Allen-Bradley PowerFlex 70

Determining Dynamic Brake Requirements 2-7
Step 5 Percent Average Load of the Internal Dynamic Brake
Resistor
Skip this calculation if an external dynamic brake resistor will be used.
AL = Average load in percent of dynamic brake resistor.
Important: The value of AL should not exceed 100%.
P
av
= Average dynamic brake resistor dissipation calculated in
Step 4 (watts)
P
db
= Steady state power dissipation capacity of dynamic brake
resistors obtained from Table A.A
(watts)
Calculate Percent Average Load of the dynamic brake resistor:
Record Percent Average Load of the dynamic brake resistor:
The calculation of AL is the Dynamic Brake Resistor load expressed as a
percent. P
db
is the sum of the Dynamic Brake dissipation capacity and is
obtained from Table A.A. This will give a data point for a line to be
drawn on one the curves provided in Section
3.
AL =
AL
P
av
P
db
--------
100×=
AL
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oooooooooo[]
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100×=