How bespoke is this? Is there an alternative?

[Kennedy23]

Hi everyone. I'm looking for some advice on how bespoke this transformer is?

Output KVA: 2380
Connection: Ddoy11
Duty: 30sec/200min
Sec volts: 680/680
Sec amps: 1041/1041
Temp rise: 20deg/30sec
IP54
Type: DWound
3 phase
Frequency: 50Hz
PRM Volts: 11000
PRM Amps: 125
Cooling: AN AN
Ins class: H
% Z: 12

Is there anything that could be used in it's place that's more readily available?

The transformer has gone down & we're being told it's a 35 week lead time to replace, so desperately looking at whether we could hire something or buy something more readily available to replace it.

Thanks in advance for your help.

 

[R-fur]

I wouldn't say that is a standard transformer, have you tried Slaters in Newcastle or Winders in Leeds? they do secondhand units and may be able to help you.

 

[Kennedy23]

I wouldn't say that is a standard transformer, have you tried Slaters in Newcastle or Winders in Leeds? they do secondhand units and may be able to help you.

I haven't no - I'll give them a try, thank you!

 

[davesparks]

That's quite a big transformer with what appears to be an uncommon secondary voltage.

What exactly has 'gone down' about it?
Have you explored options for on-site repair?

 

[Kennedy23]

That's quite a big transformer with what appears to be an uncommon secondary voltage.

What exactly has 'gone down' about it?
Have you explored options for on-site repair?

I'm not 100% sure on the fault, but there's a large scorch mark inside the casing...insulation winding failure perhaps? We had HV engineers out to inspect & they have had to take it away to investigate. We're awaiting the inspection report for the exact issue. We have asked them to repair if possible, but they have said they won't guarantee any repair, if it's possible to do one (which I understand & don't have an issue with particularly).

We're looking at longer term replacement in full as everything is getting a bit long in the tooth, but we really can't afford a 35 week minimum downtime. It's a long justification process for the investment as well unfortunately.

 

[James]

it seems unusual to me,
if i am reading it right its about 2.4Mw but with a duty cycle of 30 seconds every 200 minutes

I presume this is for some special purpose, not a step down for distribution to general equipment.

 

[Kennedy23]

it seems unusual to me,
if i am reading it right its about 2.4Mw but with a duty cycle of 30 seconds every 200 minutes

I presume this is for some special purpose, not a step down for distribution to general equipment.

Yes it's for a very specific purpose, not general power

 

[James]

reading between the lines, you cant tell us what the application is and thats fine.
but wow, that must make something big, really hot in a short space of time.
bet it is quite exciting to watch.

 

[Kennedy23]

reading between the lines, you cant tell us what the application is and thats fine.
but wow, that must make something big, really hot in a short space of time.
bet it is quite exciting to watch.

No unfortunately I can't divulge what it's used for, sorry. But yes, it's pretty impressive to see! one of the reasons we're keen to get back up & running again as quickly as possible

 

[James]

I don't think you have many options, i think if it was my problem to deal with then I would,

A.
get the repair work underway as soon as possible, even if they cant guarantee it, they must be happy that the repair is safe and the transformer is safe to put back into service. even if they are not willing to guarantee it for any particular period of time.

at the same time

B. place the order for a new transformer, even if it is 35 weeks.
lets face it, it wont take more than a week or two for them to actually manufacture it, most of the wait is for a slot to fit it into the manufacturing schedule.

I don't know how much use it gets but realistically if they repair it then i would hope you have good odds of it lasting until the replacement is made.

If this is something that could cost the company in the 100's of thousands or more then some people might consider taking the MD of the transformer company (and his wife or mistress) all expenses paid to the Bahamas or similar for a week to discuss lead times.
you never know your luck, when you all get back there might have been an unexpected cancelation and they managed to fit in your transformer build whilst you were busy entertaining your guests.

 

[pc1966]

I was going to suggest R Baker (Electrical) Ltd but a quick check shows they only usually do up to 250kVA.

I'm sure all of us would like to hear how/when this is resolved!

 

[DefyG]

If this is something that could cost the company in the 100's of thousands or more

I'm surprised they don't have one on standby?

 

[pc1966]

I'm surprised they don't have one on standby?

I'm not. Seen a lot of unique test sets in my day where no quick alternative is ever in place.

To be fair, transformers are usually long-lived and reliable (accidental damage aside) so it is a lot of money to be sitting around "just in case". That presumes someone has worked out the cost of 35-weeks down time versus the depreciation cost of a spare...

 

[pc1966]

The 680/680V looks odd, is it two phase out instead of a star/delta output?

It might be you can get a 3-4MVA 11kV to 400V transformer as 2nd hand or something and then a separate LV unit to change that, but I really doubt the lead-time on the custom LV one would be any better, and it might need more design input as well on protection and volt-drop under load, etc.

 

[pc1966]

The 680/680V looks odd, is it two phase out instead of a star/delta output?

Actually trying to remember decades ago, but I guess "Ddoy11" given in the specs above should be Dd0y11 as it has two secondaries, one delta in phase (0 deg) with the HV delta primary (Dd0) and the second as star rotated to 30 degrees (11 oclock) as Dy11 ?

And both are 680V (the 680/680 bit)

So maybe feeding a 6-phase rectifier?

Hopefully someone like @Julie. can enlighten us!