Positive ground. 7

[itsmoked]

Got a positive ground on an instrumented rail car. The car was designed to do coupling based tension measurements, (think how many tons of pull are there between 7 locomotives and the 125 coal hoppers behind).

The car has racks and racks of ancient electrical measurement stuff in it. Looks like those panels in front of the phone operators of old.

Besides all this instrumentation there are house lights, dual 3-71 diesel generators, blowers, battery charger, air conditioning and some controls.

Well like I say, the dang car is wired with a positive ground!!

All the instrumentation is going to be yanked and the car is going to be converted into an escort car for things like Space Shuttle Booster motor sections.

Questions:
1) Why would someone have made this car positive ground?

2) What would be stumbling blocks to converting it to negative ground?


Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[DaveScott]

For interest, Japan generally uses positive grounded 24V dc for control systems.
Mitsubishi PLC systems are available in Japan and Europe, but in Europe, they are negative ground...
Some systems are not earthed, and have capacitive coupling from both + and - to ground.
Try working on a plant that has all three systems...

 

[itsmoked]

DaveScott; I think I'd just shoot myself...

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[DaveScott]

I tried, but the European bullet didn't fit into the Japanese gun.

 

[itsmoked]

BJC; I made a call and put the right two people together.

Tiz outta my hands now.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[BJC]

Didn't mean to cause you any trouble. I am not into trains but have a friend that is. He has also told me that there quite a few private rail cars out there. Some are very plush. It turns out a lot of them don't meet Amtrak standards ( what ever they are). The railroads don't make it cheap to put one on a train. The bathroom on trains used to be a hole that opened down to the track. You can't do that any more.
Hopefully someone will trade the guy a car like the one in the "Wild. Wild West" movie. That on I belive had a pool table in it, playing pool in a moving train has to be different.

 

[ScottyUK]

Outright impossible on a British train. It would be similar to that current HP advertisement with the millions of coloured balls going down the street! On the French TGV it is a distinct possibility, as with the Swiss railways.


----------------------------------

I don't suffer from insanity. I enjoy it...

 

[itsmoked]

These cars often operate in freight service.. You would be considered a full on idiot to be standing up in freight service unless it was really necessary! People have been launched. One poor sole was ejected out of the shower onto the toilet. Broken arm and all.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com