Classic Railroad Quiz (at least 50 years old).

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Posted by DSchmitt on Thursday, June 15, 2017 2:13 AM

daveklepper

This will be my last posting until (if ever) the Edit Button is restored.  I am 85 years old, have Dislexia, and do not wish to be suprised by making a statement the opposite of what I intended to make!  I need the Edit Button like handicapped and elderly Americans need long-distance train service.

You are entirely correct, described the situation perfectly.

 

Strange - I have the "EDIT" button on my post - and it works. Edited 12:15 AM 

I tried to sell my two cents worth, but no one would give me a plug nickel for it.

I don't have a leg to stand on.

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Posted by rcdrye on Thursday, June 15, 2017 7:30 PM

erikem
This so unnerved the North Shore lines master mechanic that he ordered the removal of the shunts.

All CNS&M steel cars including the Electroliners had at least some field shunts.  It was a feature of CNS&M's preferred Westinghouse HLF control (Hand acceleration Line powered Field control)  The "Woods" had GE type M.  Not particularly technical explanation of Field control is that weakening the "Field", or outside windings of the motor, the Armature becomes relatively stronger, and can operate at a higher speed.  CNS&M's standard Westinghouse 557R5 motors allowed two steps of field weakening, I think the Electroliner's original control allowed four, though only two were used in service.  The last steps of field weakening were supposed to be applied automatically when the controller was in the last notch, so may have been an auxiliary system.

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Posted by erikem on Thursday, June 15, 2017 10:42 PM

The story in Middleton's book made it pretty clear that the shunting used in the 111MPH run was not implemented when the cars were delivered. It could very well be that the work done for the test was either connecting the last two steps of shunting or increasing the amount of field that was shunted.

The whole purpose of the shunt was to allow the armature to carry more current at the higher motor speeds for a given voltage on the motor terminals (the back EMF is proportional to the field strength times the motor speed). With a DC series motor operating below the field saturation current, doubling the speed would require the armature current to halve in order to maintain the same terminal voltage. This means the torque (and tractive effort) will go down by a factor of four and the motor horsepower will go down by a factor of two. With a 50% field shunt applied in this situation, the armature could continue to draw the same current and thus keep the horsepower the same with only a factor of two loss in torque.

IIRC, some of the Milwaukee electric locomotives had ~35% tap on the fields.

For DC electrifications in the pre-chopper days, the use of field shunts increased the number of available running speeds. For the CNS&M, that meant they could run the Electroliners at 85MPH where they could while maintaining the ability to run at a somewhat slower speed without having to cycle the controller between accelerating and coasting. FWIW, choppers effectively do cycle rapidly between acceleration and coasting.

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Posted by daveklepper on Friday, June 16, 2017 1:47 AM

Thanks, D:   You have indicated to me that the moderator is discriminating against me.  Which I suspected.   And the reason that he is can only be because I referenced what rabbis said instead of someone else on a matter that is not specifically religious, life in outer space and how it reflects railroads.  He removed the thread in spite of the fact that the subject was not specifically religious.  Possibly because someone objected.

So I have made an exception regarding my last post to let you know about this sitiuation,

I have no objections to review of posts before posting.  I do object to being denied the edit button, and a review of past posts indicates it is necessary.

And I still have no idea whether this post will appear without spelling mistakes.

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Posted by wanswheel on Friday, June 16, 2017 11:37 AM

daveklepper

sitiuation

Dave, it's great to see you post again. I'm very sorry you lost your father, 62 years ago yesterday. The NY Times, June 16, 1955:

https://archive.org/stream/leadersoftwentie00mend#page/132/mode/2up

Mike

RME
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Posted by RME on Friday, June 16, 2017 8:52 PM

erikem has, in fact, a better answer than I did.

 

Mr. Klepper: your account still shows up as current, so the only way you'd fail to see an 'edit' would be if you posted using a different account, or deleted cookies after posting the original.  If the problem is systematic, contact Kalmbach forum customer service, describe the situation analytically, and they will help you fix it.

 

To my knowledge there is no way a moderator can deny editing to a poster without completely banning them ... perhaps not even then.  So this is anomalous and not likely any form of intended or circumstantial discrimination.

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Posted by daveklepper on Sunday, June 18, 2017 4:34 AM

OK.   I have complained by email to Jim Wrinn, but not gotten any reply.  I do note that my complaint - explanation posting did get posted without spelling errors, or at least none that I can recognize.  The problem may be with my servers in Israel and have zero to do with Kalmbach.  A similar problem also occurs with my regular email, primarily on Yahoo.  I double-check that I send something with the right email address, am certain that the email address is correct, then get a notice from Yahoo that the message was not delivered, then check the address on the non-delivery message, and note that one letter was missing from the address.

I checked prior posting before writing this, and still did not find the Edit Button.

 

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Posted by daveklepper on Sunday, June 18, 2017 8:45 AM

And thanks Mike and RME!!

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Posted by daveklepper on Sunday, June 18, 2017 8:51 AM

And are not we waiting for a question from Erikem?

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Posted by Firelock76 on Sunday, June 18, 2017 10:45 AM

Wow, what a distinguished looking man your father was David!  I wish I could grow a moustasche like that!

The best I've been able to manage is like Dr. Bridgman's.

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Posted by erikem on Sunday, June 18, 2017 2:39 PM

daveklepper

And are not we waiting for a question from Erikem?

Yep, I've been busy with my son's H.S graduation festivities... He will be off to UCSB in the fall.

Question: What was the highest voltage used for a DC electrification and what was the trick used to make it possible? Exra credit:  What was the trick used to power the auxiliaries?

Another note related to series motor field shunting/tapping: The tradional method for getting variable speed operation with a DC shunt motor was to use Ward-Leonard control, where low speeds would be constant field and variable armature voltage, and high speeds would be variable (reduced) field and constant armature voltage. Some of the early gas-electrics used Ward-Leonard control and the ASEA/EMD AEM-7's used Ward-Leonard control implemented with thyristors.

WRT to Middleton's Traction Classics, vol 2, I bought the book not too long after it was published from the OERM bookstore and didn't get around to reading the chapter on the Electroliner's until maybe a year ago. The story of the 1950 tests with the field shunting stood out, so it ws easyt to answer RME's question.

 - Erik

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Posted by daveklepper on Monday, June 19, 2017 1:25 PM

Replying, the highest much-used voltage DC was 3300 (approximately, somewhat more than the more usual 3000) on some Russian electrifications, and some may be in use today. Usually, accessories were powered by a motor-generator producing a low voltage with battery charging capability.   Some locomotives used motor-generators for traction power as well, for lower voltage to the motors, but some a motors were wound for as high as 1650 using many turns of thinner wire on both armatures and field coils with very specially designed commutators, with offset contacts allowing considerable insulation between segments.  In other words, there were several paths for brushes, alternately contacting copper or brass and then hard insulation.

And I do not remember the source for what is either iinformation or misinformation; you probably know the details much better than I do.

3300 volts were used by some other countries as well. In Eastern Europe.

And I just used the Edit Button to add this comment!

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Posted by erikem on Monday, June 19, 2017 2:05 PM

daveklepper

Replying, the highest much-used voltage DC was 3300 (approximately, somewhat more than the more usual 3000) on some Russian electrifications, and some may be in use today.

While correct with the "much-used" disclaimer, there was one experimental installation with a significantly higher voltage (this is the one I'm looking for). GE had proposed this higher voltage as an option for the Milwaukee electrification. Overall system costs would have been about the same for both voltages, with the increase in locomotive costs eating up the savings in reduced feeder/substation costs.

Using an m-g set for auxiliaries was not practical at the higher voltage, so another approach was used.

The Milwaukee did up the trolley voltage to 3300 in the late 1940's and early 50's.

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Posted by rcdrye on Monday, June 19, 2017 3:58 PM

Not sure about the highest voltage, but low-voltage auxiliaries on streetcars and interurbans often used the voltage drop across the air compressor to get a voltage that could be used to charge batteries.

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Posted by erikem on Monday, June 19, 2017 5:09 PM

That's getting close to what was done in the experimental installation, but note that the air-compressor was one of the low voltage axiliaries...

Rule of thumb for commutators on DC machines is that the potential difference between bars should not exceed 20V. That means a four pole motor wound for 1500V would need at least 300 bars in the commutator.

The equipment in the installation I'm looking for used four motors and has series/parallel control, in this case either four motors in series or two sets of two motors in series with the sets in parallel.

 - Erik

RME
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Posted by RME on Monday, June 19, 2017 10:56 PM

erikem
While correct with the "much-used" disclaimer, there was one experimental installation with a significantly higher voltage (this is the one I'm looking for).

I can't find the Alexanderson research that Armstrong hinted at in his discussion of DC vs. split-phase in 1914, but I should at least mention this later alternative for people who might not have seen it.

I do have an answer of sorts to the question: it's shown on what's left of this sign from the aftermath of the GE 6-pole rotary-converter experimentation...

 

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Posted by daveklepper on Tuesday, June 20, 2017 8:01 AM

yeh, if this was much higher than 3000 or 3300 volts, was this two wires with one positive and one negative with respect to ground?

And you can reduce the number of commutator bars having more than one ring of brushes and bars, with insulation bars between the conducting bars, as I described.  The much-much wider gap for insulation allows much higher voltage, as much as 100V instead of 20V.  Much higher than that and you wil get arcing as the brush leaves the conducting bar for the insulation bar.  But you also have to watch the current to avoid arcing.

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Posted by erikem on Tuesday, June 20, 2017 4:04 PM

The installation used a single trolley wire with the track rails used for current return.

A couple of clues: The installation was done by Westinghouse and a mercury arc rectifier was used to convert AC to DC. The installtion was completed before major work was started on the main Milwaukee electrification.

A side note on 3000/3300VDC electrics - GE made a late 1969 proposal to the Milwaukee for modern 3300V C-C locomotives that had about the same continuous rating as the Little Joes. One signficant change in motor construction between 1950 and 1969 was using Kapton for insulating the armature conductors with a 30% increase in continuous current rating. The proposal said that the motor used by the internal M-G set was a 2 pole motor to allow for operation directly off 3300VDC.

 - Erik

RME
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Posted by RME on Tuesday, June 20, 2017 5:52 PM

Grass Lake line of Michigan United Traction Company?  (Covered in Electric Railway Journal, V.XLVI, n.14 (Oct 2 1915) p.660ff)  This followed internal Westinghouse testing at East Pittsburgh in 1914 all the way up to 7000V on the trolley wire.  Duffy says that Machefert-Tassin, Nouvion, and Woimant, in Histoire de la Traction Electrique, mention a test between Kalamazoo and Grand Rapids at around this time with 5000V on an isolated third rail, which would be highly interesting to see... this is the famous 2400V on 80lb rail setup, but I think the reference is confusing the insulator test values with an actual traction test at that power.

Apparently the auxiliaries were run off a 150V storage-battery bank that charged in series with the four 100hp traction motors (!) which had double armatures geared to a common axle (!!)  Traction current was reportedly only about 30A peak per motor, so this is less extreme than you might think.

Not one mercury-arc rectifier; three.

And to add further amusement, the car was completely compatible with normal 600V DC power...

Potter of GE apparently tested BA&P equipment at this same 5000V, but I can find nothing but anecdotal discussion of the testing. 

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Posted by erikem on Wednesday, June 21, 2017 1:17 AM

That's the answer I was looking for. (Your turn)

The first reference that I saw on the Grass Lake line was in Hilton & Due's book on Interurbans (bought my copy in 1978). There was almost no detail on the installation in the book and got my info from either a 1914 or 1915 volume of The Electric Journal. The Internet Archive has scans of those two volumes (and more) in various formats along with scans of the General Electric Review. Both the Journal and Review are good resources for the technology used in the early electrifications.

The other amzing thing about the experiment is that the equipment seemed to be pretty reliable. Unfortunately this came at the end of interurban construction, so never got past the experimental stage.

The motors for the Milwaukee electrics were tested to an equivalent of a 4500 volt trolley potential with no ill effects.

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Posted by daveklepper on Friday, June 23, 2017 12:32 AM

And the next question is?

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Posted by Miningman on Saturday, June 24, 2017 9:30 PM

Nobody around going on 2 days anywhere on Classic Forum. Not good. 

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Posted by rcdrye on Sunday, June 25, 2017 8:46 AM

Where are you, erikem?

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Posted by Miningman on Sunday, June 25, 2017 6:18 PM

Is it not RME's question? I'm confused!

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Posted by rcdrye on Sunday, June 25, 2017 6:30 PM

Sorry.  Where are you, RME?

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Posted by erikem on Monday, June 26, 2017 10:19 PM

rcdrye

Where are you, erikem?

 

In between work and login problems with the forum, haven't had much of a chance to check in.

BTW, I did see your post on the whereabouts of RME.

 - Erik

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Posted by RME on Tuesday, June 27, 2017 1:35 AM

Even more work on my end, combined with q relative lack of interesting questions.

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Posted by Miningman on Tuesday, June 27, 2017 1:41 AM

 In the interim, here is one. We will still await RME in the future.

What is significant about this GP7? 

 

 

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Posted by rcdrye on Tuesday, June 27, 2017 7:00 AM

GMD-built?  With a 3000-series number, it's ex-Wabash.  First GP7 in Canada?  As far as I can tell it's Wabash's only GMD GP7 (though Wabash did have F7 sets built by GMD)

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Posted by Miningman on Tuesday, June 27, 2017 8:37 AM

Toronto Hamilton and Buffalo #71 was the first GP7 built in Canada. 

You are very close with the answer. It is GMD London built, it is ex-Wabash and was built for them, it was their only one, a sole unit among 22 F7's but go one step further for the answer.

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