8
transmitted to the tripping lever -45- or -46-. When the torque on the output shaft of the actuator reaches the value to
which the torque-limit switching unit has been adjusted, the tripping lever depresses the button of the corresponding
microswitch so that the electric motor is disconnected from the mains, thus stopping the actuator.
Adjusting procedure of the torque-limit switching unit
To adjust a different tripping torque from that adjusted at the factory, the procedure is the following: Loosen the lock
nut -44- (see Fig.3) and then the lock screw -25- (for the CLOSE direction) or -26- (for the OPEN direction). Place
a screwdriver in the slot of the upper segment -23- or -24- and turn the segment till the slot in the segment -27- or -28-
tallies with the respective scale graduation. This scale division can be determined so that the difference (in Nm) between
the maximum and the minimum adjustable torques is divided by the number of divisions between the marks of the
minimum and maximum torques. In this way, the amount of tripping torque (in Nm) per scale division is obtained, making
it possible to determine by interpolation the scale division with which the slot in the segment -27- or -28- should tally.
The red division line nearer to number 10 marks the point of adjustment of the maximum tripping torque, whereas another
division line shows the point of adjustment of the minimum tripping torque. The torque control unit should never be
adjusted so that the slot in the lower segment is outside the zone marked by the colour scale division lines.
After adjustment of the tripping torque, retighten the lock screw -25- or -26- and the lock nut -44-.
b) Signalling unit - Fig.4.
This unit transmits an electrical signal to indicate the position of the output shaft of the actuator, drive of the unit being
provided via gear wheel -38- by the output shaft through a multistage gearbox to the cams -30- and -31- which control
the OPEN signalling microswitch -36- (SO) and the CLOSE signalling microswitch -37- (SZ). The instant of operation of
the signalling switches can be selected at any point of the working stroke of the actuator except the narrow band about
the end positions. (The signalling switch should close before the position-limit switch while the output shaft is still moving).
The upper cam -37- operates in the CLOSE direction, whilst the lower cam -36- operates in the OPEN direction.
Designed as an independent unit, the signalling unit shown in Fig.4 has been assembled on the support -39- under
which there are gears arranged as shown in the kinematic diagram of the Fig.5. This gearing has been assembled so that
the adjusting wheel K3 can be moved to different levels (I, II, III, IV, V) after loosening of the lock screw -47-. In this way,
the ranges of adjustment of the signalling switches and the transmitter can be changed, depending on the working stroke
of the actuator. Fig.5 is a table showing the ranges of adjustment for the individual positions of the adjusting wheel K3.
Adjustment of the signalling unit
If the ranges of adjustment of the signalling switches and the transmitter are required to be changedthe position of
adjusting wheel K3 should be changed. For adjustment of the wheel K3, the signalling unit should be withdrawn from
the control box (which is possible due to a sufficient length of lead-in wiresof the microswitches). This can be done
after removal of the 4 screws -66- (Fig.2) used for mounting the unitonto the base plate. After the signalling unit has
been adjusted to the required range it should be brought back into its original position. Before retightening the screws
-66-, the correct meshing of gears K1 and K2 should be checked (see Fig.5). Put on at the lower end of the camshaft
Legend:
30 – CLOSE direction cams
31 – OPEN direction cams
32 – Screws of CLOSE direction cams
33 – Screws of OPEN direction cams
34 – OPEN direction lever
35 – CLOSE direction lever
36 – OPEN direction microswitch (lower)
37 – CLOSE direction microswitch (upper)
38 – Drive gear
39 – Supporting plate of signalling unit
The encircled numbers correspond to the numbers
of terminals on the terminal board of the actuator.
The microswitches can be used only as one-circuit devices.
Two voltages of different vales or phases should not be ap-
plied to contacts of the same microswitch.
Fig.4 -
Signalling unit
Diagram of microswitches
31
32
34
36
37
38
39
30
33
35
1
2
4
Содержание MODACT MON 100/130-100
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