According to the analysis of the control circuit of the diesel generator set and the electromagnetic compatibility design experience, the solutions to the LED interference problem of the AC power output indicator of the diesel generator set are:
1.Use anti-interference LED indicator with high trigger voltage
Aiming at the problem of incorrect indication of the AC output indicator of diesel generator sets, many manufacturers of power generation equipment believe that the use of indicators with high anti-interference ability of high trigger voltage can solve this problem. The internal circuit of this kind of indicator light has been improved. It has an additional threshold circuit than the ordinary indicator light, which increases the threshold voltage of the LED, so that the threshold voltage of the LED is increased from the principle of 3.6V to 30V. Interference problem of AC output indicator of diesel generator set.
2.Resistance in series on the indicator
A resistor in series with the AC power output indicator to divide the voltage can effectively reduce the induced voltage of the indicator LED. However, if the resistance is larger, the divided voltage obtained by the resistance will be larger, and the current through the resistance will be smaller. If the resistance is too large, it will affect the normal lighting of the AC power output indicator. Therefore, when solving practical problems, you should Select a suitable resistor according to the actual induced voltage of the AC power output indicator.
3. Line isolation
Adjust the control principle of the diesel generator set, using the auxiliary contact of the output contactor or the normally open contact of the intermediate relay that is closed synchronously with the output switch, to isolate the interfering component circuits and reduce the mutual coupling and induction between components. .
The shielded wire is used for the conductor, the shielded cable is used for the cable, and the single-core shielded and double-jacketed shielded cable is used for the multi-core cable. The shielding layer of the shielded cable should be effectively and reliably grounded to avoid induced voltage on the cable.
Reliable and reasonable grounding can eliminate the interference source caused by the ground potential difference caused by the leakage current of the power filter to the ground capacitance.