Truck & Off-Highway Engineering - June 2024 - 23

TECHNICAL INNOVATIONS
droop of the engine or reduction in shaft
speed of the electric motor, and then
makes an adjustment to compensate.
Proactive ETL control systems are preprogrammed
with the actual torque or
power curve of the prime mover. As
speed or other conditions vary, ETL proactively
sets itself for that condition.
The benefit of proactive ETL is fasterresponding
control. In fact, OEMs can
be more aggressive with oversizing the
pump because it's able to capture more
of the operating envelope than a slower-reacting
solution. Adding more flow
within the same boundaries of the duty
cycle is beneficial because it enables
the machine to move faster or undertake
more simultaneous movements,
thereby boosting productivity.
Mechanical torque controls are also
available. These provide some of the
power management functionality that
ETL provides but come with compromises.
For example, there are certain
performance areas of the map that
these solutions are not able to cover.
Testing reveals redundancies
MPG tested several of the torque control
solutions on the market. " We tried
a hydraulic torque-controlled pump,
but it was difficult to make the torquelimiting
adjustment manually, " Alver
said. " Some torque-controlled pumps
did not allow adjustments other than
Replacing a standard pressure-compensated load-sensing pump with an electronic torque-limiting
pump eliminated the electric-motor stalling problem MPG experienced.
the factory setting. "
MPG then tested the Danfoss Series
45 pump with electronic torque limiting.
The pump proactively and automatically
maximizes system pressure in
milliseconds for the available torque
while preventing stalls. The speedtorque
graph of the engine or motor to
which the pump is connected is loaded
into the controller of the ETL system.
The PLUS+1 GUIDE software modulates
the pump's control for a given engine
speed according to the available torque.
Based on system requirements and
sizing, a 130cc Series 45 ETL pump and
an MC012-112 controller were selected.
Danfoss provided a prototype and
helped MPG carry out system testing.
MPG engineers determined that they
didn't need to upsize the motor and
that they could eliminate several components
from the system.
Alver explained: " We used a Series
45 ETL pump, and we eliminated the
electric-motor stalling problem. We did
not need to use a soft starter and inverter,
and we could easily adjust the
desired optimum torque value thanks to
the PLUS+1 software. "
The Danfoss Series 45 ETL pump also delivered
efficiency improvements of 15% compared to a
standard PCLS pump.
TRUCK & OFF-HIGHWAY ENGINEERING
One pump fits all
For MPG's truck-mounted crane, the
Danfoss Series 45 ETL pump increased
productivity by eliminating stalling, reduced
costs by eliminating the need for
a larger motor and driver as well as other
components, and delivered efficiency
improvements of 15% in comparison to
a standard PCLS pump.
" With the machines we produce with
ETL pumps, our customers can push
their limits without any problems, and
we can offer quick and easy solutions to
any system change requests thanks to
PLUS+1 software. The key advantage
here is flexibility and ease of implementation, "
Alver said.
The Danfoss Series 45 ETL pump can
be applied in any existing PCLS system
with or without existing power management
functionality. It can be a drop-in
replacement for any mechanical torque
control pump. Since machine adjustments
are made with software, there is no need
to change pump hardware to adjust the
torque-limiting settings. One ETL pump
can cover the torque range of almost any
engine or electric motor, eliminating the
need to carry multiple part numbers for
different torque settings.
" Thanks to the Series 45 ETL pump,
we are able to meet the different demands
of our customers, not only electrification, "
Alver added. " For example,
some of our customers want to use an
external diesel engine for the crane
structure, and often the performance
and torque curves of these engines can
be different. [But] we can use our diesel
engine with the highest performance by
determining our torque limits via
PLUS+1 for each diesel engine. "
Gökhan Avci, senior account manager, and
Vince Ewald, Open Circuit Pumps portfolio
manager, Danfoss Power Solutions, wrote this
article for Truck & Off-Highway Engineering.
June 2024 23
FROM TOP: MPG; DANFOSS

Truck & Off-Highway Engineering - June 2024

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