General information
2.5 Accessories
SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 04/2019, A5E36037884-007
49
2.5.4
External 24 V DC power supply
A 24 VDC power supply is needed to supply the V90 servo drive. Refer to the table below to
select the power supply:
Parameter
Description
Rated voltage (V)
24 (-15% to +20%)
1)
Maximum current (A)
When using a motor without a brake: 1.6 A
When using a motor with a brake: 1.6 A + motor holding brake rated cur-
rent (See Section "Technical data - servo motors (Page 68)")
Ripple caused by the
rectifier
≤ 5%
Safety insulation class
PELV
1)
When using a motor with a brake, the minimum voltage of 24 V DC -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 ΔU for copper cables can
be approximately calculated as follows:
ΔU [V] = 0.042 Ω·mm
2
/m ∙ (l/q) ∙ I
Brake
Where: l = Cable length [m], q = Brake cable cross section [mm
2
], I
Brake
= DC current of brake [A]
Note
Make sure that you use different 24 V DC power supplies for the drive and for the inductive
loads such as relays or solenoid valves; otherwise, the drive may not work properly.
Note
The max. length of the cable used to connect the 24 V DC power supply to the drive is 10 m.
