325Y/188 Volt Secondary Output

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infinity said:
Anyone have an idea what you would use a transformer with this output for?
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Never even seen a transformer like that. Heck Ive seen 69/120Y, 120 Delta, 208/360Y and 159/277Y but never this. Nor would I know anything close to using 188 or 325 volts that voltage.

But you have me curious :D
 
A new one for me. :)

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Hummm ....
Wild guess:
Says it has an electrostatic shield. Supplying a vfd for 50hz european motor? 324V is a bit low. Is it an older xfm?

ice
 
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Brand new but has been sitting in a warehouse for a while. Date code looks like November 2010.
 
Looking at it again it does say 460 delta, so at 480 you could get close to 200 volts. Perhaps with taps set high enough and a 480 volt line voltage one could obtain 208 volts phase to neutral? A computer server room feed in that most data units are often 208 volts phase to phase?
 
It's too new for my VFD WAG to be any good.

mbrooke said:
Same here. And thanks, now I can say I have indeed seen it all:D:p
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I'm sure I have not seen it all yet. But about this one - it is only one of the many things I am clueless about -- today. Tomorrow will have a new list.

ice
 
I like the idea of combining two different oddball situations to get the answer. I think iceworm was close, but limited himself to only one factor.
One route:
A. Korean (and other) 3-phase is 380Y/220.
B. A 380V 50Hz motor would need 380 x (5/6) to maintain the V/F ratio to operate at full load without a VFD. That is 316.
C. Not exactly 325, but close enough for me to specify it when the feeder to the motor is long and so has a high VD.
D. Same ratios, and same near miss, for a wye wound load.
 
PS: I find it very odd that some countries are listed as using 380Y/220 while others use 380Y/200. It does not seem possible for both of those to be right!
325Y/188 at least has the right ratio. :)
 
We used prob 12000 total like that from about 1970 to 1988 or so. We supplied 3 diff "std" secondaries: iirc 230, 275, & 330v wye - for our hi performance machine tool scr slide servo drives.

Fw rectified each phase into the dc pm motor lead, otherside of armature tied to X0
 
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GoldDigger said:
PS: I find it very odd that some countries are listed as using 380Y/220 while others use 380Y/200. It does not seem possible for both of those to be right!
325Y/188 at least has the right ratio. :)
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I agree, with a WYE secondary the numbers need to differ by a factor of 1.73.
 
GoldDigger said:
...
B. A 380V 50Hz motor would need 380 x (5/6) to maintain the V/F ratio to operate at full load without a VFD. That is 316. ...
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Wrong direction. 380/50 = a V/Hz ratio of 7.8:1, 480/60 = 7.67:1. You don't need a transformer to make a 380/50 motor to work correctly (albeit faster) when applied to 480/60.

I concurr with the OEM DC motor application for feeding a bunch of 1 phase BLDC motion control drives fed from older SCR based power units. They typically operated between 140-325VDC and need a 230V nominal single phase input that never goes lower than a threshold, 100VAC is common. But if you supply 240VAC from a common single phase supply, it can go too high if the input goes +10%. So you use an isolation transformer that gives you 188VAC single phase input to all of the rectifiers, because with 188VAC when rectified and filtered, even if the supply goes to 110% the DC can't be higher than 300V, and will never approach being as low as 100V even if fed with a 208V 3 phase supply. More modern servo motor drivers are all SMPS based and are no longer as sensitive to input issues, so this was likely a spare transformer for an OEM machine put on a shelf just in case, but when the system failed, it was replaced with something newer that no longer needed that transformer.
 
Jraef said:
....so this was likely a spare transformer for an OEM machine put on a shelf just in case, but when the system failed, it was replaced with something newer that no longer needed that transformer.
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With so many of these dc servos still in service on machine tools and other applications, there is still a huge number of these in use. We probably sell avg of 3 xfmrs of this size and voltage per year for burnt up ones where folks find it better choice to replace and get back running for $2000 instead of spending $6000 on new motor, drive, cables, re-engineering.... Only 3 per yr sold because these, like most xmfrs, are designed for 50-100yr life.... they only fail if someone lets a connection get loose and it overheats and burns stuff up, or a drive/machine fails in a really weird way and overloads the transformer. I'd wager we sell 1 for overload issue every 5 yrs, the rest of the 14 for loose connection that caused a fire and melt down. PM would have stopped these.... when we used to not sell alum wound xfmrs we used to tell customers they need to buy cu for the longer service life.... alum only will typically last 1/2 as long :)

PS: we probably have 3-4 of this size in the back warehouse still if anyone ELSE wants to bid on one!
 
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