Siemens SINAMICS G110D, Руководство по эксплуатации

Страница: 132 / 224

Functions
6.9 Technological functions
SINAMICS G110D
132
Operating Instructions, 07/2016, FW V3.63, A5E36768472B AB
6.9.2.2 DC braking
Application areas for DC braking
DC braking is typically used for applications in which the motor is normally operated at a
constant speed and is only braked down to standstill in longer time intervals, e.g. centrifuges,
saws, grinding machines and conveyor belts.
Operating characteristics of DC braking
Image 6-9 DC braking after an OFF1 or OFF3 command
DC braking after an OFF1 or OFF3 command has the following timing sequence:
1.
Initially, the motor speed is reduced along the down ramp of the ramp-function generator
until an adjustable speed threshold is reached.
2. Once the motor speed reaches this threshold, the inverter interrupts the braking operation
using an internal OFF2 command until the motor is de-magnetized.
3. The inverter then starts the actual DC braking by allowing a DC current to flow through
the motor. The magnitude and duration of the DC current can be set.
CAUTION
For DC braking, the kinetic energy of the motor and motor load is partially converted into
thermal energy. The motor can overheat if braking lasts too long or the drive must be
braked too frequently.