Expert summary on how to distinguish ABC three-pha

2022-08-09
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How to distinguish three phases of cables a, B and C? Power expert summary

represents each phase of ABC. It is specified in the three-phase system that B lags 120 degrees behind phase A and C lags 120 degrees behind phase B, so there is a problem of phase sequence. A. Use yellow, green and red 4 for phase B and C respectively It is indicated when the experimental machine is installed and changed for the first time. Due to the phase difference between different phases, there is also a voltage difference, which cannot be connected together. If three-phase electricity is introduced into office buildings and other places, but it is mainly single-phase electrical appliances, we should pay attention to it. Never connect two live wires casually, and we must ensure the same phase. As for whether the phase sequence is important or not, it depends on the specific electrical appliances. It doesn't matter if it's an electric heating device. If it's an electric motor, it's proved that it doesn't work. If the phase sequence is wrong, the rotation direction of the motor is the opposite

abc, BCA and cab have the same phase sequence, while CBA, ACB and BAC have the opposite phase sequence. The phase sequence can be measured with a phase sequencer, that is, assume that one is phase a, and then judge B and C

distinguish ABC phase with the color of conductor

all are live wires, the line voltage is 380V, and each wire pin is 220V for the zero wire

abc is used to distinguish the phase sequence of electric power. Generally, colors are used to distinguish the phase sequence in electric power. Generally, yellow lines (or yellow signs) represent phase a,

green represents phase B, and red represents phase C. This is to thoroughly implement the decision and deployment of the provincial Party committee and the provincial government on implementing the major projects of new and old kinetic energy conversion; The saying of live wire generally refers to the low voltage below 380V. The wiring of low voltage is generally three-phase four wire system (that is, three live wires (with points) and one zero wire (not electrified)) and three-phase five wire system (there is one more protective wire than three-phase four wires). Which method is adopted generally depends on the grounding and protection method. The main function of distinguishing phase sequence is to ensure the balance of load

use phase detector to detect ABC phase

phase detector phase detector can be divided into two categories: wireless phase detector and wired phase detector

I. phase detector

phase detector is applied to phase verification and phase sequence verification of power lines and substations, and has the functions of phase verification, phase sequence measurement, power verification, etc. It has strong anti-interference, meets the requirements of (EMC) standards, and is suitable for various electromagnetic interference occasions. The measured high voltage phase signal is taken out by the collector and directly transmitted after processing. It is received by the receiver and compared with the phase, and the results after the nuclear phase are qualitative. Because this product is wireless transmission, it is really safe, reliable, fast and accurate, and suitable for various nuclear phase occasions

main features:

screen display content: wireless phase detector, different phases, in-phase, x, y and their waveforms, phase angle

power supply: one battery of the host (neda-604/6f22) or equivalent model. X and Y collectors have 5 AG13 batteries

automatic shutdown: the host will shut down automatically about 15 minutes after startup

backlight: in the process of phase detection, if the light is too dark, making it difficult to read data, you can press the backlight switch

main technical indicators:

accuracy: self calibration error ≤ 2 ° field test: in-phase error ≤ 10 ° different phase error ≤ 15 °

sampling rate 3 times/s

host power supply is 9V ± 2V

power supply voltage of X and Y collectors is 7.5V ± 1.5V

host working current ≤ 7ma

working current of X and Y collectors ≤ 4mA

host and X The sight distance transmission distance of Y collector is x ≥ 80m y ≥ 50m

working environment: -35 ℃ -+45 ℃ humidity ≤ 95% RH

storage environment: -40 ℃ -+4. The power source (electromechanical) of the experimental machine is also called motor 55 ℃ humidity ≤ 95% RH

voltage level: 6 - 10kV, 35kV, 110KV, 220kV, 330kV, 500kV

Second, phase detector

phase detector, The phases of two power sources (generator sets) can be determined in 6, 10, 35, 110, 220, 330 and 500 kV systems respectively, so as to determine and. It has the characteristics of light weight (about 2-4kg), small volume and simple operation

main technical parameters:

ambient temperature: -10-40 ℃

ambient humidity: 20-80% RH

display mode: digital display of the measured voltage

power switch: automatic

220V low voltage can be used to check whether the nuclear phase instrument is normal

when the phases are different, the language "different phases" is sent out and the light is displayed

the simplest method: use an electric bulb to detect

the phase sequence found by the voltage transformer is relatively simple and easy to use. The high voltage is connected to one of the two groups of power supplies, then the load is connected to the bulb, and the in-phase lamp is off. In addition, the power supply bureau has a phase sequence discriminator similar to electroscope, but it is expensive to buy, so they can do it

one end of the cable is grounded, and the other end is connected to the ground with a multimeter. The connected phase is the same as the grounded phase (pointer multimeter we use). That's how we measured 10kV cable

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