8.9.3
Dual-Frequency Braking Limitations
Limitations of DFB
The drive output current plus the braking current must not exceed the current capability of the
cells in the drive. Hence the braking torque is limited in the drive, it is greatest at slow speed and
smallest at high speed. The typical braking torque that can be expected with DFB is illustrated
below.
3HUFHQWRI5DWHG6SHHG
3H
UF
HQ
WR
I5
DW
HG
7
RU
TX
H
,
P
D[
Figure 8-5
Braking torque with DFB for a typical motor
With high efficiency and inverter duty motors, the braking torque that can be achieved with DFB
is lower than the values shown in the figure above.
Contact Siemens customer service with the motor-related data listed below to determine the
braking torque capability with a higher efficiency motor. Information on critical frequencies will
allow a selection for the torque pulsation frequency.
Table 8-1
Motor related data
Rated HP
Rated Voltage
Rated frequency
Full-load speed
Half-load efficiency
Full-load efficiency
Half-load power factor
Full-load power factor
Locked-rotor torque
Locked-rotor current
Pull-out torque
Critical frequencies of the mechanical system
Advanced Operating Functions
8.9 Dual-Frequency Braking
Control Manual
Operating Manual, A5E50491925A
247
Summary of Contents for SINAMICS PERFECT HARMONY GH180
Page 2: ......
Page 22: ...Table of contents NXGPro Control Manual 20 Operating Manual A5E50491925A ...
Page 24: ...Security NXGPro Control Manual 22 Operating Manual A5E50491925A ...
Page 504: ...NEMA Table NXGPro Control Manual 502 Operating Manual A5E50491925A ...
Page 517: ...Index D NXGPro Control Manual Operating Manual A5E50491925A 515 ...
Page 518: ...Index NXGPro Control Manual 516 Operating Manual A5E50491925A ...
Page 530: ...Glossary NXGPro Control Manual 528 Operating Manual A5E50491925A ...
Page 537: ......