Design - 8200 and 9300 vector

Braking

Options

Braking with brake unit Selecting brake resistors If a motor is braked quickly by the frequency inverter, themotor will operate in generative mode and feed back energy to the frequency inverter. The DC bus voltage of the frequency inverter increases. If the voltage is too high, the frequency inverter will lock the power stages and themotor will coast to a stop. By using a brake unitcomprising a brake module with integrated resistor or brake chopper with external resistor, the feedback energy can be dissipated via the brake resistor and converted intoheat. The drive can be braked under controlled conditions. Brake resistors are selected according to the continuousenergy loss exhibited and the energy to be braked. The following formula is used to calculate the rated power of the brake resistors:The maximum kinetic energy to be suppressed iscalculated on the basis of the peak brake power and the maximum duty time of the brake chopper.W Feedback mode A supply and feedback module can also be used as an alternative, in particular on multi-axis and interconnected drives. These components help to reduce energyconsumption and costs.
Br kin N â‰¥t t x P
zyk max ; P
max = 1 W 2 t
Br max = P
max ·t
0max P
max : Brake power during brakingt
Br : Braking timet
cyc : Time between two braking cyclesW
kin : Kinetic energy to be brakedt
0max : Maximum duty time of brake chopperAs the frequency change is also applied in the brakingphase via the setpoint integrator on the inverter, the “Tif”value set on the inverter can also be used for the braking time t
Br . P 80

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