External shunt

Attached externallyshuntFL-2shuntDefinition:

External shuntIn fact, it is a resistor with a very small resistance value. When a direct current passes through it, it generates a voltage drop for display on the direct current meter;

The DC ammeter is actually a voltmeter with a full scale value of 75mV;

DC ammeter andshuntIt is used in conjunction with others;

For example, a 100A ammeter paired with itshuntThe resistance value is 0.00075 ohms;

That is, 100A * 0.00075 ohms=75mV;

50A ammeter matchingshuntThe resistance value is 0.0015 ohms;

50A*0.0015 欧=75mV。

2、 Measurement:

How to measure a large direct current, such as tens of amperes, or even larger, hundreds of amperes, without a large range ammeter for current measurement? This needs to be adoptedshunt.shuntIt is a resistor that can withstand high currents when current flows through itshuntAt this point, a millivolt level voltage will appear at both ends, so a millivolt voltmeter is used to measure this voltage and convert it into current The measurement of high current has been completed.

There are various specifications of ammeters, but the actual meter head is a standard millivolt voltmeter. For example, a voltmeter with a full scale of 75mV. So to measure a current of, for example, 20A with this voltmeter, it is necessary to equip it with a shunt resistor that produces a 75mV voltage drop when a current of 20A flows through it, also known as 75mVshunt.

　　shuntIt is a resistor that can pass a very large current, and commonly used ammeters with 1, 20A, and 3 require itshunt，shuntThe impedance of the meter is equal to the full voltage of the meter mark divided by the full current of the meter. For example, a 20A ammetershuntThe resistance value is 75mv * 10-3/2A=0.00375 Ω. After the impedance is constant, according to Ohm's law U=IR, the current is proportional to the voltage. The current is linear and the voltage is also linear. Therefore, a voltmeter with a full scale of 75mv can be used to display the current. Therefore, the ammeter used is actually a voltmeter.

How to measure high current in communication? By using a current transformer, a large current can be converted into a small current of less than 5 amperes at a certain transformation ratio. Therefore, a small range AC ammeter can be used to measure large currents, but the measured current needs to be multiplied by that transformation ratio.

It is a short conductor that can be made of various metals or alloys and also connected to terminals; Its DC resistance is strictly adjusted; Connected in series in a DC circuit, the DC current passes throughshunt，shuntGenerate millivolt level DC voltage signals at both ends and connect them in parallelshuntThe pointer of the meter at both ends swings, and the reading is the current value in the DC circuit. The so-called shunt refers to dividing a small current to drive the meter reading. The smaller the ratio of this small current (mA) to the current in the large circuit (1A - tens of A), the better and more linear the ammeter reading will be. This is a commonly used product in electrical circuits, with lightning protection and shunt measures.

Three,shuntSelection description:

FL-2 series 250A/75mV and 300A/75mVshuntIt is mainly composed of manganese copper sheet (Cu Mn) and copper joint weldingshuntThere are two sets of terminal knobs on the two ends of the joint: the outer set is a potential terminal knob for connecting to the power line, and the inner set is a potential terminal knob for connecting to the measuring instrument. Our company specializes in producing various fixed fixed fixed valuesshuntWe can customize special styles (including export types) for customers based on the electrical parameters and dimensions of precision alloy resistorsshuntIf there are special requirements, customized orders can be placed. Above 150A/75mVshuntIf additional base isolation is still required, our company usually uses high temperature resistant materials (DuPont: HTNFR52G15BL, melting point: 310 degrees fireproof V0 injection grade)

FL-2 seriesshuntIts accuracy is 0.5 level, with specifications ranging from 1A to 15000A. The secondary voltage is 20mV, 30mV, 50mV, 60mV, 75mV, 100mV, 150mV, etc. The conventional one is 75mV. Usually, FL-29 or FL-39 outer diameter sizes are improved for 2000A and above.

One Product UsageshuntWidely used to expand the current measurement range of instruments and can be applied to communication systems

The power supply and other circuits of electronic whole machine automation control are limited in current Uniform flow Sampling Detection function, using condition B

Group.

II Main technical parameters:

1. Accuracy level: 5~4000A: Level 0.5, 5000A~10000A: Level 1.

2. Environmental conditions for use: -40~+60 ℃, relative humidity ≤ 95% (35 ℃)

3. Mechanical resistance: able to withstand acceleration of 70 meters per second and impact frequency per minute

80-120 times of 6-hour transportation shaking.

4. Overload performance: rated current 120%, 2 hours.

5. Voltage drop: 50mV, 75mV, 100mV, 200mV, 300mV

6. Heating under load: The temperature rise tends to stabilize and the current below 50A does not exceed 80 ℃. Rated current above 50A shall not exceed 120 ℃.

IIIshuntModel representation rules:

FL-2 200A 75mV 0.5％

(Model) (Current) (Voltage Drop) (Accuracy)

4shuntPrinciple and wiring method