Engine Electric's

[Anonymous]

I have some questions on Diesel Locomotive's. I do not work for the railroad so some of these question might seem pretty basic to some of you.
1. How much voltage will the generator on a SD-40 produce. Is there a max and a min. votage it is able to produce?
2.Are there circuit breaker between the drive motors and the generator? What are they rated at?
3.If a drive motor burns out or has a short can it be replaced quickly
4.how often is the electrical wiring replaced on a engine?
5.How often are the generators replaced on a engine? Do they go out often?
Thank-you
TIM ARGUBRIGHT

[edblysard]

Hi Tim,
I will give it a try, but I am sure there will be someone with a little more detailed answer.
1: First, its not a generator, its a alternator, just like in your car, only huge. It produces 600 volts a/c, the current is passed through a rectifier to convert it to d/c. Most produce up to 1800 amps,(electrical pressure), which is whats counts.
2: Yes, there is. Its called a ground fault relay, and trips if the traction motors or the alternator overloads or shorts. Rated to 600 volts.
3: No, its a real pain in the keister. Requires the locomotive to be in the shop for a day or two, depends on your shop force.
4: Almost never, unless its part of a entire class electrical upgrade, as in the SD40-2s, where the entire line of SD40s received modular electronics, and some of the older units were retrofitted at the same time. The -2 means the unit was either built with new, modular electronics, or is a older unit thats been upgraded, same with the GP38-2.
5: Again, almost never. We have had our MK1500 Ds for 7 years now, almost constant use, and have yet to lose a alternator. Funny, the alternators in our motors are made by...KATO.
Yup, the same guys who make model trains.
Even has the same logo on the data tag.
Stay Frosty,
Ed

[Jackflash]

Hi Ed, good answer, I,ve never measured the
voltage from a SD-40 altenator, but on a SD70MAC
the voltage can rise to 2600V and spike as high
as 3000V, also, by the way, in electrical terms
voltage is usually thought of as the "pressure"
jackflash

[edblysard]

Though amps were pressure, and volts were volume?
Oh well, either way, its a lot of juice to mess with.
Stay Frosty,
Ed

[Anonymous]

With that much voltage running thruogh a rectifier there has to be a lot of heat produced. What keeps the electrics cool? With the traction motors being so low to the ground how do they stay cool?
TIM A

[edblysard]

Traction motors have blowers, filtered and ducted to bring outside fresh air in and cool them. The rectifier and related "stuff" is in a compartment, usually right behind the cab, also with its own blower, filter and cooling system.
Stay Frosty,
Ed

[Jackflash]

Hi again Ed, Voltage is the measure of electron
pressure. Current,mesaured in amps, is the flow
of electrons. jackflash

[Soo2610]

Voltage and amperage sort of sounds like the size of a river and how high and fast the water is flowing.
As for cooling, I don't imagine it hurts to have someone named blysard in the cab keeping things nice and frosty!
Sorry Ed...Couldn't resist after the day I had. Needed a good laugh. No malice intended.

[edblysard]

None taken.
Every time the temp drops down here, well, you can guess how much fun the other guys have...
Stay Frosty,
Ed

[Soo2610]

Can guess more than you know. My last name is even more conducive to puns and witticisms than yours. Growing up was a lot of fun to say the least. Ask the right questions and I might even let you figure it out. Will have to think about it though since this is a public forum.