Braking Energy Calculation - ABB MicroFlex e190 User Manual

Braking energy calculation

The following calculations can be used to estimate the type of brake resistor that will
be required for the application. To complete the calculation, some basic information is
required. Remember to use the worst-case values to ensure that the braking power is
not underestimated. For example, use the maximum possible motor speed, maximum
inertia, minimum deceleration time and minimum cycle time that the application might
encounter.
Requirement
a) Initial motor speed, before deceleration
begins, in radians per second. 

Multiply RPM by 0.1047 to give radians
per second.
b) Final motor speed after deceleration is
complete, in radians per second. 

Multiply RPM by 0.1047 to get radians
per second. This value will be zero if the
load is going to be stopped.
c) The deceleration time from initial speed
to final speed, in seconds.
d) The total cycle time (i.e. how frequently
the process is repeated), in seconds.
e) Total inertia.

This is the total inertia seen by the drive,
accounting for motor inertia, load inertia
and gearing. Use the Mint WorkBench
Autotune tool to tune the motor, with the
load attached, to determine the value.
This will be displayed in kg·m
Autotune tool. If you already know the
motor inertia (from the motor spec.) and
the load inertia (by calculation) insert the

total here.

2
Multiply kg·cm
2
Multiply lb-ft by 0.04214 to give kg·m
2
Multiply lb-in-s
2
in the
by 0.0001 to give kg·m
by 0.113 to give kg·m
Enter value here
Initial motor speed, U = _________ rad/s
Final motor speed, V = _________ rad/s
Decel time, D
Cycle time, C
Total inertia, J
2
.
2
.
2
.
Resistor braking 173
= _________ s
= _________ s
2
= ________ kg·m