STT113 TOWER CRANE OPERATION AND SERVICE MANUAL
5B-6
working principle of ho
Ⅲ
Ⅲ
Ⅲ
Ⅲ
isting winch
Three speed motor of hoisting winch drive the drum to running by reducer.
The electric interlock control panel control the hoisting winch to carry out three
raising speed and three lowering speed. It is low speed, intermediate speed and
high speed. When start up the low speed motor ( 16 grade ), the stator winding
and disk brake coil be made contact simultaneously, declutch the brake then
startup the hoisting winch by low speed ( MV ), Thereafter, its may switch to the
intermediate speed motor( PV ) and may continue switch to the high speed to
work.( GV ) in light load condition.
When stop motion, the electric control make the time which the brake affected
lag 0.5
－
1s in order to prevent braking intensively to damage brake.
The intermediate speed shift (PV ) and high speed shift ( GV ) of hoisting winch
is work shift. The low speed (PV) used to start up and low location, generally it
is not allow work long time.
Adjusting brake of three speed hoisting motor (see Fig. 5
Ⅳ
Ⅳ
Ⅳ
Ⅳ
-1-2)
（
I
）
. Adjusting brake moment as following:
1. takeoff pin (54) and plate (53);
2. Takeoff manual adjustable lever
（
52
）
；
3. takeoff the bolt (29);
4. takeoff whole cover cap (40);
5. Tighten up three spring adjusting nuts (37) simultaneously. The travel motion
distance of three nuts is same when adjusting three nuts, precession the nut
according to the clockwise, the brake moment increased; precession the nut
according to counter-clockwise, the brake moment reduced. It’s until
hoisting max rating load, the load till not subsiding
.
