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Newage PRM
Marine Power Take-Offs |
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PRM
Power Take-Offs |
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PRM Power Take-Offs For:
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Modern boats,
not just fishing craft and workboats but
also pleasure craft, increasingly demand
auxiliary power for driving on-board
machinery such as winches, pumps or
compressors. The traditional method of
meeting these requirements has been to take
an auxiliary drive from the front of the
main propulsion engine, which involves
expensive and space consuming vee-belt
installations.
PRM500, PRM750 and PRM1000 marine
transmissions now offer you compact, low
cost and efficient alternatives: a choice of
clutched or direct drive power take-off
units which bolt directly to the rear face
of the gearbox, either as factory fitted
options or as assemblies for retro-fitting
to existing gearbox installations. Both
versions are specifically designed to drive
hydraulic pumps, whether of the gear, vane
or piston type; they are not intended to be
adapted for driving an outrigger pulley. |
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The
PRM clutched power take-off is available on
the PRM1000 marine gearbox; its clutch is of
the multi-disc type, similar in design to
those used in the main gearbox, and is
suitable for remote control from the bridge
or wheel house using a proprietary
cable-operated remote control. |
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Operation -
Clutched Power Take-Off |
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When
the operating lever is moved to the engaged
position, oil pressure is taken from the
gearbox control valve via the 1/8" BSP
tapping provided for the oil pressure gauge;
this causes the power take-off clutch to be
engaged, thus providing drive to the pump.
When the lever is in the disengaged position
there is no hydraulic pressure on the
clutch, which therefore remains disengaged;
consequently there is no drive to the pump.
Lubrication of the power take-off system is
provided by oil directed at low pressure
from the return line from the oil cooler. |
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Direct Drive
Power Take-Off |
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Available on the PRM500 and PRM 750 the
direct drive power take-off is driven
directly from the gearbox input shaft;
consequently it will operate at all times
when the engine is running, and since there
is no clutch for disengagement of the
hydraulic pump, provision must be made in
the auxiliary hydraulics circuits for
pressure by-pass to the reservoir when power
to the pump is not required. A pair of 1:1
ratio gears, providing sufficient offset
between the gearbox output shaft and the
centreline of the power take-off to ensure
there is sufficient clearance between the
hydraulic pump and propeller shaft coupling. |
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All
power take-offs are specifically designed
for driving hydraulic pumps to SAE J744C
series 'B' specification with splined input
shaft and either two-bolt or four-bolt
fixing. The maximum power which can be
transmitted is 22 KW (29.5 bhp) per 1000
rev/min engine speed; this equates to a
torque of 209 Nm (155 Ibf.ft. - 21.33 kgm.).
For PRM1000 the clutched power take-off
gives pump rotation the same as the engine,
where as the direct drive power take-off for
the PRM500 and PRM750 will give opposite
rotation. Power to the pump is not affected
by the normal use of the gearbox for
propulsion duties. All ancillary power
circuits driven by PRM power take-offs
should be designed in accordance with the
recommendations of the hydraulic equipment
manufacturer, and should be properly
safeguarded against overloading. |
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PRM
power take-off units fit on the rear face of
the main gearcase and are driven by the
input shaft; consequently they can be
operated at all times whilst the engine is
running, The power take-off replaces the end
cover which is normally fitted and performs
the functions of the end cover by sealing
the gearbox against loss of oil and
correctly positions the input shaft rear
bearing. Power take-off units also provide
the link between the gearbox and the
hydraulic pump. |
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Back to
Newage PRM Marine Transmissions |
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