2. Calculate resistance
R
with Equation 1.
3. Calculate energy
E
Rpulse
with Equation 2.
4. Select the resistor so that the following conditions are met:
• The rated power of the resistor must be greater than or equal to
P
BRcont
.
• Resistance R must be between
R
min
and
R
max
given in the table for the used
drive type.
• The resistor must be able to dissipate energy
E
Rpulse
during the braking
cycle
T
.
Equations for selecting the resistor:
160 ()
, R0…R3
R0…R3 :
1.
P
Rmax
P
Rmax
P
BRmax
,
161
2. 1
R
3. 2
E
Rpulse
4.
:
•
P
Rmax
•
R
R
R
•
E
Rpulse
T
:
R
= (ohm)
:
R
min
<
R
<
R
mxx
.
P
Rmax
=
(W)
P
Rave
=
(W)
E
Rpulse
=
(J) (J)
t
on
=
(s)
T
=
(s)
t
on
P
Rmax
P
Rave
T
450000
P
Rmax
U
N
=
615000
P
Rmax
U
N
=
R
P
Rmax
E
Rpulse
=
t
on
P
Rmax
P
Rave
=
t
on
T
R
Equation 1
(supply voltage 380...415 V)
Equation 2
For conversion, use 1
hp = 746 W
Equation 3
Calculated brake resistor value (ohm). Make sure that:
Maximum power during the braking cycle (W)P
Rmax
Average power during the braking cycle (W)P
Rave
Energy conducted into the resistor during a single braking pulse (J)E
RPulse
Length of the braking pulse (s)
Length of the braking cycle (s)
The table below shows reference resistor types for the maximum braking power.
182 Resistor braking
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