Siemens SINAMICS S120 Configuration Manual page 82

Motor components
6.3 Holding brake (option)
Figure 6-5
Important information and instructions when installing the connecting cable
The brake connecting cable is included in the power cable. The insulation between the
power and brake connection is dimensioned for basic insulation (VDE 600 V/1000 V UL).
The relay K1, located between the coil and contact, must also have basic insulation in order
to protect the internal logic voltage (PELV=Protective Extra Low Voltage). The PELV supply
may not be used to supply the holding brake (refer to Fig. "Recommended circuit for the
external power supply with protective circuit").
Determining the minimum voltage
The minimum voltage of 24 VDC -10% must be available at the connector on the motor side
in order to guarantee that the brake reliably opens. If the maximum voltage of 24 VDC +10%
is exceeded, then the brake could re-close. The voltage drop along the brake feeder cable
must be taken into consideration.
The voltage drop ∆U for copper cables can be approximately calculated as follows:
∆U [V] = 0.042 ∙ (l/q) ∙ I
82
Terminology (time) for holding operation
Brake
Configuration Manual, (PFK7S), Edition 12.2006, 6SN1197-0AD16-0BP1
l = Cable length [m]
q = Brake core cross section [mm
I = DC current of brake [A]
Brake
]
2
Synchronous Motors 1FK7