GP40 upgrade idea

[daylight4449]

now recently i submited to the providence ansd worcester railroad. here's my idea. my thought was to, instead of running the connections directly from the alternator to the traction motors, run them through a switchboard in the cab, and then to the traction motors, thus allowing the engineer or operation crew to turn traction motors on and off when needed. initally, i thought of submiting the idea to the union pacific, seeing that i initally planned to use the prinipals on a DD40X, but i had to start somewhere, and apparently the P&W is interested with the prospect. whats even better is that the idea can be applyed to a B40-8 or other locomotives in on the P&W roster.

[D.Carleton]

now recently i submited to the providence ansd worcester railroad. here's my idea. my thought was to, instead of running the connections directly from the alternator to the traction motors, run them through a switchboard in the cab, and then to the traction motors, thus allowing the engineer or operation crew to turn traction motors on and off when needed. initally, i thought of submiting the idea to the union pacific, seeing that i initally planned to use the prinipals on a DD40X, but i had to start somewhere, and apparently the P&W is interested with the prospect. whats even better is that the idea can be applyed to a B40-8 or other locomotives in on the P&W roster.

And what is the cost/benefit of this idea?

[rdganthracite]

now recently i submited to the providence ansd worcester railroad. here's my idea. my thought was to, instead of running the connections directly from the alternator to the traction motors, run them through a switchboard in the cab, and then to the traction motors, thus allowing the engineer or operation crew to turn traction motors on and off when needed. initally, i thought of submiting the idea to the union pacific, seeing that i initally planned to use the prinipals on a DD40X, but i had to start somewhere, and apparently the P&W is interested with the prospect. whats even better is that the idea can be applyed to a B40-8 or other locomotives in on the P&W roster.

Have you not heard of a traction motor cutout switch? What you are proposing already exists and is used to take a motor out of service when there is a problem.

[CN Sparky]

As rdganthracite posted, this already exists...

But if it didn't, I'm not sure that running a whole slew of 500MCM cables into the cab (along with the appropriate heavy-duty switches to be able to handle the amount of power that the traction motors) - within reach of the crew, who can't seem to keep their sheets and cups of water, etc, out of the existing electrical cabinets - is a very good idea.

[DutchRailnut]

Cutting out traction motors would not save you energy or fuel so what is purpose ???
And as said before the traction motor cut out switch already exist , no it has no big cables attached just control voltage to each set of line contactors controlling each traction motor.
By cutting out traction motors you also cut out wheelslip protection , auto sanding etc.

[daylight4449]

Cutting out traction motors would not save you energy or fuel so what is purpose ???
And as said before the traction motor cut out switch already exist , no it has no big cables attached just control voltage to each set of line contactors controlling each traction motor.
By cutting out traction motors you also cut out wheelslip protection , auto sanding etc.

ok, but what i'm proposing is a system that can adjust traction motors between full and completly inactive.

[daylight4449]

besides i theroize that it could at least add a few days between traction motor replacement/overhaul and could give a longer lifespan to the gearboxes. like i said, it was originally meant for a DD40X, although it could be used on a AC6000 or SD90MAC, or even genset units or slugs.

[D.Carleton]

ok, but what i'm proposing is a system that can adjust traction motors between full and completly inactive.

I'm still not understanding this. Could you give us a hypothetical situation describing the challenge and how this upgrade would resolve the challenge? Saving a few hours or days of traction motor/gearbox wear does not immediately sound like justification for a major (expensive) upgrade.

[CN Sparky]

ok, but what i'm proposing is a system that can adjust traction motors between full and completly inactive.

I believe the handle known as the "throttle" achieves this already

[daylight4449]

scenario:
The Union Pacific has to use a AC6000 on a local freight. while it's great for moving the consist, it's no good at switching the industries along that branch. although recently a system that would allow the traction motors to be turned on and off was installed, meaning that an overpowered brute like a AC6000 to be used on branch line switching opperations.

now do you see where i'm coming from?

[rdganthracite]

besides i theroize that it could at least add a few days between traction motor replacement/overhaul and could give a longer lifespan to the gearboxes. like i said, it was originally meant for a DD40X, although it could be used on a AC6000 or SD90MAC, or even genset units or slugs.

A cut out traction motor is still connected to the axle and is still turning. While there is reduced stress on the gear teeth there is still wear on the bearings and on the brushes for a DC motor.

[DutchRailnut]

Also for example, if you got a 2000 Hp unit which normally puts 500 hp to each traction motor, after cutting out a traction motor, the 3 remaining traction motors share the full 2000 hp

[conrail_engineer]

The newest models with computer controls already automatically cut out traction motors during slow, light-throttle movements.

Beyond that, all you'd do is increase wheel slip and lower tractive effort. Fuel is used by the prime mover; and how much fuel it uses depends on LOAD.

Whether that load on the alternator is with two traction motors, six, or twelve (with a slug attached) isn't going to be drastically altered. What matters is how much weight has to be moved; and how much power goes through the traction motors to effect this.

Designers are aggressively attacking the question of fuel usage; and some of their solutions are surprising. The newest GEs, for example, seem to have only three positions on their electronic governors: About 400 rpm; about 800 rpm, and 1047 rpm (full throttle). All that's varied as the engineer goes through the notches, is the exciter; how much current is allowed to the traction motors.

After all, it isn't RPMs that use fuel; it's LOAD on the motor. A diesel engine is most effective in a narrow band of RPMs; and designers apparently decided to work with that characteristic rather than have the engine speed inch up with each change in throttle position.

[FarmallBob]

...Fuel is used by the prime mover; and how much fuel it uses depends on LOAD.

Whether that load on the alternator is with two traction motors, six, or twelve (with a slug attached) isn't going to be drastically altered. What matters is how much weight has to be moved; and how much power goes through the traction motors to effect this.

Agree - it's basic physics.

Designers are aggressively attacking the question of fuel usage; and some of their solutions are surprising. The newest GEs, for example, seem to have only three positions on their electronic governors: About 400 rpm; about 800 rpm, and 1047 rpm (full throttle). All that's varied as the engineer goes through the notches, is the exciter; how much current is allowed to the traction motors.

I suspect this may done also to help meet Tier 3 emission requirements.

Turbocharged diesel engines – all current production locomotives - emit the most particulates (smoke) during the several seconds between the throttle is notched up and when the turbocharger “catches up” to the new higher RPM/load. (Classic example is the trademark Alco eruption of oily black exhaust when first throttled up.)

By reducing the number of possible RPM settings from 8 to 3, then grouping 2 or 3 throttle notches into each RPM setting, the frequency of RPM increases is reduced as the throttle is worked up and down. Hence particulate emissions will also be reduced.

Unfortunately however this doesn't make for as impressive trackside photos...

[lvrr325]

initally, i thought of submiting the idea to the union pacific, seeing that i initally planned to use the prinipals on a DD40X, but i had to start somewhere, .

Overlooked in all this is the fact that the Union Pacific only rosters one DD40AX "Centennial" series locomotive, the remaining existant units are all stuffed and mounted. It's primarily used for special occasions although it has served in general freight service. There would be little to no economic benefit to greatly modifying this single remaining locomotive.