The Skill of Distinguishing True from False Power Amplifier

1. Judging from the printed fonts: the genuine fonts are symmetrical and beautiful, and the handwriting is not easy to be wiped off, while the fake fonts are just like the ones written on them. Gently scraping with your fingernails will make the handwriting color lighter, or even the paint can not be seen clearly.

2. From the perspective of packaging press marks: English letters and numbers are printed on both sides of the solid screw hole near the upper part of the pipe, and the words of packaging from different manufacturers or countries are printed on the middle of the lower part near the pin, such as SK (Sanken), PHILIPPINES (Philippines), MALAYSIA (Malaysia), etc. Fake products have no printing, or the printing on the top two points is too bloated and ugly, while the printing on the bottom one is simply not printed because of the number of characters. Of course, some joint venture pipes have no printing here, but there is no obvious difference from the original pipes in other aspects.

3. From the perspective of the packaging and processing technology of the power amplifier tube, the boundary of the bonding point between the genuine heat sink and the packaging plastic is clear and the corners are flat, while the boundary of the bonding point of the counterfeit is not clear and even has gaps (the most common counterfeit products in the market are the small Toshiba tube A1491/C5198, D817/D1047), and the surface is rough as if it has been brushed (this is the place where the counterfeit products are most likely to be exposed). The radiator surface of some models of imported pipes has been treated by sanding process (such as MJL1302A/MJL3281A of MATALOLA), while the counterfeit and individual joint venture pipes do not have this process.

4. From the measurement results: use the pointer multimeter R × When 10k is used to block the measurement of the forward and reverse resistance between the c and e poles of the pipe, the pointer of the authentic product is stationary at ∞ or the angle of swing is very small, while the swing angle of the forward resistance of the c and e poles of the counterfeit product (the NPN forward direction is Rce, the PNP forward direction is Rec) is much larger, that is, the resistance value is small (this indicates that the pipe penetration current is large); And use a digital multimeter to measure the magnification of the pipe β The consistency of genuine products (especially inlet pipes) is very good, while the consistency of counterfeit products is generally poor.

5. The performance of fake products during installation and use: because the pressure resistance of pipes is generally low, it is very easy to cause the pipes to burn when starting up; Or the heating is more serious than that of the genuine product. At this time, the resistance of the c and e poles of the pipe is much smaller than that of the pipe when it is not installed β The deviation of is greater, and the authentic products do not have this phenomenon.

1. Control processor error failure

Fault cause: The control chip of the main control board (mainly the AD sampling chip) is disturbed.

Handling method: If there are two or more records, replace the drive, and try to replace the drive.

2. Overspeed error fault

Cause of failure: 1) Driver AD sampling failure; 2) Other faults.

Handling method: Read the fault record, and focus on what is the next fault record of overspeed error. If the operation time of two faults is similar, the next fault record of overspeed error shall be taken as the basis for handling. Otherwise, the fault may not be caused by the driver, and it can be reset and then operated for observation.

3. Intermediate circuit overvoltage fault

Fault causes: 1) Brake resistance is bad; 2) Frequent braking in windy weather.

Treatment method: first confirm whether the brake resistor is damaged. If the brake resistor is damaged, replace the driver.

4. Failure cannot be reset

Fault cause: the reset optocoupler of the driver main control board is damaged.

Handling method: power off reset is available, and the fault is displayed as the basis for handling.

5. Low voltage power supply error fault

Fault causes: 1) The low-voltage power supply of the driver is abnormal; 2) AD sampling chip is disturbed; 3) The driver will report the 24V instantaneous power failure.

Handling method: If there are many wrong fault records of low-voltage power supply (more than 3 times), or there are RF fault records at the same time, change the driver.

6. Output short circuit fault

Cause of fault: The driver detects that the output current is high.

Handling method: check whether the motor has problems. If the motor has no problems and there are two or more IK failures and shutdowns, replace the driver.

7. Ground error fault

Fault cause: three-phase 400V input is unbalanced or there is electric leakage.

Treatment method: check whether the grounding wire is in good condition and whether the motor has problems. If there is no problem and there are two or more times of shutdown due to grounding error, replace the drive.

1. Symptom: All copper sheets are blackened

Possible cause: motor overload, motor undervoltage operation

Handling method: lighten the load or replace the enlarged motor; Check the battery or controller

2. Fault phenomenon: the reversing blades are blackened in groups in a certain order

Possible cause: short circuit between commutating plates or armature coil; Poor welding or short circuit between the reversing plate and the armature coil.

Treatment method: replace the rotor; Rotor repair

3. Fault phenomenon: the reversing plate is blackened, but there is no certain rule

Possible causes: the centerline of the commutator plate is displaced or the commutator surface is not round

Treatment method: adjust brush holder or process commutator surface

4. Fault phenomenon: the brush is worn, discolored and cracked

Possible causes: the brush is worn, discolored and cracked; Motor vibration; The clearance between the brush and the brush box is too large, and the distance between the brush box and the working surface of the commutator is too large; The mica between sheets on the commutator is prominent; The brush material is poor.

Treatment method: adjust the motor connection and fixed parts; Replace the brush holder or brush; Re engrave the commutator mica; Replace the brush.

5. Fault phenomenon: large spark

Possible cause: the commutator is not clean; The commutator is not smooth and round; The mica sheet or part of the reversing sheet protrudes; Poor brush grinding; Insufficient brush pressure; Wrong brush brand; The electric brush is stuck in the brush box; The brush holder is loose or vibrates; The center line of electric brush and magnetic pole is not aligned; The polarity and arrangement of magnetic poles are not correct.

Processing method: processing chin commutator; It is required to reduce the voltage, run in the brush with no load or light load until the contact surface reaches more than 80%; Repair or replace the brush or brush holder Adjust the brush box or brush holder to align the brush with the center line of the magnetic pole; Replace the motor.

6. Fault phenomenon: the brush and brush braid are hot

Possible causes: motor overload; The motor operates under voltage; The contact between the brush and the flexible wire is poor, and the sectional area of the flexible wire is too small.

Processing mode: lighten the load; Check the battery or controller; Replace the brush.

7. Fault phenomenon: the brush is noisy.

Possible cause: The commutator surface is not smooth.

Processing method: reprocess the commutator.

8. Fault phenomenon: the motor is seriously heated

Possible causes: motor overload; The motor operates under voltage; The connecting wire between the motor and the controller is too thin or damaged.

Handling method: lighten the load or replace the enlarged motor; Check the battery or controller; Replace the connecting wire.

9. Fault phenomenon: motor noise is abnormal.

Possible causes: bearing damage; The motor is damaged during transportation; Coaxial connection between motor and vehicle is too large; The input shaft of the vehicle gearbox has large runout.

Treatment method: replace the bearing; Replace the broken parts; Adjust the connection between motor and vehicle; Adjust the gearbox.

10. Fault phenomenon: the motor does not work.

Possible cause: power supply is not available; Wiring error; Motor internal fault (short circuit or open circuit).

Treatment method: check the battery or controller and connect the power supply; Wiring according to correct requirements; The professional department shall repair or replace the motor.