Positive to Negative Ground Conversion Progress

The 120A generator, which will be installed pre-transmission, will be re-polarized in a hope to convert the bus to negative ground. It appears, through careful study of the dual field voltage regulator, that there are NO diodes or other current direction sensitive devices that require replacement of the regulator for negative ground operation. The starter for the engine, like most, is a field wound DC motor so reversing both the armature and the field windings results in same direction of rotation. Lighting systems, etc. do not care about which direction current flows. VDO instruments have been acquired to monitor the following:

  • Electronic Speedometer (0-85MPH)
  • Electric Engine Oil Pressure (0-80psi)
  • Electric Engine Coolant Temperature (0-250F)
  • Electric Transmission Oil Temperature (0-400F)
  • Electric Fuel Level
  • Electric Transmission Main Pressure (0-150psi)

The coach already has a gauge for showing charging/discharging and hopefully will continue to work (just with reversed what-is-what). The only loss to the whole project will be that I will sell my 12V +ground stewart warner fuel gauge that I got off ebay last year. All air pressure gauges are mechanical. A HUGE advantage will be that all negative ground device, like the stereo, CB, phone chargers, etc. no longer have to be ground isolated or use a converter. Also, my DSI water heater, which has a negative to ground bond that is very difficult to break and keep operating (the auto ignite sparker uses negative ground as a return path to the high voltage coil), will be able to be hooked up normally. All in all, a very reasonable setup for zero dollar cost (all gauges except engine oil temp were failed or had broken senders).

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