Allen-Bradley PowerFlex 70 Reference Manual

Determining Dynamic Brake Requirements 2-11
If the cycle cannot be adjusted, the decel time must be extended or the
system inertia lowered to reduce the average load on the resistor.
Another option is to use an external resistor.
Calculate the Percent Average Load. You will need this number to
calculate the Percent Peak Load.
Important: The value of AL should not exceed 100%.
This is the result of the calculation outlined in Step 6. Record this value
on page 3-1
.
This is the result of the calculation outlined in Step 6. Record this value
on page 3-1.
Now that the values of AL and PL have been calculated, they can be used
to determine whether an internal or external resistor can be used. Since
the internal resistor package offers significant cost and space advantages,
it will be evaluated first.
Percent Average Load AL 100
P
av
P
db
--------
×==
AL 100
40
40
----- 100%=×=
Percent Peak Load PL 100
P
b
P
db
--------
×==
PL 100
608.6
40
------------
× 1521%==

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