Lenze 530 series User Manual

28
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6.2 Electrodynamic braking
If the field is excited, the induced armature current is used for braking the
motor. Before connecting the brake resistor, the controller is inhibited. The
timer relay must be set such that the braking contactor only opens after the
motor has stopped.
Dimensioning of the brake resistor R
B
Neglecting the armature feedback for a required initial braking torque M
Ba
, the
initial braking current I
ABa
results in:
II
ABa AN
=⋅
M
M
Ba
N
I
AN
= Rated armature current
M
N
= Rated torque
M
Ba
= Initial braking torque
The braking resistor R
B
is calculated as follows:
R
B
=
⋅U
I
Aa A
ABa
η
2
U
Aa
= Armature voltage in the motor mode
I
ABa
= Initial braking current
η
A
= Armature efficiency
η
π
A
AA
Mn
UI
=
⋅⋅
⋅
2
U
A
= Armature voltage
I
A
= Armature current
M = Torque
n = Speed
The size of the brake resistor depends on the braking energy of the drive and
the number of brakings. The braking current should not be more than twice the
rated armature current and should not exceed the maximum starting current.

Lenze 530 series Specifications

General

Brand	Lenze
Model	530 series
Category	Controller
Language	English