3.1.2 Supply air pressure
The required supply air pressure depends
on the bench range and the actuators fail-
safe action. The bench range is registered
on the nameplate either as spring range or
signal pressure range.
Actuator stem extends:
required supply air pressure =
upper bench range value + 0.2 bar
at least 1.4 bar.
Actuator stem retracts:
for tight-closing valves, the signal pressure
p
st max
is roughly estimated as follows:
pst
max
= F +
d
2
⋅
π
⋅
Δ
p
4
⋅
A
[bar]
d
= Seat diameter [cm]
Δ
p = Differential pressure p
p
[bar]
A
= Actuator area [cm
]
F
= Upper bench range value of the actuator [bar]
If there are no specifications, calculate as
follows:
required supply air pressure =
upper bench range value + 1 bar
3.2 Electrical connections
As far as the electrical installation of
the device is concerned, the relevant
national regulations governing the
installation of electrical equipment
and the national accident prevention
regulations of the country of destina-
tion must be adhered to.
In Germany, these are the VDE regu-
lations and accident prevention regu-
lations of the employers liability in-
surance.
For installation in hazardous areas,
the following standards apply: EN
60079-14: 1997; VDE 0165 Part
1/8.98 "Electrical apparatus for ex-
plosive gas areas" and EN 50281-1-
2: VDE 0165 Part 2/11.99 "Electri-
cal apparatus for use in the
presence of combustible dust".
For intrinsically safe electrical ap-
paratus that are certified according
to the Directive 79/196/EEC, the
data specified in the certificate of
conformity apply for connection of
intrinsically safe circuits.
For intrinsically safe electrical ap-
paratus that are certified according
to the Directive 94/9/EC, the data
specified in the EC type examination
certificate apply for connection of in-
trinsically safe circuits.
Note:
It is absolutely necessary to
keep to the terminal plan specified
in the certificate. Reversal of the elec-
trical connections may cause the ex-
plosion protection to be ineffective!
EB 8380-1 EN
29
Connections
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