How to install three-phase ammeter

Connection mode of single-phase watt-hour meter:

(1) Connection mode of single-phase AC watt-hour meter. The measurement of AC electric energy mostly adopts inductive watt-hour meter. The single-phase watt-hour meter has a special junction box. There are four end buttons in the junction box. When the instrument leaves the factory, the voltage and current coils have been connected in the junction box. The single-phase watt-hour meter * * has four terminals numbered 1, 2, 3 and 4 from left to right. When wiring, just press L and 3 to terminate the power supply and press 2 and 4 to terminate the load. If the load current or voltage is high, it should be connected to the circuit through a current or voltage transformer.

Connection mode of three-phase watt-hour meter:

The three-phase watt-hour meter is composed of two single-phase watt-hour meters according to the principle of measuring power by two meters. The connection mode of three-phase watt-hour meter is slightly different according to the difference of three-phase power line system.

For direct three-phase four-wire watt-hour meter, there are 1 1 terminals from left to right, 1, 4 and 7 are three-phase incoming lines of A, B and C, 10 is neutral incoming line, 3, 6 and 9 are three-phase outgoing lines, and 65438+.

For heavy load circuits, indirect three-phase watt-hour meters must be used, and the wiring needs 2 ~ 3 current transformers with the same specifications. Note that the current measurement sampling of each current transformer must be in phase with its voltage sampling, that is, 1, 2,3 is a group; 4, 5 and 6 are a group; 7, 8 and 9 are a group. ?

Second, the electric energy meter installation and use matters needing attention:

(1) The wiring of the electric energy meter is complicated. Before wiring, the voltage terminal and current terminal of the watt-hour meter must be distinguished, and then connected according to the technical specifications. For three watt-hour meters, pay attention to the phase sequence of the circuit.

(2) The accuracy of the watt-hour meter can only be guaranteed if it works under the conditions of rated voltage, rated current of 20% to 120 and rated frequency of 50 Hz.

(3) The watt-hour meter should not work when it is less than 5% of the specified current and 150% of the rated current.

(4) The watt-hour meter that has not been used for more than half a year should be recalibrated.

(5) When installing the watt-hour meter, it should be more than 0.5 meters away from the thermal system and 0.7~2.0 meters away from the ground, and the allowable deviation should not exceed 2 cm.

Three, low-voltage single-phase, three-phase watt-hour meter installation is completed, what are the contents of the inspection in the power failure state?

(1) Check whether the installed watt-hour meter, transformer and transformer are consistent with those listed in the work order, and check whether the word code of the watt-hour meter is correct.

(2) Check whether the wiring screws and bolts of the watt-hour meter and transformer are tightened, and whether the primary terminal washer and spring coil of transformer are missing.

(3) Check whether the electric energy meter and transformer are installed firmly and whether the inclination of the electric energy meter exceeds 1 ~ 2.

(4) Check whether the wiring of the electric energy meter is correct, and pay special attention to whether the polarity symbol corresponds to the phase of the voltage and current terminals.

(5) Check whether the magnification of the electric energy meter is correct.

(6) Check whether the voltage loop of the secondary conductor section is greater than 2.5mm2 and the current loop is greater than 4mm2. There should be no seams and construction scars in the middle. Whether the grounding is good.