struktūra ir darbo principas rodyklė tipas spaustukas rodyklė metras
Clamp ampmeters can generally be divided into two categories: magnetoelectric and electromagnetic. Among them, the one that measures power frequency alternating current is the magnetoelectric type, while the electromagnetic type is both AC and DC. This article most introduces the measurement principle and use method of magnetoelectric clamp ampmeter.
1. Magnetinis spaustukas ampermetras konstrukcija
T magnetoelektrinis spaustukas ampermetras is daugiausia komponuota of a speciali srovė transformatorius, a lygintuvas magnetoelektrinis ampermetras ir vidinės grandinės. Paprastai bendri modeliai are: T301 tipas ir T302 tipas. T301 tipas spaustukas ampermetras can only matas AC current, while the T302 type can measure abu AC current and AC voltage. There are also pocket clamp ampmeters for AC and DC, such MG20, MG26, MG36 and other models.
2. Darbinis principas spaustukas ampermetras
The working principle of the clamp ampmeter is based on the working principle of the current transformer. When the clamp ampmeter wrench is held sandariai, the core of the current transformer can be open, and the wire of the measured current enters the inside of the jaw as a current mutual inductance. primary winding of the device. Kai geležis šerdis of the loosening veržliaraktis is uždarytas, an indukuotas current is generuotas on its antrinis apvija pagal to the principle of the transformer, and the ampmeter pointer deflekcts, thereby indicating the value of the measured current.
Ix=Ia/N
In the formula, Ia is the reading on the ampmeter; N is the number of winding turns.
3. Kaip naudoti naudoti spaustukas ampermetras
(1) Select the clamp ampmeter correct according to the type and voltage level of the current being measured. Generally, for lines with AC voltage below 500 V, type T301 is used. When measurement the current of a high-voltage line, a high-voltage clamp ampmeter that matchs its voltage level should be used.
(2) Teisingai patikrinkite ar the appearance of the clamp ampmeter, the closing condition of the jaws and the condition of the meter head are normal. If the pointer is not at zero, mechanical zero adjustment should be performed.
(3) Select the appropriate range of the clamp-type ampmeter render to the size of the measured current. The selected range should be little larger than the measured current value. If the magnitude of the current being measured is not known, the maximum range should be used for estimation first.
(4) Matas teisingai. Kada matavimas, presas the veržliaraktis sandariai atidaryti the jaws. Vieta the wire under test into the center of the jaws, loosen the wrench and close the jaws sandariai.
(5) After reading, open the jaws, cancel the wire under test, and set the gear to the highest current level or OFF gear.
Measurement example: Measure the operating current of a cage-type asynchronous motor during operation. According to the current size, you can check and judge whether the motor is working normally to ensure the safe operation of the motor and extend its service life. First, correctly select the voltage level of the clamp-type ammeter, check whether its insulation is good, whether it is damaged, whether the pointer swings flexibly, and whether the jaws are rusted, etc. Estimate the rated current based on the motor power to select the range of the meter. When measuring, you can measure once for each phase or once for three phases. At this time, the number on the meter should be zero (because the sum of the three-phase current phasors is zero). When there are two phase wires in the clamp, the meter will display The value is the current value of the third phase. By measuring the current of each phase, it can be judged whether the motor is overloaded (the measured current exceeds the rated current value). The power supply voltage inside the motor or (a device that converts other forms of energy into electrical energy is called a power supply) Is there any problem, that is, whether the three-phase current imbalance exceeds the 10% limit.
