Stearns 87,000 Series Operating instructions

Important
Please read these instructions carefully
before servicing your Stearns brake.
Failure to comply with these instructions
could cause injury to personnel and/or
damage to property if the brake is
serviced or operated incorrectly. For
definition of limited warranty/liability,
contact Rexnord Industries, Inc., Stearns
Division, 5150 S. International Dr., Cudahy,
Wisconsin 53110, [phone].
Caution
1. Servicing shall be in compliance with
applicable local safety codes including
Occupational Safety and Health Act
(OSHA). All wiring and electrical
connections must comply with the
National Electric Code (NEC) and
local electric codes in effect.
2. To prevent an electrical hazard,
disconnect power source before
working on brake. If power disconnect
point is out of sight, lock disconnect in
the off position and tag to prevent
accidental application of power.
3. Be careful when touching the exterior
of an operating brake. Allow sufficient
time for the brake to cool before
disassembly. Surface may be hot
enough to be painful or cause injury.
4. Do not operate brake with housing
removed. All moving parts should be
guarded.
5. After usage, the brake interior will
contain burnt and degraded friction
material dust. This dust must be
removed before servicing or adjusting
the brake.
DO NOT BLOW OFF DUST using an
air hose. It is important to avoid
dispersing dust into the air or inhaling
it, as this may be dangerous to your
health.
a) Wear a filtered mask or a respirator
while removing dust from the inside
of a brake.
b) Use a vacuum cleaner or a soft
brush to remove dust from the
brake. When brushing, avoid
causing the dust to become
airborne. Collect the dust in a
container, such as a bag, which can
be sealed off.
6. Maintenance should be performed
only by qualified personnel familiar
with the construction and operation of
the brake.
7. For proper performance and
operation, only genuine Stearns parts
should be used for repairs and
replacements.
Warning! Any mechanism or load held
in position by the brake should be
secured to prevent possible injury to
personnel or damage to equipment
before any disassembly of the brake is
attempted or before the manual release
knob or lever is operated on the brake.
Instructions
1. To remove housing, follow instructions
listed under each individual brake
series shown in next column, then
continue with the following steps.
2. To replace coil (12A) or (12B),
disconnect power source lead wires
from coil by removing the screws or
connectors. It is not necessary to
remove the support plate assembly
(142). If used, remove two coil leads
and two arc suppression leads from
DC switch (157).
3. Remove solenoid link screw (13C), nut
(13N) and lift out solenoid plunger
(29).
4. For metallic plunger guides (82),
remove plunger guide screw(s) (84).
Remove both plunger guides (82) by
prying up on the flanges. Discard
plunger guides.
To remove non-metallic plunger guides
(82), remove screw(s) (84).
®Brake Replacement Parts
P/N 8-078-956-02
effective 8/20/99
Item
No.
Description of Parts Included
in Kit (Kit contents, will vary
based on style of coil)
Qty.
per
Kit
12A
139
139S
139W
82
84
84W
12AT
No. 5 coil or No. 6 coil
Lead wire and terminal assy.
Terminal screw
Terminal lock washer
Plunger guide
Screw - plunger guide
Lock washer - plunger washer
Crimp terminal
1
2
2
2
2
1
1
2
Service Instructions for No. 5 & No. 6 Coil Assemblies
DC Voltage Coils
Series 87,000; 87,200; 87,400; 87,600 and 87,700 Disc Brakes
87,200 Series
87,700 Series
*Item 157A replaces item
157 in some brakes.
Remove manual release knob (148),
two housing nuts (15) or bolts holding
housing endplate, and housing (7) by
pulling back.
a) Remove the brake and motor as a
unit from the gear reducer.
b) Remove four housing cap screws
(15) lock washers (15W), housing
(7) and shaft assembly.
87,000 Series
a) Remove any accessories, sprockets,
sheaves, etc. from brake shaft on
housing side.
b) Remove manual release knob (148),
two housing nuts (15), and housing
(7) by pulling back.

Insert shim stock or other thin gauge
material at top center of coil between
coil and solenoid frame. Push to
release lock tab while lifting up on
plunger guide. Repeat for other
plunger guide.
5. Slide coil (12A) or (12B) out from
solenoid frame (79) in the direction of
the coil leads. If necessary, tap coil
lightly with a soft hammer. If solenoid
coil had burned out, be sure to remove
all foreign material from the solenoid
plunger (29) and solenoid frame.
6. Install new coil (12A) into solenoid
frame with same relative position as
old coil. Assemble new non-metallic
plunger guides (82) by inserting into
position and pushing down until lock
tab snaps under top bar of solenoid
frame. Install plunger guide screw(s).
With encapsulated coils (have
terminals) check that lock tabs allow
free movement of plunger. If
movement is restricted, file chamfer
approximately 1/16 x 45° on coil at
lock tab area.
Install new coil (12B) (on all except
87,700) with coil leads at upper left of
solenoid frame. Follow Step 6 on
installation of guides and screw(s).
On 87,700 install coil (12B) partially
into frame with leads at lower left, then
left side plunger guide and left screw.
Tighten screw. Move coil to right,
install right side plunger guide, screw
and tighten.
7. Reassemble plunger into solenoid by
reversing Step 3.
8. Install crimp terminals (12AT) on leads
of new coil.
9. Connect the proper two coil leads and
the two arc suppressor leads to DC
switch (157) if used. See DC Voltage
Coil Connection, Sheet 8-078-950-00.
Note: If new coil uses an electronic
switch (157A), the arc suppressor
and mechanical switch do not need
to be used.
10. Be sure lead wires to coil are not tight
or pinched; leads will not be rubbed;
leads will not be trapped between
solenoid plunger and frame.
11. Manually lift solenoid plunger to
maximum travel. Depress and allow
solenoid plunger to snap out several
times. Measure solenoid air gap
between mating surfaces of solenoid
frame and solenoid plunger. (On
vertically mounted brakes, it will be
necessary to push solenoid plunger
into solenoid frame to the point where
spring pressure is felt, before
measuring solenoid air gap). The
operating solenoid air gap
measurement is 13/16 to 15/16.
12. The solenoid air gap may be
increased by raising or decreased by
lowering the wrap spring stop (76). To
accomplish this, loosen two stop
screws (76S), move wrap spring stop
slightly and retighten screws. Repeat
Step 11 after each change in wrap
spring stop position to obtain air gap
measurement of 13/16 to 15/16.
13. Reconnect coil leads.
14. Replace housing, screws and manual
release knob in the reverse order of
the appropriate point in Step 1. On
dust-tight waterproof enclosure
replace gaskets.
15. Caution! Do not run motor with brake
in manual release position. It is
intended only for emergency manual
movement of the driven load, not as a
substitute for full electrical release.
NOTE: For complete instructions, with
troubleshooting, request sheet
applicable to the series of brake that
you have.
Refer to Instruction Sheet 8-078-950-00
for wiring.
Copyright© 1999 by Rexnord Industries, Inc.
Rexnord Industries, Inc., Stearns Division, 5150 S. International Dr., Cudahy, Wisconsin 53110 [phone] Fax [phone]