1, single-phase power socket wiring regulations
There are many kinds of single-phase sockets, often divided into two holes and three holes。
Two holes side by side, three holes to form a shape。
Next to the wiring hole, L is fire and N is zero。
There's an E in the three holes, which means the ground is in the middle。
Face the socket direction, each hole wiring has regulations。
Connect the neutral wire on the left and the fire on the right, and the PGND cable is connected to the middle。
2, the selection of leakage protector
Select leakage protector, power supply mode is the first。
Single phase power supply two hundred and two, two or single stage。
Three phase three line 380, choose three levels of protection。
Three phases, four wires, 380, four wires, three or four。
"Level" indicates the switch contact and "line" indicates the incoming and outgoing wires
3. Find the reason why the light bulb is not bright
The light bulb does not light is annoying, the common reason is that the filament breaks。
Transparent light bulb can see, otherwise it can be tested by electric pen。
Close both ends of the switch point, and the fire line is not bright。
A light off the filament is broken, both ends are lit off the zero line。
4, buried wire before buried core inspection and breakpoint determination method
Before the buried wire is buried, there is no broken core disk inspection。
Check the use of megohm meter, L end connected to the wire,
Put the other end of the wire into the water, do this at the E end of the meter,
Slowly shake the megohm meter, the needle less than zero is broken。
To find out where the breakpoint is, using instrument DG3,
Single-phase AC connected to one end, the instrument attached to the buried wire,
Moving slowly from beginning to end, the light still shining,
If the instrument light goes out, this is the break point。
5, low voltage test pen to judge the AC single-phase circuit fault method
Ac test pen, light for the fire line is not bright。
Circuit fault can be checked, power measurement fire and ground。
On off Normal check device, circuit disconnection is not suspicious。
If both ends are not bright, the power firewire has been disconnected。
If both ends light up, the zero line is broken or separated。
6, the method of measuring DC voltage with pointer type multimeter
Zero before measurement, range selection should be moderate。
Determine the positive and negative electrodes of the circuit, and clarify the parallel connection。
Black pen to the negative, red pen to the positive。
If the hand is reversed, the connection is positive and negative reverse polarity。
7. Method of measuring DC current with pointer type multimeter
Zero before measurement, range selection should be moderate。
Determine the positive and negative electrodes of the circuit, and clarify the series connection。
Black pen to the negative, red pen to the positive。
If the hand is reversed, the connection is positive and negative reverse polarity。
8. Method of measuring conductor DC resistance with pointer type multimeter
Measuring resistance select range, select range and then zero。
Two pen short circuit watch hand, not in the zero position to adjust。
Turn the ohm zero knob until the hand reaches zero。
Knob in the end is still several, replace the battery and adjust。
The contact must be good, and the hands should be suspended。
The measurement value is accurate, and the watch hand is best in the grid。
After measuring, turn off the power and turn the knob to the voltage。
9, use the pointer type multimeter to judge the quality of the capacitor
Capacitors are judged coarse, universal meters can bear。
Use resistance multiplied by K, and the pen is connected to one extreme。
The watch hands swing close to zero, then slowly back。
Reach a place to stop, the more back the healthier。
There is a short circuit to zero, and less leakage is returned。
The meter does not go at the beginning, and the internal line of the capacitor is broken。
10, with charge, discharge method to judge the quality of the capacitor
Capacitor is good or bad rough judgment, charge and discharge method can bear。
The capacitor is connected to DC at both ends and is cut off for a little time。
The conductor is connected to two poles, pay attention to whether there is any spark,
Fire is good without fire, and the same kind of fire is fuller。
11, "the rated capacity and voltage of the three-phase asynchronous motor are known, and the approximate value of the rated current is obtained.
Small and medium capacity high and low voltage, current estimation to see kilowatts。
The relationship is given as the median, with large volume reduction and small volume addition。
One kilowatt two amps, commonly used low 380。
High voltage motor three thousand volts, four kilowatts one amp current。
Six thousand volts higher, eight kilowatts an amp。
Rated voltage to 10,000, 13 kilowatts for one amp。
12, "Three-phase 380V motor switch to single-phase 220V power supply wiring method and capacitor capacity calculation
Motor three-phase to single-phase, winding connection according to the original。
All three outlet lines are useful, two power and one capacitance。
After connecting the capacitor, connect the power supply, connect the zero fire and turn the reverse。
Motor three-phase to single-phase, and connected to the capacity of capacitance。
Working capacitance connection method, star connection small to Angle to big。
The micro-weight of the hundred watt motor, the Angle connection is ten stars and six。
Starting capacitance can be as large as ten watts by two to three micromethods。
Capacitor voltage to see the power supply, two hundred and two power supply three hundred and three。
13. Phase relationship of current and voltage in inductive load circuit
Inductive wonderful in a "sense" word, feelings to come and go take time。
Just a meeting is very strange, the words in my heart are difficult to speak。
Once you need to break up, "lotus roots" also love。
Power supply a voltage, the current is difficult to access。
Cut off The power supply voltage is off, the current is difficult to cut off。
The above metaphor teaches popular, the voltage in the front flow behind。
The difference between the two electrical Angle, the maximum value of 90 degrees。
14. Weight estimation per kilometer of wire
The weight of the kilometer wire depends on the section and variety,
Section unit millimeter square, multiplied by the coefficient value is different。
Duralumin is the lightest two point eight, pure aluminum is followed by three times。
Steel core aluminum twisted times four, 7:08 iron is heavier。
Then the weight of pure copper eight eight, the heaviest steel nine zero。
Consider the sag and the lashing, and multiply that by one and a half。
Related formula: Mass = density X volume
Volume = base area X height
15, generator principle and right hand rule
The wire cuts the magnetic force lines and induces the electromagnetic force inside。
The wire is connected to a closed circuit, and there is current flowing through it。
Judge the direction of flow with your right hand, extending it flat。
The wire moves the thumb towards the center of the hand facing N extremes。
The direction of the four fingers is the current, and this end is also the positive extreme。
16. Kirchhoff's first Law and Second Law
Kirchhoff is famous. He invented the law of the circuit。
The node current is the first, and the outflow and inflow phases are equal。
The loop voltage is second, and the voltage drop and potential are equal。
17, "The relationship between the output DC voltage and the input AC voltage of the rectifier power supply and the reverse voltage of the rectifier diode.
Ac voltage to DC, how to find the output voltage？
Input voltage is 100, single phase half wave is four to five。
Three phase half wave 117, half wave twice full wave number。
If thyristor is used, start from zero to top。
Pipe back pressure to remember, single phase three phase different number。
Single-phase bridge type 141, three-phase bridge type 239。
Note: Input voltage should be phase voltage。
18. Calculation of total resistance value after series and parallel resistance
As the series value of resistance increases, the longer the series, the greater the resistance。
The parallel value of resistance decreases and the equivalent cross section increases。
The total resistance in parallel is difficult to calculate, and each value is required to be reciprocal first。
The reciprocal of the sum of the reciprocal is the parallel resistance。
There are only two resistors in parallel, and the total resistance can be simplified。
The product of the two resistors is the numerator, and the sum of the two resistors is the denominator。
19, "Three phase AC power supply of two connections and two ways of wire.
There are two kinds of three-phase connection, a triangle and a star。
Angular three phase around a circle, three vertex three phase line。
Stars are joined by three tails at a point called a neutral point。
The three leads to the three phase line, and the middle point leads to the neutral line。
The phase line is commonly called the fire line, and the middle line is commonly called the zero line。
The star connection can produce two kinds of wires, three phase three wire and four wire。
Three-phase three-wire has no zero line, three-phase four-wire has zero line。
20. Determination method of positive and negative electrode of rectifier diode
A diode has two poles, an anode and a cathode。
Distinguish polarity is simpler, first can look at the chart。
One end of the triangle is extremely negative, and one end of the short bar is anode。
There is no chart to see the shape, the rounder end is the anode。
Larger specifications with screws, one end of the screw is the anode。
If you do not trust the meter, all meters are ready。
Multiply by 100 resistance levels, connect the electrodes separately。
Positive and negative twice than the resistance value, a big and a small note carefully。
When the resistance value is small, watch the pen, red Yang black Yin fixed electrode。
21, "Bridge rectifier circuit connection method and resistance and capacitance protection, rectifier diode problems
Single-phase bridge type four tubes, two in series and then parallel。
Parallel two ends of the DC, the two tubes are connected to the power supply。
Three phase bridge six tubes, two in series and then parallel。
Parallel two ends of the DC, the two tubes are connected to the power supply。
Resistance-capacitance protection diode, you can choose from three connections。
One parallel on the AC side and one parallel on the DC side。
There is also a more complex and at both ends of each tube。
Inductive load back potential, parallel continuous diode。
22, magnets and the properties of magnets, magnetic fields and magnetic lines of force
Regardless of size or thickness, a magnet has two poles。
South Pole S and North Pole N, maximum magnetic force at either end。
Same poles repel and different poles attract. Everything is the same。
Description Magnetic field Lines of magnetic force, each of which is a closed line。
From N to S pole in vitro, and from S to N in vivo。
The lines do not cross each other and are relatively dense at both ends。
23. Filter circuit for reducing output current ripple
To obtain steady flow, the filter circuit is connected to the output。
One capacitor and one resistor, connected into a T-shaped path。
Two capacitors a reactance, the name is called the pie circuit。
There is also a simpler, two capacitors and a resistor。
24, the impact of brush deviation from the neutral line and adjustment methods
The excitation is switched on and off again, while looking at the instrument。
The pointer of the instrument swings back and forth, and the swing amplitude is larger and the brush is biased。
Gently rotate the brush holder to minimize the swing adjustment。
Electric motor positive and negative rotation, two speed to subtract。
If the difference is large, it indicates that the brush is relatively biased。
Gently rotate the brush holder, the difference is minimal adjustment
24, the impact of brush deviation from the neutral line and adjustment methods
The excitation is switched on and off again, while looking at the instrument。
The pointer of the instrument swings back and forth, and the swing amplitude is larger and the brush is biased。
Gently rotate the brush holder to minimize the swing adjustment。
Electric motor positive and negative rotation, two speed to subtract。
If the difference is large, it indicates that the brush is relatively biased。
Gently rotate the brush holder, the difference is minimal adjustment。
More information please pay attention to Baoding Kone Electrical Equipment Co., LTD
