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Diesel-electric drive memories? thoughts? experiences?

Coaldust

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The Cat/Bucyrus/Terex deal was a strange one to follow. Cat decides to get out of the mining shovel game and sells the 5000 series to Terex, but spends 8.6B for Bucyrus and then doesn’t sell any shovels.
 

skyking1

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I see working letourneau log loaders every day. Those things always impressed me, they were built for the job.
 

Nige

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The Cat/Bucyrus/Terex deal was a strange one to follow. Cat decides to get out of the mining shovel game and sells the 5000 series to Terex, but spends 8.6B for Bucyrus and then doesn’t sell any shovels.
IMHO Cat wanted O&K (which was what the 5000-series shovel range ought to have been from the start - but wasn't), the rest of the Bucyrus deal was collateral damage as far as they were concerned.
 

Coaldust

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Nige,

I see. You have a good global perspective of the mine biz. How is the O&K excavator market doing nowadays, with the Cat dealer relationship?

Speaking of Cat and diesel-electric, I haven’t heard much about Progress Rail, EMD or the Caterpillar locomotive business, lately.
 

Nige

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TBH I have no idea. The areas where I've been over the past few years have been 100% Hitachi on big shovels for a considerable time. I know that Cat tendered for the shovel that I just put together, but with Hitachi already on site it was going to be an uphill battle.

I've kinda lost track with what's going on further South. Haven't been down that way for over 10 years now.
 

terex herder

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I had quite a few hours on a Wabco 111A paddle scraper. This was back in the late '70's/early '80's. Electric steer and electric chain drive, hydraulic bowl lift and eject. Biggest problem was the electric steering contactors dropping out from low voltage as you slowed for a turn. It didn't take long to figure out you slowed before a turn, and turned at full rack.

IIRC, the electric system was 240V 3 phase. However, it was a 120 Hz system, which allowed more power for a given size motor. The contactors had silver alloy contact buttons, and were expensive enough I just redressed them, never replaced any.

I was a youngster then and it was always interesting talking to old hands, as any mention of LeTourneau or electrics always brought out stories, ranging from scary to roll on the floor funny.

With the capabilities of modern day variable frequency drives and large scale experience from Tesla and other electric vehicle manufacturers I expect more tries at electric. Like any new venture, you can always tell the pioneers, they are the ones full of arrows.
 

Tones

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I had quite a few hours on a Wabco 111A paddle scraper. This was back in the late '70's/early '80's. Electric steer and electric chain drive, hydraulic bowl lift and eject. Biggest problem was the electric steering contactors dropping out from low voltage as you slowed for a turn. It didn't take long to figure out you slowed before a turn, and turned at full rack.
Have you run a D or C Pull, had an electric motor for each bowl function as well. I never experienced malfunctions with the contacts but the limit switches could be a problem. When the steering ones failed, usually one side, lead to some interesting moments. A mate had one fail on a hilly haul road, rolled twice landing on its wheels. He was ko'd when the windscreen hit him on the noggin. The mechanic fitted a new switch, while I cut a track in and it was driven out, checked over and put back to work. No ROPS in those days.
 

John C.

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I have some hours on C pulls. You forgot to mention the four speed manual transmission with the clutch. Never had a steering issue. The ejectors though tore through lots of wire rope when the limit switches didn't work.
 

Tones

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I have some hours on C pulls. You forgot to mention the four speed manual transmission with the clutch. Never had a steering issue. The ejectors though tore through lots of wire rope when the limit switches didn't work.

You can never call yourself a scraper operator until the you break off the gear shift lever on C pull ! :)
We used to weld them back on and keep on speed shiftin.
Yeah nah, I was to young for those. Everything was powershift when I started, suppose what the ole timers called "a spoilt brat".:D
 

Volvomad

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from what I remember, Johndeere stuck a genny in the middle of the tractor to power implements of a moderate power requirements. Something like 30% of engine power and could be used to power tools ,welders,etc.
What is the efficiency of diesel electric in optimum conditions?
Do any powershift dozers or haul trucks have converter lockups? Think some volvo loaders do .
The Fendt type CVT transmission doesnt seem to have made any inroads in construction equipment.
 

John C.

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As I recall, all the rigid frame and articulated trucks that I worked on in the nineties had lock up torque converters. The bigger Komatsu dozers, D375 that I know of had a lockup converter. The current version on the Cat D9, 10 and 11 have what they call something like an optimized drive train that has been explained to me as a lock up converter setup. I don't know that I've seen a CVT in any yellow iron so far.
 

Tugger2

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In the 70s i spent a year at Finning . They were big on the welding and fab side in the Port Hardy shop with Utah Mines Island Copper operation close by. There they ran Electrohaul trucks powered by 16V 149 s . We were tasked with rebuilding the boxes . They were loaded with electric P&H shovels ,thats a bucket we rebuilt with my pickup in it. Thats my experience with big electric machinery.
 

Nige

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As I recall, all the rigid frame and articulated trucks that I worked on in the nineties had lock up torque converters. The bigger Komatsu dozers, D375 that I know of had a lockup converter. The current version on the Cat D9, 10 and 11 have what they call something like an optimized drive train that has been explained to me as a lock up converter setup. I don't know that I've seen a CVT in any yellow iron so far.
All mechanical drive rigid trucks & ADTs still have lockup converters, certaoinly at least the Cat products do.

Lockup converters are useful in wheel loaders if they are used for load & carry operations of say 100m or more one way but a boat anchor for general loading operations. On larger loaders they are often an optional attachment but typically salesman don't know how or when to specify them. I've seen machines with lockup clutches truck loading, and machines doing load & carry that were crying out for a lockup clutch and didn't have one.

The current generation of D9-11 tractors have a combined torque divider/torque converter setup. The divider sends about 25% of the torque from the crankshaft directly to the transmission input shaft bypassing the converter completely, the other 75% is modulated via the converter. I wouldn't call it a lockup setup because there is no one-way clutch in the converter. I seem to recall one of the larger komatsu tractors (D375?) being equipped with a lockup clutch in carrydozer configuration but never worked on one.
 

Volvomad

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That torque divider sounds interesting. Had a quick look at Cat website . They seem to offer diesel electric and torque converter/powershift side by side . I would expect a lockup would be more economical than electric . When VME was put together the largest Euclid rigid truck was diesel eletric as per the volvo range catalog I had as a young fella . I always assumed they didnt make torque converters big enough to handle the power .
 

Nige

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Had a quick look at Cat website . They seem to offer diesel electric and torque converter/powershift side by side . I would expect a lockup would be more economical than electric.
Put simply, the profile of the mine haul roads goes a long way in determining whether mechanical or electric drive is the way to go for the haul truck fleet.
I always assumed they didnt make torque converters big enough to handle the power .
The 797 truck torque converter will handle 4000 HP.
 

robmcallan

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Support for the forner Unit-Rig electric drive trucks continues. I don't think they're actively pushing sales of new units at this time. The newest Specalog I can find online is 7 years old.
working in the oil sands in Canada. there are talks of cat having a sale of there 794 electric drive. while in the mine im at has 2 test 798 haul trucks. as for the cat C175 motor not to much else is cat. the biggest complaint is ride quality from the operators. they do leave the Komatsu and Liebherr in the rear view mirrors pulling any hills or getting out of the shovel pit.
that being said I was just apart of a 2 week shut down on one of the units. it had 11000hr on it and coming from cat mechanical truck background I thought the nosecone section they have on this electric truck is garbage instead of the dog bone set up they have with the 797 series trucks. also the steering and front suspension system is junk compared to the mechanical drive trucks. to many moving parts to wear out. Personaly I think if they take the frame work of the 797F truck and put in the electric drive system from the unit-rig it should be pretty bullet proof
 

Nige

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.......also the steering and front suspension system is junk compared to the mechanical drive trucks. too many moving parts to wear out.
Last time I had the chance of a close look at a Unit Rig truck in the field (when they were still badged as U-R) was many years ago, I think about 2005-ish. Compared to the Cat mechanical-drive line of haul trucks we were supporting at that time it looked as though it had been built by Fred Flintstone. I recall what the front struts & steering gear looked like and remember thinking hmmmmmmmmm....... :rolleyes::rolleyes:
 
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