Stearns 1-048-151 User Manual

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personnel or damage to equipment
before any disassembly of the brake is
attempted or before the manual release
lever is operated on the brake.
2. Observe all cautions listed at the
beginning of this manual before
attempting to service brake.
3. Remove housing screws (15) and
housing (7) or (7A).
Wear adjustment
1. Normal friction disc wear will cause
solenoid air gap to become larger from
the original set 1/8” air gap. An
increase in stopping time and a slight
reduction in torque will consequently
occur. See Figure 6.
2. When the solenoid air gap increases to
1/4”, the brake must be adjusted. The
gap is measured between the mating
ground surfaces of the solenoid frame
and solenoid plunger.
Note: To measure air gap on brakes
mounted vertical above motor, push
plunger into frame until spring pressure is
felt. Holding firmly in this position,
measure air gap between mating (ground)
surfaces on solenoid frame and solenoid
plunger. If adjustment is made, check air
gap by again holding plunger as directed.
3. To decrease air gap, turn the wear
adjusting screw (10) clockwise until an
air gap of 1/8” minimum is attained.
To increase gap, turn screw
counterclockwise.
4. After adjustment, push in plunger and
allow it to snap out. Recheck air gap,
see Note.
5. Replace friction disc when wear area is
one half original disc thickness of 3/16”.
Friction disc replacement
1. Disconnect power source to brake.
2. Align friction disc (4) notches with the
two 1/4” flat head cap screws. Remove
the screws and slide entire brake off
motor and hub.
3. Remove housing support nut (19) and
solenoid mounting nut (19) from one
side of the solenoid mount. Slide
carriage bolt (sA) out the backside of
the endplate (2). Remove solenoid
spacer (3C) and shock pad (3G).
4. Slide old friction disc out the side of the
brake assembly.
5. Insert new friction disc between
endplate (2) and stationary plate (5).
Reassemble brake in reverse order of
Steps 2 & 3. Tighten the solenoid
mounting nut (19) to 15 lb-in to
compress the shock pad (3G).
Note: If solenoid buzz is noted, readjust
solenoid mounting nut (19) to “tune out”
the buzz.
6. See 
Wear adjustment. It may be
necessary to turn wear adjust screw
(10) CCW for clearance.
7. Repostion the housing support hot (19)
165" from the top of the housing bolt.
8. Replace housing.
9. Restore power to brake.
Coil or solenoid assembly replacement
1. Disconnect coil (12C) from circuit.
2. Cut the plastic wire tie holding the coil
leads onto the housing stud (18).
3. Remove housing and solenoid
mounting nuts (19) and lift solenoid /
coil assembly off the mounting bolts.
4. Remove plunger guide (82A) by lifting
out of top of solenoid frame. Coil (12C)
has a lock tab, located at top of coil
opposite lead wire side, which is
pressed against coil and coil is slid
sideways from solenoid frame.
5. For coil replacement, inspect and clean
solenoid assembly. Install the new coil
in original solenoid frame or original
coil in new solenoid frame with the lead
wires positioned as before. Install
plunger guide(s) in reverse order of (4).
5A. For solenoid assembly replacement,
remove plunger screw (9) and plunger
nut (9B). Install new plunger (29A)
with new plunger screw and nut.
6. Reassemble brake in reverse order of
Steps 1, 2 and 3. Tighten solenoid
mounting nuts (19) to 15 lb-in of torque
to compress the shock pad (3G).
Note: If solenoid buzz is noted, readjust
solenoid mounting nut (19) to “tune out”
the buzz.
7. Reposition the housing support hot (19)
165" from the top of the housing bolt.
8. Replace housing.
9. Restore power to brake.
VI. Troubleshooting
A. If brake does not stop shaft properly
or overheats, check the following:
1. Is brake manually released rather than
electrically released while motor is
running?
2. Is friction disc excessively worn,
charred, or broken?
3. Has hub become loose and shifted on
shaft?
4. Is hub clean, and does friction disc
slide freely?
5. Does stationary plate slide freely on
guide pins?
6. Are pressure springs improperly
assembled, or broken?
7. Is solenoid air gap adjusted correctly?
See 
Wear Adjustment.
8. Does solenoid linkage move freely?
9. Is voltage supply at coil correct?
10. Are controls which govern start or
stop of braking cycle operating
properly?
Figure 6