Tap position VS Impedance

MG:

OMS, I have had a 415V transformer previously, however it is far more better to have a design package which includes for some custom made parts from a specific manufacturer rather than 2-3 different providers with a nightmare of coordination and discussions with them, i just know it wont work.


Surprisingly the 433V transformer is also a bit smaller which helps with the transformer room clearances which are already a problem.

I'm not sure I follow the logic here, Mike - far more better, how ?


A 433 secondary is a specific transformer developed for the power distribution sector (as I mentioned, ENATS usually). If you want a "euro" transformer, then that's usually also an off the shelf unit (typically offered as 415V to 420V). With a 6% impedance unit you have manageable fault levels and a full load voltage depression of circa 25 volts - which puts you around 390Volts at the source "terminals" under full load amps.


If you want an example, I'm looking into what may be a design claim against a consultant who specified 433V Units for a manufacturing facility. Much of the equipment derives from Germany, and is stated at 220V - it is also equipped with over voltage shut off  - guess what, under low load conditions the machines are tripping on over voltage - a lot of "product" is being lost, and the owners want to know why they don't have a system that works with their machines.


Nothing wrong with specifying 433V secondary by the way, it just seemed a curious (to me) approach if you intend to tap down anyway


Regards


OMS

MG:

OMS, I have had a 415V transformer previously, however it is far more better to have a design package which includes for some custom made parts from a specific manufacturer rather than 2-3 different providers with a nightmare of coordination and discussions with them, i just know it wont work.


Surprisingly the 433V transformer is also a bit smaller which helps with the transformer room clearances which are already a problem.

I'm not sure I follow the logic here, Mike - far more better, how ?


A 433 secondary is a specific transformer developed for the power distribution sector (as I mentioned, ENATS usually). If you want a "euro" transformer, then that's usually also an off the shelf unit (typically offered as 415V to 420V). With a 6% impedance unit you have manageable fault levels and a full load voltage depression of circa 25 volts - which puts you around 390Volts at the source "terminals" under full load amps.


If you want an example, I'm looking into what may be a design claim against a consultant who specified 433V Units for a manufacturing facility. Much of the equipment derives from Germany, and is stated at 220V - it is also equipped with over voltage shut off  - guess what, under low load conditions the machines are tripping on over voltage - a lot of "product" is being lost, and the owners want to know why they don't have a system that works with their machines.


Nothing wrong with specifying 433V secondary by the way, it just seemed a curious (to me) approach if you intend to tap down anyway


Regards


OMS