Allen-Bradley PowerFlex 70 Reference Manual

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
oooooooooo[]
oooooooooo[]
-----------------------------------
100×=

Allen-Bradley PowerFlex 70 Specifications

General

Input Voltage	200-240V AC, 380-480V AC, 500-600V AC
Frequency Range	0 - 400 Hz
Humidity	5% to 95% non-condensing
Output Voltage	0 to Input Voltage
Control Methods	Sensorless Vector Control
Communications	Ethernet/IP, DeviceNet, ControlNet
Protection Features	Overcurrent, Overvoltage, Undervoltage, Overtemperature, Ground Fault
Operating Temperature	0°C to 50°C (32°F to 122°F)
Storage Temperature	-40°C to 70°C (-40°F to 158°F)
Enclosure Rating	IP20, NEMA Type 1