Edwards RV3 - Performance Modes and Controls; Mode Selector

oil‑sealed, sliding‑vane vacuum pumps. The pump has NW25 inlet (4) and outlet (7)
ports, a gas‑ballast control (5) and a mode selector (11). When the pump is switched o,
an inlet‑valve seals the inlet and prevents the suck‑back of air and oil into the vacuum
system.
The RV3 and RV5 pumps have a retractable liing handle (3). The RV8 and the RV12
pumps are ed with a liing bracket for use with suitable liing equipment.
An oil‑pump delivers pressurised oil to the vacuum pumping mechanism in the RV
pump. The oil level and condion can be inspected in the oil‑box through a sight‑glass
(8). Two oil ller‑plugs (6) and an oil drain‑plug (9) are provided on the oil‑box.
The pump mechanism is driven directly by a single‑phase or three‑phase electric motor
through a exible motor‑coupling. The motor is totally enclosed and is cooled by the
motor cooling‑fan which directs air along the motor ns. The pumps are cooled by an
addional fan aached to the motor‑coupling.
Single‑phase motors are ed with an on/o switch (12) and a thermal overload device.
When the motor is too hot, the thermal overload device switches o the pump. The
thermal overload device has an automac reset; when the motor cools down, the device
resets and (unless suitable control equipment has been incorporated which must be
manually reset: see Connect the pump to the electrical supply on page 28 and Connect
the pump to the local electrical supply on page 30), the motor will restart.
As of the end of 2009 improved motors have been ed to RV pumps. These motors
benet from being ed with an aluminium terminal box and externally accessible
voltage change‑over switches. The introducon of these motors has resulted in the
range of motors covering all voltage and frequency condions being reduced from four
variants to two. All motors are interchangeable and pump performance is not aected.
The pump is mounted on a base plate on rubber feet (10). Details of suitable vibraon
isolators and other accessories are provided in Service and spares on page 50.
Refer to PFPE‑prepared RV pumps refer to PFPE-prepared RV pumps on page 56 for
addional informaon if the pump is PFPE‑prepared.
2.4 Performance modes and controls
The pump has two controls: the mode selector (11) and the gas‑ballast control (5). Six
possible combinaons of these controls allow for a wide choice of operang
characteriscs to opmise the performance of the pump for a given applicaon.
2.4.1 Mode selector
The mode selector has two posions, refer to How to use the pump controls on page 35
to select these posions. Throughout the rest of this manual, the following convenon is
used:
▪
The High Vacuum mode is specied by the S symbol.
▪
The High Throughput mode is specied by the S symbol.
With the mode selector set to High Vacuum mode S, pressurised oil is fed to the low
vacuum stage only. In this mode of operaon, the pump provides the best possible
ulmate vacuum.
03/2021 - ©Edwards Limited
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A65201880_AA - Introducon