Stearns 1-056-700 Series Quick guide

Installation and Service Instructions
for 1-056-700 Series (rev. C)
Double C-Face Coupler
®Spring-Set Disc Brakes P/N 8-078-905-69
effective 05/16/2022
Typical Nameplate
Important
Please read these instructions carefully
before installing, operating, or servicing
your Stearns Brake. Failure to comply with
these instructions could cause injury to
personnel and/or damage to property if the
brake is installed or operated incor-rectly.
For definition of limited warranty/liability,
contact Rexnord Industries, LLC, Stearns
Division, 5150 S. International Dr., Cudahy,
WI 53110, [phone]
Caution
1. Installation and servicing must be
made in compliance with all 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. Do not operate the brake in
atmospheres containing explosive
gases or dusts.
3. To prevent an electrical hazard,
disconnect power source before
working on the brake. If power
disconnect point is out of sight, lock
disconnect in the off position and tag to
prevent accidental application of power.
4. Make certain power source conforms to
the requirements specified on the brake
nameplate.
5. Be careful when touching the exterior of
an operating brake. Allow sufficient time
for brake to cool before disassembly.
Surfaces may be hot enough to be
painful or cause injury.
6. Do not operate brake with housing
removed. All moving parts should be
guarded.
7. Installation and servicing should be
performed only by qualified person-
nel familiar with the construction and
operation of the brake.
8. For proper performance and operation,
only genuine Stearns parts should be
used for repairs and replacements.
9. 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 caus-ing the dust to become
airborne. Collect the dust in a container,
such as a bag, which can be sealed off.
10. Caution! While the brake is equipped
with a manual release to allow manual
shaft rotation, the motor should not be
run with the manual release engaged,
to avoid overheating the friction disc(s).
General Description
The 56,700 Series coupler is a spring-set,
electronically released brake, containing
either one or more rotating friction discs (4)
driven by a hub (16) mounted on the motor
shaft. The double C-face allows the brake to
directly couple a C-face motor to a C-face
gear reducer.
Operating Principle
Warning! Do not apply overhung or die load
to brake output shaft.These series contain
one or more friction discs (4) assembled
alternately between the endplate (2) friction
surface, stationary disc(s) (3) and pressure
plate (also called stationary disc) (3). The
stationary disc(s) are restrained from rotating
by being keyed into the endplate. With the
brake released, all disc pack components are
free to slide axially and the friction disc(s) to
rotate.
Brake release occurs when the solenoid coil
is electrically energized, causing the solenoid
plunger to travel a specified distance and
through a lever system, overcoming the
pressure spring force. This action releases
the clamping force on the disc pack, thereby
allowing the friction disc(s) and brake hub to
rotate.
Brake sets and torque is produced when
electric current to the solenoid coil is
interrupted, thereby collapsing the solenoid
magnetic field. The solenoid plunger returns
to its original de-energized position allowing
the lever arm to move forward by virtue of
the compressed torque springs. This action
compresses the disc pack components which
applies a retarding torque to the brake hub
and ultimately restores the brake to a spring-
set static condition.
Tools required for installation and servicing:
3/8” hex wrench 5/16” nut driver
5/16” hex wrench 1/4” screwdriver
3/16” hex wrench 8” adjustable wrench
Figure 1
For replacement parts refer to
sheet part number 8-078-906-07.
Instructions and parts list also
available at
www.stearnsbrakes.com.

Position hub to X as shown:
X=.32” (8.1mm) for 1 & 2 disc (1.5 - 15 lb-ft)
X=.19” (4.8mm) for 3 disc (20 & 25 lb-ft)
Place hub on motor shaft. Tighten set screws to motor shaft.
Connect coil lead-
wires to power
supply. Refer to
nameplate for volt-
age rating.*Caution:
Keep wiring away
from pinch points
and moving compo-
nents.
12
6
3
X
BRAKE MOUNTING (Manual Adjust) 1-056-700
* Stabilizer clips
are for use on
single disc units
only. Position
clips opposite
set screw holes.
Remove support plate screws and
lift support from brake
Reposition support plate on endplate and
tighten mounting screws to 55 lb-in.
Install new friction disc(s) and
stationary disc(s) as shown.
Remove and discard old friction disc.
4
2
13
clockwise
For brakes
with vertical
sprngs see
Figure 5A
or 5C.
FRICTION DISC REPLACEMENT SERIES 1-056-700
2
Note: Friction discs can wear to 1/2 their original thicknes, or .093”
A. Remove housing nuts and slide tie bolt out of brake.
B. Remove housing from endplate.
4
* For vertical assembly
of 20 & 25 lb-ft brakes
refer to page 3.
Slide endplate over hub noting position of stabilizer clips, if
used. (Refer to Friction Disc Replacement view 3 and
3A). Mount
brake
endplate to
motor C-face
using the
four tie bolts.
Finger
tighten.
5
A. Slide housing and shaft assembly onto mounting studs, rotating
shaft until keyway is aligned. Be sure housing is assembled with
access windows in same position as shown in Figure 1, page 1.
B. Mount and secure brake/motor assembly to
C-face mounting register of reducer.
Using four 3/8 - 16 nuts and
lockwashers, tighten to 30-35 ft-lb.
clockwise
7
counter-clockwise
5

Lift plunger/solenoid
lever assembly
out of coil.
Remove plunger guide.
A) Re-insert plunger into coil; drop
pivot pin into cradle of support plate.
B) Remove screwdriver.
A) Insert new coil.
(Lead wires in same
position as old coil.)
B) Insert plunger guide.
Insert screwdriver
between support
plate and lever
arm and pry
forward.
6
5
4
A
B
A
B
Remove housing and disconnect power and wiring to coil.
Discard coil.
Vertical Brake Assembly
Single disc brakes (1.5, 3 & 6 lb-ft) are uni-
versal mount and do not require separator
springs. Double disc brakes (10-15 lb-ft.) are
universal mount but require separator springs
which are preassembled to the stationary
disc. These discs are inserted spring first into
the brake. Refer to figure 2A below.
Installation Procedure for 20 and
25 lb-ft brakes if mounted vertical
to motor shaft (These brakes are factory
assembled for horizontal operation.)
Remove support plate by loosening the three
mounting screws. Remove stationary discs
and friction discs.Using the spring kit pro-
vided with this brake, insert three springs of
identical color into each stationary disc hole.
Springs are inserted from the side opposite
the indent mark (see Figure 2B). Stationary
disc should be placed on a clean flat surface
with a clearance hole to allow the tip of the
spring to extend through the bottom side of
the sta-tionary plate. Using the 1/8” pin pro-
vided and a hammer, drive the spring until
the large coil diameter bottoms out against
the disc.Reassemble the disc pack with the
stationary discs in the proper arrangement
shown in Figure 2C.
Mount support plate and torque screws
evenly to 55 lb-in.
Reconnect coil and replace housing per installation instructions, page 2.
2
13
3
To decrease air gap, turn both adjusting
screws (10) clockwise.
2
To increase air gap, turn both adjusting
screws (10) counterclockwise.
1
As friction disc wear the air gap will increase. When plunger gets to the reset position, the air gap must be adjusted.
counter-clockwise
Torque
Disc Torque
11.5, 3 & 6
210 & 15
320 & 25
Min/Max
.38” - .69”
.45” - .69”
.50” - .69”
56,X00 Series Air Gap*
AIR GAP ADJUSTMENT 1-056-700
VERTICAL SPRING ASSEMBLY 1-056-700
Figure 2B
Figure 2C
Figure 2A
COIL REPLACEMENT SERIES 1-056-700
Note: Air gap can be adjusted witout disassembly. Remove cover
plate (7A) and manual release plate (7B) and adjust as shown above.
7A 7B
Maximum gap should never exceed .69”.

Torque Adjustment
Brake is factory set for nominal rated static
torque which is maximum torque. Torque
may be decreased up to 50% for increased
stopping times up to 2 second stop time.
The torque on the 1-1/2 lb-ft brake may not
be reduced.
Turn both spring adjustment screws (11),
Figure 3, equal amounts counterclockwise
to decrease torque. See Table A for torque
reduction permissible amounts.
11 11
10
10
Figure 3
Nominal Original Maximum % Torque
Static Spring Counter- Reduction
Torque Height clockwise per
(lb-ft) (inches) Turns Turn
1-1/2 1.56” - -
3 1.50”
6 1.47”
10 1.53” 7 7%
15 1.53”
20 1.53”
25 1.47”
TABLE A
COIL FAILURE
SUPPLY VOLTAGE CAUSE SUPPLY VOLTAGE CORRECTION
Line voltage >110% of coil rating Reduce voltage or replace with prop-
er rated coil
AC input on a DC coil Replace rectifier or replace with
proper rated coil.
Excessive voltage drop during
inrush time
Increase current rating of power
supply.
WIRING CAUSE WIRING CORRECTION
Leadwires interfering with plunger
pull-in
Reroute wiring away from plunger
and other moving components.
Excessive voltage drop during
inrush time
Increase leadwires size from power
supply
Coil leadwire shorted to ground Replace coil or leadwire and protect
with wire sleeving
SOLENOID ASSEMBLY CAUSE SOLENOID ASSEMBLY
CORRECTION
Plunger not seating flush against
solenoid frame
Loosen solenoid mounting screws
and reposition frame to allow full
face contact
Plunger cocked in coil preventing
pull-in
Realign solenoid frame
Excessive solenoid/plunger wear
at mating surface
Replace solenoid assembly
Broken shading coils Replace solenoid assembly
WORN PARTS CAUSE WORN PARTS CORRECTION
Excessive wear of solenoid link
arm and/or shoulder bolt
Replace link arm and link bolt; also
inspect plunger thru-hole for
elongation
Plunger guides worn down and
interfering with plunger
movement
Replace guides
APPLICATION CAUSE APPLICATION CORRECTION
Machinery cycle rate is exceeding
brake rating
Reduce brake cycle rate or use alter-
nate control method
High ambient temperature
(>110%) and thermal load
exceeding coil insulation rating
Use Class H rated coil and /or find
alternate method of cooling brake
Brake coil wired with windings of
an Inverter motor or other
voltage/current limiting device
Wire coil to dedicated power source
with instantaneous coil rated voltage
MISCELLANEOUS CAUSE MISCELLANEOUS CORRECTION
Wrong or over tightened torque Replace with proper spring or refer
to Installation section for proper
spring height
Excessive air gap Reset, refer to Installation Section 4
EXCESSIVE WEAR / OVERHEATING
AIR GAP CAUSE AIR GAP CORRECTION
Low solenoid air gap Reset air gap (refer to Air Gap
Adjustment)
Disc pack dragging Inspect endplate, hub and discs for
dirt, burrs, wiring and other sources
of interference preventing disc “float”
CYCLE RATE CAUSE CYCLE RATE CORRECTION
Brake “jogging” exceeding coil
cycle rate
Reduce cycle rate or consider alter-
nate control method
Thermal capacity is being
exceeded
Reduce cycle rate, use alternate
control method or increase brake
size
ALIGNMENT CAUSE ALIGNMENT CORRECTION
Broke endplate not concentric to
motor C-Face
Motor register must be within
.004” on concentricity;
Motor shaft runout is excessive Must be within .002”; runout;
consult motor manufacturer
Brake is being operated on a
incline greater than 15° above or
below horizontal
Vertical separator springs must be
used to prevent discs from
becoming cocked
WORN PARTS CAUSE WORN PARTS CORRECTION
Friction disc excessively worn
(disc can wear to 1/2 original
thickness or .093”)
Replace friction discs.
Endplate, stationary disc or
pressure plate warped
Replace warped or worn component
Linkages and/or pivot pins worn Replace all worn components
Motor shaft endfloat excessive Endfloat must not exceed .020”; con-
sult motor manufacturer
HUB CAUSE HUB CORRECTION
Burr on hub interfering with disc
“float”
File off burr
Set screw backed out and
interfering with disc
Retighten set screw; use Loctite®
242 to help secure
MISCELLANEOUS MISCELLANEOUS
Solenoid plunger not pulling
completely
Check line voltage (±10% of
nameplate rating) or replace worn
solenoid assembly
Wiring is restricting disc pack
movement
Reroute wiring
Excessive stop time
(2 seconds or greater)
Increase brake size/torque or use
alternate control method
High Ambient temperature
(in excess of 110°F)
Reduce cycle rate or use alternate
method of cooling
TROUBLESHOOTING
Rexnord Industries, LLC, Stearns Division, 5150 S. International Dr., Cudahy, WI 53110, [phone] Fax: [phone] www.stearnsbrakes.com
TORQUE ADJUSTMENT