MTS Series 505G2 SilentFlo Hydraulic Power Unit Model 505G2-11 - Manual (Page 50)

Model 505G2.07/.11 SilentFlo™ HPU 50
Low/High Pressure Functionality
5. If necessary, repeat steps 2 and 3 until the Auto-Cooling Valve is stable and
the HPU cools properly.
6. After the final adjustment, hold the HPU Output Pressure Control to prevent
it from moving while tightening the nut to secure the setting.
7. Verify the output pressure remained at the desired level and the nut to secure
the setting.
A. Hold the Auto-Cooling Valve stem to prevent it from turning while
tightening the nut.
Low/High Pressure Functionality
This section clarifies the low and high pressure functionality of the HPU. There
are certain cases where it is advantageous to use the HPU in low pressure versus
high pressure. Low/High functionality is illustrated in the block diagram below:
Low pressure
Series 505 HPUs are started in low pressure to reduce the amount of current
inrush at motor startup. A solenoid valve that opens a direct flow path to the
return line commands the pressure setting. Because this direct path offers little
resistance to the full flow, minimal system pressure is developed (low pressure).
Low pressure operation of a Series 505 HPU provides several useful functions
when high pressure is not required by the external system.
System commissioning
Best practices for system commissioning include flushing the hard line and
related equipment. This process “conditions” the hydraulic fluid to a cleanliness
level that supports high performance servovalve systems. (Refer to the Hydraulic
Fluid Care Guide (part number 050-000-536) for information on fluid
cleanliness.)
High Pressure Flow to
External System Return Flow from System
Auto-cooling
HPU Manifold
Low Pressure
Flow
Heat Exchanger Filter
Reservoir