understanding xformer

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Toros

Senior Member
Location
Tujunga, CA
hi
my client has a new industrial machine operating at 480v
and the available voltage-service in facility is 120/-240v, 4wire delta

Can I install an xformer: 480v-240v, 3-ph in reverse
(240v as primary and 480v as secondary)

or ,
I use an inverter
(240v as primary and 480v as secondary)
:?
????

Thank you
 

xptpcrewx

Power System Engineer
Location
Las Vegas, Nevada, USA
Occupation
Licensed Electrical Engineer, Licensed Electrical Contractor, Certified Master Electrician
hi
my client has a new industrial machine operating at 480v
and the available voltage-service in facility is 120/-240v, 4wire delta

Can I install an xformer: 480v-240v, 3-ph in reverse
(240v as primary and 480v as secondary)

or ,
I use an inverter
(240v as primary and 480v as secondary)
:?
????

Thank you

You can get a transformer specifically made for reverse (step-up) operation.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Because of potential problems with the voltage ratio under load and with the inrush current when energized, not all transformers are recommended by their manufacturer for reverse usage. Check with the manufacturer of the transformer you want to use.
In the US the NEC now requires that the transformer be marked or described as OK for reverse operation before allowing such use.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
You can get a transformer specifically made for reverse (step-up) operation.
:thumbsup:

These units usually have 480Y/277 secondaries, so it is easy to solidly ground it instead of leaving it ungrounded or corner grounded, both of which have application issues.
 
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