MTS Series 505G2 SilentFlo Hydraulic Power Unit Model 505G2-30 - Manual (Page 18)

Model 505G2.20 - 505G2.30 SilentFlo™ HPU 18
505.20/.30 HPU Functional Description
Introduction
The effective operating range of the auto-cooling circuit is between system
pressures of 14 MPa (2000 psi) to 21 MPa (3000 psi). In order for the auto-
cooling valve to function properly, it must be re-adjusted anytime the output
pressure is changed and operation of the HPU at the new pressure is to be longer
than 10 minutes.
Note If the test condition requires a maximum pressure level less than 14 MPa
(2000 psi), consult MTS.
Electrical Control
The HPU can be controlled locally using the front panel controls, or remotely
through a controller via the J1 connector. The controls included in the electrical
enclosure include the following:
• A start/low/high switch ensures that the system starts in low pressure, and
permits quick selection of low or high pressure. Wye-delta starting reduces
the initial current rush to the motor when electrical service to the HPU is
turned on.
• Thermal overloads protect the HPU from excessive current draw.
• A latchable Stop button prevents inadvertent starts.
• Interlocks protect the HPU against low hydraulic fluid level,
overtemperature, and dirty filters.
• Front panel indicators provide a quick indication on the unit’s condition.
These include power on, low level, overtemperature, and dirty filter lights.
– A Reset button brings the unit back into operation after a fault has been
detected and corrected.
– A dirty filter signal will not shut the unit down, but it will prevent the
unit from starting.
• An hour meter is provided to help you determine maintenance intervals.
The power disconnect switch on the door of the electrical enclosure ensures that
power is removed whenever the door is opened. It is a lockable, main-disconnect
switch.