conductor shall be separated. When using an automatic tester, each conductor shall be fixed to a testing fixture separately. If manual testing is used, all conductors at one end of the wire are usually connected to the same testing end, Apply voltage to both ends of each conductor in sequence. Use an indicator light to indicate whether the circuit is conducting or not.
The resistance of each conductor in wires and cables is an important characteristic. However, the measurement of conductor resistance is usually only conducted during sampling inspection of the finished product, The sample is calculated based on the unit of wire (such as shaft) at the time of shipment. If the cable contains a large number of conductors, the conductor can also be sampled for measurement. Unless otherwise specified, the conductor resistance measurement is conducted at 68 ℉ (20 ℃). The temperature core is in accordance with ASTMB 193. The resistance changes with the length of the cable. The conductor resistance is tested using a voltmeter, 1 ohmmeter, or a Wheatstone bridge