Dumb Question on Wiring Diagrams MEP 803a

[Shaky_Jake]

I am familiar with ladder diagrams and wiring schematics in my line of work (HVAC service tech) with AC circuits. I am not to familiar with DC diagrams . Two questions: The upside down triangles with a letter in it for example "V", "N" and such, do those represent pins in the diagnostic port on the outside of the genset? I am also wondering what all the diodes are used for in the circuits? Are they used sort of like check valves or do they have other uses?

 

[Guyfang]

I am familiar with ladder diagrams and wiring schematics in my line of work (HVAC service tech) with AC circuits. I am not to familiar with DC diagrams . Two questions: The upside down triangles with a letter in it for example "V", "N" and such, do those represent pins in the diagnostic port on the outside of the genset? (Yes they do) I am also wondering what all the diodes are used for in the circuits? Are they used sort of like check valves (More or less) or do they have other uses?

@kloppk ?

 

[DieselAddict]

They represent which pin on the diagnostic port that spot is connected to. For me it’s an under appreciated feature. I can probe many useful points for troubleshooting without opening up the set.

 

[kloppk]

Correct, the diodes operate like check valves by only allowing current to flow in one direction thru them. For instance CR1 is there to protect the DC portion if the genset from being damaged should the batteries get hooked up backwards. Some of the other diodes are there to supress current spikes induced when large relay or solenoid coils are de-energized such as CR5 on the Fuel Shutoff solenoid curcuit.