Brake Resistors; Brake Resistor Selection - ABB ACS350 User Manual

302

Brake resistors

ACS350 drives have an internal brake chopper as standard equipment. The brake
resistor is selected using the table and equations presented in this section.

Brake resistor selection

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
• The resistor must be able to dissipate energy E
Equations for selecting the resistor:
Eq. 1.
Eq. 2.
Eq. 3.
For conversion, use 1 HP = 746 W.
where
R
P
Rmax
P
Rave
E
Rpulse
t
on
T
Technical data
BRmax
Rpulse
drive type.
cycle T.
U = 200...240 V:
N
U = 380...415 V: R =
N
U = 415...480 V: R =
N
E = P · t
Rpulse Rmax
t
P = P ·
Rave Rmax
= selected brake resistor value (ohm)
= maximum power during the braking cycle (W)
= average power during the braking cycle (W)
= energy conducted into the resistor during a single braking pulse (J)
= length of the braking pulse (s)
= length of the braking cycle (s).
given in the table on page
with Equation 2.
and R
min
150000 t
R =
P
Rmax
450000
P
Rmax
615000
P
Rmax
on
on
T
for the application. P
Rmax
303 for the used drive
given in the table for the used
max
during the braking
Rpulse
on
T
Rmax
.
Rmax
P
Rmax
P
Rave