MTS Model 512-01 Hydraulic Power Unit - Manual (Page 6)

Model 512.01 Hydraulic Power Unit 6 Introduction
Functional Description
The hydraulic power unit (HPU) is the mechanical source of high-pressure
hydraulic fluid required to operate the hydraulic components of a test
system. See
“Component Identification” on page 8 for more information
about the components described in this section.
Pump motor
A motor drives a hydraulic pump which draws hydraulic fluid from a
reservoir and pressurizes it to 6.9 MPa (1000 psi). The pressurized fluid is
made available to the hydraulic components in your test system.
Pressure
The HPU pressure output is adjusted with a pressure reducing valve which
is factory set to 6.9 MPa (1000 psi). If the output pressure exceeds the
pressure setting, a pressure relief valve shunts the excessive pressure to the
hydraulic return line. The output pressure can be set to 6.9 MPa (1000 psi)
or less.
Filtering
The filtration system protects against silting by cleaning the hydraulic fluid
to an ISO particle count of 14/10 or better. The filter change gage indicates
when the filter needs to be changed.
A suction strainer protects the pump from larger particles when the fluid is
pumped from the reservoir. It is located in the bottom of the hydraulic fluid
reservoir.
Heat exchanger
Hydraulic fluid temperature is maintained with a heat exchanger that cools
the fluid. The heat exchanger helps keep the temperature of the hydraulic
fluid between 43–52°C (109–126°F). The temperature of the fluid is
monitored by an overtemperature switch. If the fluid temperature exceeds
55ºC (130ºF), a switch opens and shuts down the HPU. The system cannot
be restarted until the fluid cools.
The air-cooled heat exchanger cools the hydraulic fluid as it passes
through a radiator. A fan blows air through the radiator to transfer heat
from the radiator to the air.
Electronics
The HPU has basic controls to turn it on and off. The HPU includes a
connector to add a remote
Emergency Stop switch. The HPU requires an
Emergency Stop switch or a jumper plug to be installed in order to run.