7
The Three Phase Current Motor Circuit
The three phase motor winding consists of three identical
coils.
Delta Connection
The three coils are connected in series with the connection
point connected to the mains. The voltage of each coil is the
same as the mains voltage whereas the mains current is the
cube root of the coil current. Delta connections are denoted
by the symbol
∆∆
.
The voltage between the mains supply lines is called mains
voltage. The mains current is the current which flows in the
supply lines.
Star Connection
The ends of the three coils are connected at the star center.
The terminal voltage is the cube root of the coil voltage; the
mains and the coil current are the same. Star connections are
denoted by the symbol
Y.
A star connection three phase motor for 400 V mains voltage
has a coil voltage of 230 V.
W2
U1
L1
V2
V1
W1
U2
L3
L2
W2
U2
V2
U1
V1
W1
L1 L2
L3
W2
U1
L1
V2
V1
W1
U2
L3
L2
W2
U2
V2
U1
V1
W1
L1 L2
L3
Motor coil and connecting plate of Delta Connection
Motor coil and connecting plate of Star Connection
Rotation Speed and Operating Hours Monitor RCI 002
3.6. Monitoring Connection
The Rotary Vane Pumps UNO/ DUO 120 A have been designed
so that they can be connected to a Rotation Speed and
Operating Hours Monitor RCI 002, which is connected at
connecting socket 45. For the operation and application of
this device please refer to the relevant operations
instructions.
Important: The instructions in
4.1.2
must be
observed when working with synthetic
operating medium F5.
CAUTION
3.7. Special Models
Helium Tight and Corrosive Gas Models
Helium tight and corrosive gas models are becoming
increasingly important.
– Helium tight models are distinguished by their high level
tightness to the atmosphere. Corrosive gas models are
manufactured with special materials.
– There is a different high vacuum safety valve control.
– The rotor shaft of both versions is sealed with an
additional radial shaft seal. The cavity between the radial
shaft seals 118 and 133 is filled with operating medium and
is supplied by the oiler 136.
– If the gas ballast valve 2 is not available, the opening
should be closed with the locking screw 169 or a special
gas ballast valve with dosing device and hose connection
for flushing gas is available (on request).
– Helium tight models are operated, as standard, with opera-
ting medium P3 and the corrosive gas version with synthe-
tic operating medium F5, also as standard.
