Resistor Braking, Frames R0; Planning The Braking System - ABB ACS580-01 Hardware Manual

190 Resistor braking
Resistor braking, frames R0...R3


Planning the braking system

Selecting the brake resistor
Frames R0...R3 have an built-in brake chopper as standard equipment. The brake
resistor is selected using the table and equations presented in this section.
1. Determine the required maximum braking power P
must be smaller than P
type.
2. Calculate resistance R with Equation 1.
3. Calculate energy E
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
• Resistance R must be between R
drive type.
• The resistor must be able to dissipate energy E
cycle T.
Equations for selecting the resistor:
U = 400 V: R =
Eq. 1.
N
U = 480 V: R =
N
Eq. 2. E = P
Rpulse Rmax
Eq. 3. P = P
Rave Rmax
where
R = calculated brake resistor value (ohm). Make sure that: R
P = maximum power during the braking cycle (W)
Rmax
P = average power during the braking cycle (W)
Rave
E = energy conducted into the resistor during a single braking pulse (J)
Rpulse
t = length of the braking pulse (s)
on
T = length of the braking cycle (s).
given in the table on page
BRmax
with Equation 2.
Rpulse
450000
P
Rmax
615000
P
Rmax
·
t
on
t
on
·
T
Rmax
and R given in the table for the used
min max
Rpulse
t
on
T
For conversion, use 1 hp = 746 W.
min
for the application. P
191 for the used drive
Rmax
during the braking
P
P
< R < R .
mxx
Rmax
.
Rmax
Rave