1 fuse tube blown
Fuse fuse fuses The internal circuit of the electric car charger has a short circuit or overcurrent fault. This is due to the charger for a long time working in high voltage, high current state, the internal device due to the higher failure rate. In addition, the grid voltage fluctuations, surges will cause the charger to instantaneous increase in the current fuse fuse.
2 DC voltage output is too high
This fault is often caused by the steady-state sampling and regulator control circuit, in the electric car charger, the DC output, sampling resistor, error sampling amplifier, optical coupler, power control chip together constitute a closed control Loop, any problem will lead to voltage rise.
3 DC voltage output is too low
According to maintenance experience, in addition to the regulator circuit will cause the output voltage is too low, there are the following reasons:
(1) output voltage side rectifier three pole Ju, filter capacitor failure, you can judge through the substitution method.
(2) the performance of the switching power tube, resulting in the switch can not be properly turned on, so that the power of the internal resistance increases, with load capacity decreased.
(3) The source of the switching power tube is usually connected with a resistor with a small but very high power resistance, as a resistance for overcurrent detection. The resistance of the resistance - as in 0.2 ~ O.8Ω. If the resistance variable or open welding, poor contact can also cause the output voltage is too low.
(4) high-frequency pulse transformer bad, not only cause the output strider pressure drop, but also cause switching power tube excitation and thus repeated loss of switch tube.
(5) high-voltage DC filter capacitor is poor, resulting in poor power supply with load capacity.
(6) power supply line bad contact, there is a set of contact resistance, resulting in output voltage is too low.