9
-48- (Fig.5) is the pinion -49- (Fig.5) which is connected to the shaft -46- by an adjustable friction clutch. On this pinion,
the motion required for driving the resistance or current transmitter is sensed. The arrangement of cams
and microswitches of the signalling unit is shown in Fig.4. Shoulders of the cams -30- deflect the levers -34- and -35-,
which in turn control the microswitches -36- (SO) and -37- (SZ). When adjusting the signalling and position-limit
switches and the transmitter, the output shaft of the actuator should be moved to the position in which changing-over
of the microswitches should take place or the required position of the transmitter should be reached.
When adjusting the signalling switches, the following procedure should be used: First, loosen the screws -32-
(for SZ) or -33- (for SO), as shown in Fig.4. Then, turn the cam -30- or -31- in the direction of the arrowhead, i.e.,
anticlockwise for the CLOSE signalling microswitch (SZ) and clockwise for the OPEN signalling microswitch (SO), till
the microswitch closes. In this position, hold the cams and retighten the lock screws.
Caution!
After any manipulation of the lock screws in the control section of the actuator, these screws should be secured
against loosening due to vibrations by a drop of quick-drying varnish. If the screws have secured previously in this way
then, during adjustment, varnish residue should be removed and the surface should be properly cleaned.
c) Adjusting mechanism of resistance transmitter - Fig. 6
This mechanism consists of 2 geared rockers -51- and -55- on which spring -52- is hung. A rail with pins -53- provides for
mutual sliding movements of the two rockers. This group is rotatably mounted on pin -54-. The whole mechanism is mounted
onto the basic control plate -67- (see Fig.2). The geared rockers are in mesh with pinion -43- of the transmitter (Fig.7) or pinion
-49- (Fig.5). Then, the position of pin -54- determines the gear ratio of the adjusting mechanism, i.e., the angle of positioning
the transmitter and the local position indicator is always 160° for different values of working stroke of the actuator and thus for
different amounts of displacement of the camshaft in the signalling unit. This ensure that, at any working stroke, the rated
value of the transmitter signal, i.e., 100 ohms, is always available.
d) Position transmitters
Resistance transmitter, including position indicator - Fig.7
The heart of this unit is a resistance transmitter -52- whose rated value is that of the resistance signal of 100 ohms.
The transmitter has a shaft which has been brought out on both sides. Put on the shaft at the lower end, the pinion -43- has
been arranged to slip on the shaft in either end position of the transmitter, a feature that is extremely suitable for adjusting
the unit. At the upper end of the transmitter shaft, the position indicator -40- is mounted by a screw -41- so that it can be
adjusted with respect to the inspection hole in the control box cover.
Adjustment of resistance transmitter and position indicator
For positioning of the transmitter, the procedure is the following: In the CLOSE position of the output shaft, press down
the geared rocker -51- (Fig.8) to move it towards the transmitter out of engagement with the pinion -49- (Fig.5). Then, turn the
rocker clockwise up to the stop formed by a column under the signalling unit. Finally, bring the rocker into engagement with
the pinion -49-, whereupon the pointer of the transmitter should indicate 0°. If this is not the case, withdraw the rocker -51-
from the stop and depress the rocker -55- to release the transmitter pinion. Set thetransmitter pointer near the transmitter
scale division line 0° so that, after bringing the rocker -55- into engagement with the transmitter pinion, their teeth fit into one
another correctly. This can be checked by carefully turning the transmitter shaft. Then, throw the rocker -51- out of
engagement and move it up to the stop, exerting an increased force. (After the transmitter pointer has been set to 0°
Open
Closed
Terminal numbers
on terminal board
PO
15-16
14-15
PZ
18-19
17-18
Open
Closed
SO
21-22
20-21
SZ
24-25
23-24
Contact closed
Contact open
Operating diagram of position-limit and signalling switches
Summary of Contents for MODACT MON 100/130-100
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