MTS Series 505G2 SilentFlo Hydraulic Power Unit Model 505G2-180 - Manual (Page 22)

Run On Demand option
The run on demand (ROD) option will turn individual pumps on and off as needed to accommodate the
system’s demand for hydraulic fluid. The PLC monitors the fluid flow; when flow changes beyond preset limits
for a preset time, a pump will be turned on or off as needed.
The ROD option allows the HPU to turn individual pump motors on and off as your system flow demand
changes. A minimum flow reserve is maintained and pump usage is equalized by sequentially turning on
pumps starting with the pump with the least amount of run time, and turning the pumps off in reverse order.
The cycling of these pumps is controlled by a PLC that takes into account various system parameters such
as system hydraulic fluid flow (both real time and trends), the number of pumps currently running, and user
configurable on/off delay settings.
HPU Electrical Control
The HPU can be controlled locally using the front panel controls, or remotely through a controller. A PLC
(programmable logic controller) manages the electrical systems within the HPU. The electrical system includes
the following:
• A user interface panel that contains a touch screen to program preferences and operational settings. The
screens on the user interface panel provide quick indication of the unit’s condition, including motors status,
running time displays for each motor, hydraulic fluid level and temperature, and filter condition.
• Wye-delta starting reduces the initial current rush when the motor starters are engaged.
• Thermal overloads protect the individual HPU motors from excessive current draw.
• A latchable Emergency Stop button that shuts down the HPU and prevents inadvertent starts.
• Interlocks protect the HPU against low hydraulic fluid level, overtemperature, motor overload, and contactor
sequence.
• A Reset button brings the unit back into operation after a fault has been detected and corrected.
• A dirty filter signal is a warning only and will not shut the unit down, but will prevent the unit from starting.
• The power disconnect switch on the door of the main electrical enclosure ensures that power is removed
whenever the door is opened. This device is a TÜV-certified, lockable, main-disconnect switch.
Note:
The electrical schematics for the HPU are located on the following pages. The difference between
the Model 505.60/.90 and Model 505.120-180 is the number of pump assemblies.
22 Series 505G2 SilentFlo™ Hydraulic Power Unit Product Information
Introduction