ABB MicroFlex e150 User Manual

142 Technical data
 Braking energy
The braking energy to be dissipated, E, is the difference between the initial energy in
the system (before deceleration begins) and the final energy in the system (after
deceleration has finished). If the system is brought to rest then the final energy is
zero.
The energy of a rotating object is given by the formula:
where E is energy, J is the moment of inertia, and ω is the angular velocity.
The braking energy, which is the difference between the initial energy and the final
energy, is therefore:
= ________________ J (joules)
Calculate E using the values for J, U and V entered in the table on page 141. If E is
less than the drive's braking capacity (see Braking capacity on page 140), a brake
resistor is not required.
If E is greater than the drive's braking capacity, then continue to the next section to
calculate the braking and average power dissipation.
 Braking power and average power
The braking power P
r
is the rate at which the braking energy is dissipated. This rate is
defined by the deceleration period, D. The shorter the deceleration period, the greater
the braking power.
= ________________ W (watts)
The resistors shown in the following table can withstand brief overloads, but the
average power dissipation, P
av
, must not exceed the stated power rating. The
average power dissipation is determined by the proportion of the application cycle
time, C, spent braking. The greater the proportion of time spent braking, the greater
the average power dissipation.
= ________________ W (watts)
E
= — × JîȦ
2
1
2
— ×
J × U
2
E
=–
1
2
— × J × V
2
1
2
()()
— × J × (U
2
– V
2
)=
1
2
P
r
= —
E
D
P
av
= P
r
× —
D
C

ABB MicroFlex e150 Specifications

General

Brand	ABB
Model	MicroFlex e150
Category	Control Unit
Language	English