Dynamic Braking; Sizing The Braking Resistor - WEG CFW-11 Series User Manual

Installation and Connection

3.2.3.2 Dynamic Braking

NOTE!
All frame sizes B and C models do have internal braking IGBT. Models of frame sizes D and E with
the codification CFW11...O...NB... and all models of frame sizes F, G and H do not have internal
braking IGBT.
NOTE!
For dynamic braking with frame sizes F, G and H models use external braking module (see
Use of External Dynamic Braking Module DBW03 and DBW04 on page
to Figure 3.31 on page
The braking torque that can be obtained from the frequency inverter without braking resistors varies from 10 %
to 35 % of the motor rated torque.
3
Braking resistors shall be used to obtain higher braking torques. In this case, the energy regenerated in excess
is dissipated in a resistor mounted externally to the inverter.
This type of braking is used in cases where short deceleration times are desired or when high inertia loads are
driven.
The "Optimal Braking" feature may be used with the vector control mode, which eliminates in most cases the
need of an external braking resistor.
NOTE!
Set P0151 and P0185 to their maximum values (1000 V for power supply voltages from 500 to 600 V;
1200 V for power supply voltage from 660 to 690 V) when using dynamic braking.

3.2.3.2.1 Sizing the Braking Resistor

The following application data shall be considered for the adequate sizing of the braking resistor:
- Desired deceleration time.
- Load inertia.
- Braking duty cycle.
In any case, the effective current value and the maximum braking current value presented in
3-29 shall be respected.
The maximum braking current defines the minimum braking resistor value in ohms.
3-38 | CFW-11
3-39.
Item 7.2.1
7-4). For installation refer
Table 3.8 on page