W-L, transductors, SCR?

[Skogsgurra]

Drive technologies have changed over the years. From Ward-Leonard, Mercury Rectifiers, Transductor Controlled Rectifiers, Thyristor/SCR drives to PWM VFD:s, which are now totally dominating the drive market.

I had a visitor last week that is developing drives with SiC components. He is deeply involved in that technology and we discussed different drive technologies. SiC has a lot going for it and it looks like it will be more common within the next five or ten years.

I know that there are old W-L drives out there. There are also some transductor drives (aka Magamp drives). And there are surprisingly many DC drives with thyristor control. I know that because we get phone calls from guys looking for spare parts or help with those old drives. Some of them are more than fifty years old and that makes me wonder if it is just us or if there are really lots of vintage drives still doing their job out there.

The questions seem to be:

1. Do you see any vintage drives in your neck of the woods?
2. What technology are they?
3. What applications? (fans, pumps, steel, paper&pulp, machine tools, locomotives, ships, petroleum etcetera)
4. How many motors are typically connected to each drive?
5. What power are the motors? The whole system?
6. Are vintage drives still being used in company critical applications?
7. Will they soon be replaced by modern drives?
8. If not - is there a specific technological reason for that?
9. And last: Have you encountered any special or exotic drives (like cascade, matrix, CSI, SiC etcetera) lately.


Sorry for the inconvenience. But it would be really interesting to know. And, if there are other questions that should be in the list - please add them and comment on them.

Really looking forward to your answers. I don't think that an enquete like this has never been carried out before. Or has it? Any references?



Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[sibeen]

OK, first off I'm annoyed that a Swede is teaching me a new word in English, and at my age.

Enquete, thanks for that one, Skogs, must put it to use one of these days.

I've never been a drive person much, more a UPS and DC for telco applications. Worked for a company called Thycon in the 80s which used a CSI inverter in a UPS application. It was a variation on an older ABB furnace drive with a twist to handle the frequency variations and the requirement to sync to an incoming source.

On the DC side I was involved in the replacement of a 50 kW system a few years ago where the original was from the 70s and used a diode bridge and an upstream motorised variable transformer. The output was the standard telco 50V and the secondary of the transformer was basically a variac into a diode bridge. It was forty years or so old and still running like a champion, just that it was quite inefficient, and if it had gone pear shaped the parts had all been used up and there was no one who had any experience working on it. The new rectifier took up approximately 10% of the real estate of the old. I must admit it was fun just looking over the old beast.

 

[waross]

Hi Gunnar;
Is this a new overall drive design or is it baically the same PWM system with more efficient power transistors and associated drivers.

sibeen:
I thoght the same. I googled the word to understand the nuances before using it in conversation.

http://www.oxforddictionaries.com/translate/french-english/enqu%C3%AAte[/URL]]Share this entry
enquête
Pronunciation: /ɑ̃kɛt/
Translation of enquête in English:
f

1 [Law] inquiry, investigation; (into a death) inquest enquête de police police investigation
In Other Dictionaries

2 (by journalist) investigation
In Other Dictionaries

3 (by sociologist) survey
In Other Dictionaries

Still a good word, Gunnar. I'll still try to drop it into a conversation.
"Has ther ever been an enquête into the percentage of patrons choosing a la mode deserts at buffets versus smorgasborgs?" Grin

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[crshears]

At this page

http://www.opg.com/generating-power/hydro/ottawa-st-lawrence/Pages/rh-saunders-station.aspx

you will see a photograph of the RH Saunders / Franklin Delano Roosevelt Generating Station that spans the St. Lawrence River [and the Canada/US border] between Cornwall, Ontario and Massena, New York; the site is one of my almae mater [a former employment location].

Clearly discernible below the breast wall of the power dam itself are a pair of gantry cranes; the one on the left is the FDR unit belong to the Americans [I know next to nothing of its technology], and the one on the right belongs to the Canadians, specifically Ontario Power Generation. This gantry crane employs a 1950s era Ward-Leonard system for all of its translative motions, viz., to move the entire unit toward or away from the border, to move the main hook and its hoisting gear upstream or downstream within the crane itself, or to raise or lower the main hook itself. Only one motion can be performed at a time, using a series of control relays and contactors to provide the required interlocking functions and perform the necessary switching to achieve directionality. By means of this equipment truly creeping speeds can be obtained, and translations as small as 1/16" are easily obtainable in all axes. Recall dims, but I believe that around the time I left there were plans afoot to add encoders that would provide the operator with very precise feedback of all translative motions to enhance controllability.

By means of opening a slab overhead door, the entire crane can be moved into the erection bay, something that greatly facilitated rewinding the generating unit's stators in a climate-controlled environment.

If memory serves, the main hook is rated to hoist 300 Imperial tons. The two auxilary cranes witin the unit are used for hoisting the lighter items out of the turbine pits; these are powered using much simpler WRIM's. The power supply to the crane is via a 3-phase 600V supply contact bus; the crane is equipped with collector fingers for power import.

Interestingly, the American crane is also supplied at 600V via a step-up transformer from their 277/480V station service; because of this, either entitiy can loan their gantry crane to the other, should the need arise. A peculiarity of this site was, for many years, that if one entity borrowed the other's crane, the Customs agencies had to be summoned to thoroughly search the crane in question for stowaways, since the crane was, by definition, "a motorized vehicle crossing the US/Canada border." Weird, huh? This requirement was finally waived.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[cswilson]

Not directly related, but I have noted that there is a thriving market on Ebay for the obsolete versions of our servo controllers. A couple of our distributors monitor these postings regularly and buy up anything that appears to be working. They can get them cheap and sell them dear to someone who is down, more than covering the often long and unpredictable holding costs.

Does anything like this happen for drives, or even drive components?

 

[ScottyUK]

I saw it with Sun Ultra 1 and Ultra 2 workstations a few years ago - the last of the proprietary S-Bus generation, before Sun went over to PCI - because these machines were needed to operate the Westinghouse WDPF II turbine controllers. Emerson wanted absurd amounts of money for what was almost always a PSU fault. Many customers were happy to gamble a more modest amount on either a salvaged PSU or a working workstation.

 

[flexoprinting]

Hi Gunner

Our three oldest Envelope converters came with Louis Allis- Saber 3306 DC drives from the OEM, 230V supply max output 37 HP connected to 25 HP motor. Two
of the drives were replaced and one still in service. We found it easier and faster to replace the failed drives than to have the old one's repaired.

Chuck

 

[Skogsgurra]

Thanks all! Interesting insights. But we need many more inputs before any conclusions can be drawn. So, even if you think that the information you have isn't very interesting, it will be interesting when combined with lots of other guys information.

Just keep it coming!


Sorry for the funny word.
That is what happens when words "leak" from one language to another. I did not understand that enquete isn't used much in English. We have that word in Swedish and French. And I was off guard.
Also, I think I shouldn't have said: "I don't think that an enquete like this has never been carried out before" It shall be "ever" shan't it?

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[crshears]

Almost...

I'd write it as "It should be 'ever,' shouldn't it?" since to my etymology shan't is a contraction of shall not, which is an imperative, not a conditional or interrogatory...

And yes, with the sentence constructed as it is the word should be "ever," not "never."

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]