ML7420A/ML7425A,B
EN0B-0624GE02R0399
2
Wiring
Wiring terminals
1.5mm
2
Cable entry
PG13.5. Two additional knock
outsPG11 andPG13.5 for
auxiliary switch and
potentiometer accessories
Weight
non spring return type 1.3kg
spring return type
2.4kg
Material
Cover
ABS-FR
Base
glass fibre reinforced plastic
Yoke
aluminium diecast
Model Number
ML7420A3006
ML7420A3014
ML7425A3005
ML7425B3004
SupplyVoltage
24Vac +/-15% 50/60Hz
Power Consumption
5VA
7VA
12VA
Signal Input 0(2)Vdc
Actuator stem retracted. Twoway valve:”open”, threeway valve port A-AB:”closed” *
Signal Input 10Vdc
Actuator stem extended. Twoway valve:”closed”, Threeway valve port A-AB:”open” *
Stroke
20mm
RunTime@ 50Hz
1min
0.5min
1.8min
Close-off Force
≥
600N
SpringReturnTime
≈
12s
SpringReturnDirection
Actuator stem extends
at power failure
Actuator stem retracts
at power failure
* Factory setting; can be reversed by action selector plugW3
OPERATION
General
The drive of a synchronousmotor is converted into linear
motion of the actuator stem by using a spur gear
transmission. The actuator stem is connectedwith the valve
stem by a button keyed retainer connection.
An integrated spring package limits the stem force to a
factory adjusted value in either direction.
Installedmicroswitches switch off the actuator precisely
when the specified stem force is reached.
Manual Operation
Actuatorswithout spring return are equippedwith amanual
operator used in case of power failure. Manual operation is
only possible after the power supply is switched off or
disconnected.
To operate push themanual operator knob down and turn
clockwise tomove the stem downward and counter-clockwise
tomove the stem upward. If the actuator returns to automatic
control, themanual operator knob unlocks automatically.
On actuatorswith spring return themanual operator is
located under the cover.
SpringReturn
TheML7425A,B spring return types provide a defined safety
position of the valve in case of power failure.
The spring return actuators are shipped from the factorywith
a shipment stop (to lock the knob) in order to allow
connection of the stem button retainer to the valve stem
without power supply.
Electrical Installation
The actuators are deliveredwith a pre-installed cable gland
PG13.5 and two additional knock outs for PG11 andPG13.5.
Cable length/diameter for fieldmounting:
•
Max. 200m/1.5mm
2
or
100m/1.5mm
2
(ML7420A3014)
CAUTION NO E
To avoidmalfunction it isnecessary to connect 24Vac
power andground (seeFig. 2).
CAUTION NO E
In caseof replacement pleasenote that theoverride
switchhasbeen changed (seeFig. 2).
Input Signal Failure
Bymeans of selector plugW1* the actuator can be selected
such, that in case of a signal input failure,(e.g. a brokenwire)
the actuator will run to one of the three positions:
0%:
actuator stem position for 0(2)Vdc
50%:
actuator stem in central position
100%:
actuator stem position for 10Vdc
W1 is set by the factory to 50%.
Input Signal Range
The range of the analog input signal Y can be changed by
changing the position of selector plugW2*
