he authors of this page or responsible for its content.
catalog pdf
D
ONGAN
E
LECTRIC
M
ANUF
A
CTURING
C
O
.

2987 F
RANKLIN


D
ETR
OIT
,
MI 48207
800.428.2626

313.567.8500

F
AX
313.567.8828

www
.dongan.com
50
Buck - Boost Transformer - Sizing
Determine the information below in order to select
the correct buck- boost transformer for your
application. Reference tables, sizing formulae, kVA,
amps, and motor horsepower are provided on the
following page. Any questions on sizing may be
handled by your Dongan Representative or by
contacting Dongan Customer Service at
( 800 ) 428-2626.
Required
Data
Explanation:
Examples
Single
Phase
Three
Phase
Phase
Requirements
Determine load phase requirements
• Single phase
• Three phase
1
Phase
3
Phase
Line
Voltage
Determine the supply or line voltage at the installation site
where the transformer will be connected. This is best
accomplished by measuring the voltage with a suitable
voltmeter.
106
volts
208
volts
Load
Voltage
Determine the voltage you require to operate the load to be
connected to the transformer. If you are unsure of the correct
voltage, check the nameplate of the devices intended for
operation.
120
volts
240
volts
Frequency
Be certain the supply line frequency and the load frequency
required are the same. Remember: a transformer is not
capable of changing frequency.
60 Hz
60 Hz
Load Amps
or kVA
Determine either load kVA or load amps by adding all loads
to be supplied by the transformer. This is best accomplished
by again referring to the equipment nameplates.
4 kVA
15 kVA
Select
Correct
Catalog No.
from
Charts
Now turn to the appropriate single or three phase buck -
boost chart. Select the column closest to the line/load
voltage combination for your application. Move down the
column until values of load kVA or load amps meet or exceed
your load amps or load kVA required. Never size smaller
than your requirements demand. Then read across the row
to select the correct catalog number for your application.
Remember, three phase applications require banks of two or
three transformers, while single phase applications require
only one unit. The charts note the correct combination of
units required at the bottom of the columns. Be sure to
specify and order the correct number of units for your three
phase applications.
Cat No.
85-Y030
or
35-Y030
1 Unit
Required
Cat No.
85-Y040
or
80-Y040
2 Units
Required
Connect
Transformer
per Supplied
Diagrams
The transformer may now be connected per the diagram
indicated at the bottom of the column from which you
selected your line/load combination. A connection diagram
is packaged with each Buck-Boost transformer for your
convenience.
Diagram
SP-11
Diagram
TP-5