It is easy to judge whether the heating tube is good or not with a multimeter, because it has only two states, short circuit and open circuit. Short circuit is rare, because the insurance will explode once it is used, and it is easy to burn and open. The open circuit is easy to measure. Use the ohm range of the multimeter. If it is connected, there is no disconnection, and if it is not connected, it will be broken. Knowing that the general measurement method is actually enough, please see below for more details.
Multimeter measuring electric heating tube method
The heating tube can be regarded as a pure resistive load, and the current flowing through the heating tube is pure active current. Use a clamp multimeter with AC current measurement function to measure the current when the heating tube is working. The value obtained by multiplying the current value by the rated voltage of the heating tube is the power (wattage) of the heating tube.
For example, the rated voltage of an electric heating tube is 220 volts, and the measured current is about 2 amps, so the power of this heating tube is about 440 watts. If the rated voltage of the heating tube is 380 volts and the measured current is about 1 ampere, then the power of the heating tube is about 400 watts.
There is a problem to pay attention to here, that is, the rated voltage of the heating tube. The heating tube with a rated voltage of 220 volts is connected to a voltage of 380 volts, and the heating wire will be burned quickly because of the high voltage. Conversely, if a heating tube with a rated voltage of 380 volts is connected to a voltage of 220 volts, the rated power will not be reached because the rated voltage is not reached.
How to measure the quality of electric heating tube with a multimeter
Measure that the electric heating tube is connected and has a small resistance value. It is good that the wire end is insulated from the outer metal body.
According to your parameters, the resistance of the heating tube should be about 5.4 ohms, which can be measured with the resistance X1 of a multimeter, but the resistance is generally divided into a cold state and a hot state, and the multiple of the difference is 10 times according to the material. Therefore, the test should not be based on 5.4 as the standard, as long as it is not 0 (short-circuit the test leads first, look at the displayed data, and measure the resistance value of the heating tube to subtract the data when the short-circuit is connected), or the resistance value is greater than 100 ohms. It can show that the heating tube is good, and vice versa.