Reverse Polarity Damage
This is the permanent damage that occurs in the electronics as a result of connecting the supply terminals with the positive and negative swapped. In the GS740-3P wire colour code, red is the supply positive and black is the supply negative and chassis. Reverse polarity protection is not declared in the product documentation; there is only a warning not to reverse the connection.
In a reverse connection the source of the damage is that elements which normally do not pass current in the reverse direction are forced directly into conduction. The result is usually instantaneous and permanent; even a brief contact can be enough. For this reason reverse polarity is not a mistake that can be made good by correcting it afterwards.
The habits that prevent the error during installation are these:
- Measure the supply terminals before connecting; even if the colour code is correct, the vehicle's wiring may have been modified.
- Connect the chassis terminal (black) to a solid, unpainted metal point.
- Apply power after the wiring is fully connected; do not try terminals on live wiring.
- After the battery has been removed and refitted, verify the polarity once more on first power-up.
If the system does not come on at all after a faulty connection, first check the fuse in the supply path and the terminal voltages; but proceed knowing that damage on the electronics side will not come back with a fuse change.
Context in which this term is used: Electronic speed and throttle control on diesel engines