How to select a multi-user energy meter for current transformer 150/5 is the ratio of the current transformer. The current transformer proportionally changes the large ammeter to a small current. For example, 150/5 is to reduce the large current by a ratio of 1/30. The purpose is twofold: one is to reduce the cost of multi-user energy meters for metering equipment; the other is to standardize multi-user energy meters, and the input current of multi-user energy meters is only 1A or 5A, which is specifically 1A or 5A It depends on the ratio of the current transformer you choose. For example, if you choose 150/5, choose a 5A watt-hour meter, choose 150/1 current transformer, and choose 1A.
When reading the multi-user energy meter, it needs to be multiplied by the transformation ratio just before. Before the pre-paid meter leaves the factory, we will perform a series of performance tests. Among them, the withstand voltage test is an important one. Today we will understand the method of the multi-user energy meter withstand voltage test:
1.Environmental conditions: Under the conditions of room temperature and air relative humidity not more than 80%
2. The auxiliary circuit whose reference voltage is not greater than 40V is grounded during the test.
3. Add one end of the 2KV test voltage to all connected voltage terminals, current terminals and all auxiliary terminals with a reference voltage greater than 40V, and the other end to the metal part accessible from the outside of the energy meter and the ground of the case. End button (if the meter case is insulated, add it to the conductive plate on which the case is placed).
4. The test voltage shall be increased from zero to the specified value in a balanced manner within (5-10) s and held for 1 min, and then reduced to zero at the same speed.
5. The test result is that the insulation should not be broken down, and the energy meter should be able to work normally after the test.
6. The watt-hour meter that passed the voltage test is transferred to the primary school.
7. The unqualified electric energy meter states the failure phenomenon, fills in the "Disqualified Product Disposal Form", puts it in the to-be-operated turnover box and transfers it to the return station.