Brake pow-
er (KW)
Brake chopper
type code
Number of
brake
choppers
Brake resistence(Ω) Power of brake resis-
tor(KW)
Number of
paralleled
brake re-
sistors
Recom-
mended
value
Min. value
Recom-
mended
value
Min. value
75
FEAE07.1-EA2-
NNNN
1
13.6
≥5
9.60
≥9
2
90
1
20
≥5
6.00
≥10
3
Tab. 4-3: Type selection of brake resistor
●
The recommended resistance of the brake resistor is 100 % brak-
ing torque, selected according to necessity. If the actually needed
torque is not 100 %, the resistance of the brake resistor in the ta-
ble should be adjusted in inverse proportion, i.e. how much the
braking torque increases based on 100 %, the resistance of the
brake resistor should decrease by the same amount, vice versa.
●
When selecting brake resistor R
b
, make sure the current I
c
which
flows through the resistor is less than the current output ability of
the brake chopper. The current I
c
through the brake resistor can
be calculated by formula I
c
= U
d
/ R
b
, in which U
d
is the braking
operating voltage of brake chopper.
●
After the adjustment of the resistance of brake resistor, the power
of brake resistor should be also adjusted appropriately. The pow-
er can be calculated by formula P
max
= U
d
2
/ R
b
. According to the
actual working condition, the braking ratio ED % can be selected
to reduce the power of brake resistor reasonably for intermittent
braking load. The power of brake resistor can be calculated by for-
mula P
R
= k × P
max
× ED %, in which 'k' is the derating coefficient
of brake resistor. The selection of the braking torque should be in
general smaller than 150 % of the rated motor torque, or consult
the technical support for more information.
●
When ED>10 %, the master / slave control mode is recommended
(see
chapter 9.2.2 "Master / Slave Control Mode" on page 48
),
or consult the technical support.
Bosch Rexroth AG
Brake Chopper Overview
Brake Chopper
20/65
DOK-RCON03-EFC*BRAKE**-IT01-EN-P
