Electric energy meters are used by almost every household. I believe that most electricians are very familiar with it. Even many non-electricians have learned about it. Under normal circumstances, electric energy meters have two most important current indicators: basic current Ib and rated maximum current Imax. In many cases, we generally only look at the energy readings when using the energy meter. Few masters pay special attention to these two currents. In fact, these two current indicators are important attributes of the energy meter. , And the accuracy, sensitivity and rated power of the electric energy meter have a great relationship.
We often use the 4 times meter in the home circuit, let’s look at a few examples: 5(20)A, 10(40)A, 15(60)A, 20(80)A This form of electric energy meter is called It is a 4 times meter, and of course there are 2 times meter, 5 times meter and 6 times meter, but it is not widely used in home circuits. Generally, the higher the multiple of the electric energy meter, the more accurate the measurement at low current.
There are also multiple levels of electric energy meters. Generally, two-level meters are used in home circuits. Different levels of electric energy meters have different starting currents and naturally different sensitivity.
The first thing to know is that the basic current is the current value that reflects the relevant characteristics of the electric energy meter, and it is also called the nominal current value. It is determined by the starting current of the electric energy meter and is related to the sensitivity of the electric energy meter.
For a 2.0-level electric energy meter, the starting current is about 0.5% of the basic current (Ib).
The rated maximum current of the electric energy meter refers to the maximum current that can meet the accuracy of the electric energy meter, and is related to the total power and total load of the household circuit. When calculating the maximum power of electrical appliances allowed in the circuit, we use the maximum rated current (Imax) of the electric energy meter. If it is used over the range, under normal circumstances, the electric energy meter will not be burned out, but it will affect the measurement accuracy of the electric energy meter, and the measurement result will be inaccurate or even fast.
The basic current of the electric energy meter is related to the starting current. For a family 2.0 electric energy meter, the starting current is about 0.5% of the basic current (Ib). Let's compare the two current indicators.
Take 5(20)A and 10(20)A as examples:
The starting current of a 5(20)A electric energy meter is about 0.025A.
The starting current of a 10(20)A electric energy meter is about 0.05A.
It can be clearly seen that the starting current of 5 (20) A will be smaller, and the corresponding sensitivity will be higher. This is what we are talking about: In general, the higher the multiple of the electric energy meter, the higher the sensitivity and the more accurate.
The difference between the basic current and the rated maximum current of an electric energy meter. Mastering these two currents is also the most basic skill for electricians to get started, regarding the basic attributes of electric energy meters.