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fi
eld, IL 62711-6228 • 217-483-1600 • Fax 217-483-1616
Lbdman8p.indd (04/11) • © 2011 Simplex, Inc. All Rights Reserved. • Printed in the USA. • www.simplexdirect.com
LOAD BANK MANUAL • LBD Series • page 13 of 16
The following calculations are used to
determine the amount of current when
the desired amount of kilowatts is ap-
plied at 1.0 power factor.
3 Ph a s e
1. Multiply the desired amount of kilo-
watts to be applied by 1000.
2. Multiply the operating voltage times
the square root of 3 (1.732)
3. Divide the answer of step #1 by the
answer of step #2.
4. The answer of step #3 is the average
line current with the desired kilowatts
applied at 1.0 power factor.
S i n g l e p h a s e
1. Multiply the desired amount of kilo-
watts to be applied by 1000.
2. Divide the answer of step #1 by the
operating voltage.
3. The answer of step #2 is the average
line current with the desired amount
of kilowatts applied at 1.0 power fac-
tor.
The following calculations are used to
determine a step kilowatt rating at other
than a rated voltage. This is accom-
plished by referencing the load step to
a KW value at a known voltage.
1. Determine the new unrated operating
voltage.
2. Divide the new operating voltage by
the reference voltage.
3. Square the answer of step #2.
4. Multiply the answer of step #3 times
the reference kilowatt value of the
load step which the new kilowatt
rating is desired.
5. The answer of step #4 is the kilowatt
rating of the load step at the new
voltage.
EXAMPLES
When desired amount of kilowatts is applied at 1.0 PF:
3 Phase
Applied: 50KW
Operating Voltage: 480V
Amperage =
KW x 1000
Volts x 1.732
=
50 x 1000
480 x 1.732
=
50,000
831.36
=
60.1
Single Phase
Applied: 25KW
Operating Voltage: 240V
Amperage =
KW x 1000
Volts
=
25 x 1000
240
=
25,000
240
=
104.2
Determining step KW at other than rated voltage:
Applied: 80KW
Operating Voltage: 450V
Rated
Voltage:
480V
Step KW = (Oper. Volt.
÷
Rated Volt.)
2
x Applied KW
=
(450
÷
480)
2
x 80
=
.9375
2
x 80
=
70.3
