Configuration
3.4 Interconnection
Hydraulic Drive
System Manual, 04/2015, 6SL3097-4BA00-0BP1
51
26.5 V power supply for the hydraulics
Requirements
Note
Only use power supplies that provide SELV (Safety Extra Low Voltage) or PELV (Protective
Extra Low Voltage) output voltages for all connections and terminals of the electronics
modules.
This power supply is used to switch and supply the following hydraulic components via the
closed-loop control:
● Servo solenoid valves
● Pressure sensors
● Shutoff valves
● Valve spool sensors of shutoff valves
Primary-clocked regulated power supplies must be used as a result of the specified voltage
tolerance and the high currents.
Approx. 0.2 A intrinsic current demand + external loads (servo solenoid valve, shutoff valve +
valve spool sensor, pressure sensors)
● Other requirements placed on the external 26.5 V supply:
– Voltage range 26.5 V ±2 % (26.0 V ... 27.0 V)
– Ripple 265 mVpp
– No interruptions/dips
Brief interruptions/dips on the 26.5 V power supply are also not permitted, as
otherwise an internal undervoltage will be detected resulting in shutdown.
Device damage due to overvoltage
For overvoltages exceeding 35 V (even briefly) there is the risk that the internal overvoltage
protection will respond, the internal fuse ruptures – and therefore the module becomes
defective.
• Make sure that you take into account the specified voltage limits.
The voltage tolerance is required at the module terminals: At higher currents, significant
voltage drops can occur across the P and M feeder cables. This is the reason that the cables
must be kept as short as possible and very large cross-sections must be used. Alternatively,
a power supply with remote sense terminals to compensate the voltage drop along the
feeder cables can be used.
Just a few 100 mV below the 26.0 V, the internal monitoring function identifies an
undervoltage condition; the shutoff valves represent an upper limit as they can be thermally
overloaded for higher voltages.
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