What is the oddest machine you have worked on or operated

[DutchInNZ]

It's been a long time (I'm retired now) but the rotating halves are going at the same speed, they just might not be in phase with each other. A common source was used to flash the fields and the output of the two generators fed a single breaker. You have two freewheeling AC outputs that would naturally sync up on the generator side of the breaker. There's no gearbox so the lagging side could easily come into phase, and then far as the output was concerned it was a single source. After that putting it online was the same as most gen sets, watch the synchroscope and have a sync check relay as safety backup. Although most PLCs do this automatically now, I've done it manually plenty of times.

How are reverse currents avoided when those two generators have a marginal difference in output voltage, or when a generator is varying against the net?

 

[MAX-24-Dean]

How are reverse currents avoided when those two generators have a marginal difference in output voltage, or when a generator is varying against the net?

Reverse current avoidence is a natural occurrence once the generators are sychchronized to the grid, or sychronized to each other. Its physics at work. The stronger (higher Mega watt) generator is the one that we would sync to. Once the 60 Hz (60 cycles per second) of the stronger generator has developed its magnetic field the weaker gen will just follow it when synchronized.
If they didn't sync when you tried to manually place them online with each other, you would know right away that you didn't get the right timing for the sycning. Lots of noise and vibration would occur. Hence currents being out of phase (reverse current then possible) that would literally cause the gensets to rattle and bounce making a seriously noisy racket. It could be a seriously scary event if you didn't know what is going on. Hands on the sychro switch at all times until you knew you have a smooth transition.

Thank God for PLC's and Instrumentation that takes care of this! I was part of a team for a time that all we did was bearing vibration analysis on generators prior to this automation.

 

[DutchInNZ]

Reverse current avoidence is a natural occurrence once the generators are sychchronized to the grid, or sychronized to each other. Its physics at work. The stronger (higher Mega watt) generator is the one that we would sync to. Once the 60 Hz (60 cycles per second) of the stronger generator has developed its magnetic field the weaker gen will just follow it when synchronized.
If they didn't sync when you tried to manually place them online with each other, you would know right away that you didn't get the right timing for the sycning. Lots of noise and vibration would occur. Hence currents being out of phase (reverse current then possible) that would literally cause the gensets to rattle and bounce making a seriously noisy racket. It could be a seriously scary event if you didn't know what is going on. Hands on the sychro switch at all times until you knew you have a smooth transition.

Thank God for PLC's and Instrumentation that takes care of this! I was part of a team for a time that all we did was bearing vibration analysis on generators prior to this automation.

I did mean when they are synchronised. Fabrication tolerances of the generators are, as with everything, unavoidable and will cause differences in output voltages, and that, even if it is just 0.5% or so, is bound to cause very high current from the higher to the lower because of the low internal resistance. In DC you block that with diodes, but in AC?

Sorry to the others to come here with such a specific rather off-topic question.

 

[Dennis Mohn]

Once I realized that the header said oddest rather than oldest machine you have ever worked on or operated I told my wife I was going to write about her being the oddest. I was told to be careful. Haha

ask forgiveness

 

[Dennis Mohn]

Does a 1893 'C' stamped hex receiver M1891 Mosin count? I believe this was the last year of manufacture in France, as the factory was getting rolling in Tula/Ishevsk. As a note, for anyone who hates 'garbage rods' the US was still using single shot trap door 45-70 Springfields at that time.

that counts

 

[Dennis Mohn]

Speaking of gas fueled tractors, can anyone tell me why the 20's till about in the 1960's, gas tractors were so common?

I'm not sure, but, I think it may have had to do with the availibity of gas engines and that gasoline was more common than diesel. The early tractors were actually made to run on what was referred to as distillate and the carbs were set up to warm the fuel from the exhaust manifold temp. to make it easier to atomize and ignite by the sparkplugs. Somebody out there correct me if I'm wrong

 

[joe48]

I Swear I read the thread title as "the Oldest" and now, I see it says "Oddest"....

I'll bet I have one that nobody else does. My first job out of college was in a foundry in the QC dept. testing iron samples, from there they put me in charge of the furnace dept. 22yrs old, one year out of college with 3 old timers working for me, and I'm responsible for two arc melt furnaces that could each melt 15 tons of iron. they had 3 x9" carbon arc rods in 5 ft. sections that screwed together. They ran on 100,000 volt DC current and iron would be heated to 2700-3000*F depending on type of iron needed. Thank God for those old timers and I made sure they knew I appreciated them, because they we're the only way I was successful in that job.
The other cool thing was I occasionally got to run overhead cranes, one was a 15 ton with a 5 ton electro magnet that was used for making up the scrap iron charges that went into the furnaces. Once I got good on that one several times I ran the big 40 ton in the main bay, control cab 35ft in air, even poured iron into molds several times.

 

[ArlyA]

I operated one of these, some years ago.

 

[USMC43]

Dad had late 40's cat D7 with cable blade and winch, a ww2 pull type scraper lifted with the D7 winch, and a number 12 motor grader from the late 40's . He also had a 1947 ATC crawler forklift that was very rare, spent more time using that actually than the others.

I have driven a 6-12 allis chalmers, 1922 if I recall correctly but it was just to move it for its elderly owner.

I have been the fireman for a Minneapolis steam engine as well one hot day to give the actual fireman a break. I don't think that counts as operating however.

Maybe a McCormick #6 horse drawn mower and New Idea hay loader putting up loose hay would actually be the oldest

 

[bigtiller]

I took the controls for an hour and was a great ride while it lasted.

I was the senior bidder on an electro-magnetic overhead crane in a large steel warehouse. I road around with the operator a bit to learn how things operate.

Then we discovered that paint color on the ends of the bundles of steel all looked the same to me. Color blindness disqualified me for that job.