Operating instruction ERU Knife Gate Valve K1 electric actuator
BA46E042
Jul 2009
Rev. 11
ERHARD-Armaturen D-89502 Heidenheim Postfach 1280
(07321) 320-0 (07321) 320 491 e-mail:info@erhard.de
Internet: http://www.erhard.de
Electrical connections must be made according to operating instructions as well as
switching and connection plan of the electro actuator manufacturer (travel distance,
torque and thermal switches, heater motor). Prior to installation the isolation resistance
of the motor must be measured. In case it is below 500 kΩit means there is humidity
in the winding. The motor must be removed for drying and be warmed up by means of
a hot-air blower or in a heated chamber: maximum admissible temperature = 100°C.
Inching and emergency manual operation
Attention:
If a foreign part will be trapped during operation of the valve the torque switch for the
corresponding direction will trip and switch off the motor.
The time between tripping of the torque switch and separation of the motor from mains
depends on signal travelling time. If now a new command will be given for the previous
direction without having rotated the valve sufficiently far enough into the opposite
direction, the torque will rise. If this procedure will be repeated several times the
momentum will be cumulated. The valve and its actuator parts are not designed for
such a case of failure and may be damaged.
We point express to the fact that such an "Inching" is not admissible.
Inching is admissible as follows:
If the torque switch trips at an intermediate position, first, it must be travelled far
enough into the counter direction until the torque switch reaches completely its home
position. Only then, restart into that direction in which the failure has occurred is
admissible. At this procedure torques will be reached which correspond with the set
momentum on the torque switch. Moreover, the foreign part can loosen and be flooded
out from the seat area.
Operating by emergency manual operation (hand wheel):
If the valve will be operated by hand wheel of the electric actuator the torque switches
have no securing effect.
If a foreign part is trapped at an intermediate position, excessive force may lead to
damages on the actuator parts - especially at heavy geared down equipment.
Therefore it must be observed:
If during emergency manual operation a resistance will be noticed, one turn into the
counter direction must be performed prior to rotating into that direction in which the
failure has been detected (rinsing out the foreign part). Operation should be performed
at utmost care, in no case use excessive force, if required rinsing should be repeated.
The profile gasket has been set to nominal pressure in the factory (biased). At low
operating pressures the profile gasket can be released after the pressure test of the
pipeline according to actual operating pressure. For doing this, the screws on the
