LEYBOLD VARODRY CD200, Operating Instructions Manual

Page: 17 / 52

Figure 5. Electrical connection
After connecting the motor and after every time you alter the wiring, check
the direction of rotation. To do so, briefly switch on the motor and make sure
that the pump fan rotates in counter-clockwise direction. If not, interchange
two phases of the connection.
An arrow (sticker) indicating the correct direction of rotation is placed on the
drive cover. To avoid damage to the pump or the vacuum system make sure
that the inlet of the pump is not connected to a closed vacuum system
when doing this test. Running the pump at full speed in the wrong direction
of rotation will generate pressures up to 4.5 bar (g) at the inlet port, if not
vented to atmosphere.
Figure 6. Arrow - direction of rotation
5.6 Optional VFD use
If desired the pumps can be operated via an external variable frequency
drive (VFD). However it is not allowed to run the pump with more than the
nominal speed. A range of suitable VFDs is available as accessories. Please
consult us if other types of VFDs shall be used. The permissible motor
speed defined in the
Technical data on page 10 must be obeyed.
Please note that the pump performance and power consumption is not a
linear function of motor speed.
5.7 Purge gas/Gas ballast connection (optional)
The pump has a gas ballast system and an optional seal-purge system. It
consists of three components.
1. Gas ballast
The pump is equipped with a gas ballast which feeds ambient air into
the pump to dilute condensable vapours and keep the partial pressure
below the condensation level. The pump water vapour tolerance is 60
mbar. A high vapour tolerance will reduce the vacuum performance of
the pump. If the presence of condensable vapours in the pumped
gases can be ruled out the gas ballast can be closed. Using the gas
ballast will improve the vapour handling but reduce the vacuum
performance of the pump.
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300766038_002_C3 - 09/2021 - © Leybold
Installation