INDELAC CONTROLS 22018-DH, Installation, Operation & Maintenance Manual

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PART #22018-DH - High-Resolution Positioner
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light (CLOSE or OPEN) will flash. If an appropriate relay option module is installed, the Fault relay
output on the option module will turn off (indicating a fault) when either of the limit switches is
reached.
TRIP SETTING:
The Trip Setting is used to limit the motor current and is set using the TRIP ADJUST pot (see
OUTLINE) as shown below.
The setting should be adjusted to a comfortable level
above the running current expected for the actuator and
its load. When the motor current exceeds the trip setting,
the motor is turned off and a fault condition is indicated
(see FAULT INDICATORS).
While the Electronic Surge Limiting feature of the DHC-
400 reduces the high in-rush currents during motor starts,
the trip setting is used to reduce the current required from
the battery/power supply when the motor stalls or
encounters an excessive load. Without the trip setting, a
costly high capacity battery/power supply would be
needed to avoid collapse of the battery/power supply voltage. The combination of the trip setting
and electronic surge limiting allows the use of a more moderate battery/power supply and smaller
gauge wires for a given length (see WIRE TABLE).
The trip setting essentially performs the same function as commonly used torque switches.
However, it should be noted that the actuator and valve components (gears, couplings, seats, etc.)
also place a load on the motor. These components will vary with temperature and age, and therefore
the torque on the load will vary accordingly.
STALL DETECTION FEATURE:
The Stall Detection feature of the DHC-400 detects when there is no motion after a certain amount
of time while the motor is turned on (see FAULT INDICATORS). This condition can arise if the
motor's stall current is less than the current trip setting (see TRIP SETTING). If the motor current is
greater than 0.5A when no motion is detected, a stall fault is indicated.
When one of the motor wires is disconnected, no motion will be detected, but the motor current will
be zero. Therefore, if the motor current is less than 0.5A when no motion is detected, a no motion
fault is indicated.
If the feedback pot is mechanically disengaged, no motion will be detected, but the motor current
will be the normal running current. Therefore a stall or a no motion fault may be indicated, depending
on whether the running current is greater or less than 0.5A.