Stearns 200, 55, 500, Spring-Set Disc Brakes, 300 User Manual

Installation and Service Instructions for Series
55,000; 55,200; 55,300; 55,400; 55,500 and 57,500

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 incorrectly. For
definition of limited warranty/liability, contact
Rexnord Industries, Inc., 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 install 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 personnel
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 causing the dust to
become airborne. Collect the dust in a
container, such as a bag, which can
be sealed off.

General Description

These series of brakes are spring-set,
electrically released. They contain one or
more rotating friction discs (4) driven by a
hub (16) mounted on the motor or other
shaft, except the 55,200 Series which has
the hub mounted on a shaft supported by
two brake bearings.

Operating Principle

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.

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).

I. Installation Procedure

To remove housing, follow instructions listed
under each individual brake series in Figure
2, then continue with the following steps.

A. Method of installing 55,300; 55,500;
57,500 plus 55,000 and 55,400 Brakes
with standard enclosure:

1. Remove hub (16) from brake assembly,

using caution to preserve alignment of
friction disc(s) (4) for ease of brake
assembly. Do not operate manual release
until brake is installed. When removing
hub from brake on multi-disc brakes,
check that hub slides freely. If not, file
area of discs contacting hub so that discs
slide freely without binding.

Note 1: On single-disc brakes the hub may
have moved far enough into brake to be

locked in

by stabilizing springs (161).
Remove springs from friction discs, but be
sure to replace them in same position and
proper location after hub is removed.
(Locate at 90° in recessed portion of square
hole, with prongs pointing into brake.)
Stabilizing springs (161) are only used on
single disc brakes with square hub and
splined hub with the teeth removed for
stabilizing spring clearance.

S-652-1

®

Spring-Set Disc Brakes

P/N 8-078-925-00

effective 11/6/97

Note 2: Check face of motor, machine or
foot mounting bracket to which brake is to
be mounted to be sure NEMA dimensions of

0.004” T.I.R. on concentricity and face run
out are met. Shaft run out is to be 0.002”
T.I.R. Maximum shaft end float is 0.020”. On
foot mounted brakes, dowels are
recommended for bracket.

2. Use a key (not supplied) tight fitting and
full axial length of hub (16). Slide hub on
shaft positioning inboard face of hub
about 3/16” from mounting face or at
5/16” for 57,500 Series. See Figure 3.
Securely tighten both hub set screws
(16S) with torque of 78 in-lbs on 1/4” and
156 in-lbs on 5/16”. Recommended
practice is to drill a set screw dimple into
shaft, especially on vertical installation.

3. Attach brake to mounting face by sliding
brake friction disc(s) (4) over hub,
engaging without force. Brake endplate
(2) face is to be tight against mounting
face.

Note 3: If motor or assembly is to be ceiling
or horizontally wall mounted, orient brake so
that plunger will be above solenoid frame at
final installation.

4. Install 3/8” – 16 cap screws (not supplied)
or 1/2” size for 57,500 Series to attach
endplate to mounting surface. Tighten to

manufacturer’s recommended torque.
Continue with Step D.

B. Method of installing 55,000 and 55,400
Series with waterproof, dust-tight
enclosure:

1. Remove screws (142S) and support plate
assembly (142).

2. Remove stationary disc(s) (3) and friction
disc(s) (4).

Note: Vertically mounted multi-disc brakes
have special pins which guide vertical
mounting springs. Observe color coded
sequence of springs from reinstallation.

See Notes 1, 2 and 3 in

Method I-A of

Installing Brakes with Standard Enclosure

.

3. Attach endplate (2) to mounting face and
tighten 3/8” – 16 cap screws (not
supplied) to manufacturer’s
recommended torque.

4. Use a key (not supplied) tight fitting and
full axial length of hub (16). Slide hub on
shaft positioning square inboard face of
hub 1/32” to 1/16” from unfinished cast
surface of endplate (2). See

Installation

Procedure,

A, Step 2 for set screw

tightening.

5. Reassemble friction disc(s) (4) and
stationary disc(s) in the same order, being
sure all slide freely without binding. If
vertical mounting springs are used, be
sure to reassemble in original sequence
or refer to Sheet 301.4.

6. Mount support plate assembly (142) and
torque screws (142S) evenly to 43 in-lbs.
Be sure plunger is above frame on
horizontal brakes. Continue with Step D.

C. Method of installing 55,200 Series:

1. Do not disassemble brake.

2. Bolt foot mounting bracket to a suitable
base.

3. For in-line coupling, follow coupling
manufacturer’s suggestions on alignment.

4. If installing pulley or sprocket on brake
shaft, do not use excessive force during
installation. Maximum overhung load at
center of keyway length is 150 lbs.

5. After alignment, dowels are suggested to
maintain alignment.

6. Remove housing (7). Continue with
Step D.

D. For all sizes

1. Refer to solenoid air gap, Table 2 in
Section IV-A. Follow Steps 1 and 2 for
checking and air gap adjustment, if
necessary.

2. See Section II,

Electrical Connection of

the Brake,

for coil connection.

3. Replace housing. On 55,300; 55,500 and
57,500 Series Brake, tighten housing nut
(15) 3/4 to 1 turn (8 in-lb) beyond
contacting the housing surface. On
55,000 and 55,400 Series standard
enclosure brake, tighten housing nut 1/4
turn (30 in-lb) beyond contacting housing.
On 55,000 and 55,400 Series DTWP
enclosure brake, housing nut gaskets are
provided. Tighten housing nut 1/2 to 3/4
turn (20 in-lb) beyond contacting gasket
on housing.

Note: If brake is

upside down

for later
ceiling mount, turn brake upright before
installing housing.

II. Electrical Connection of Brake

CAUTION: Inverter Motor and Special
Control Systems. This brake contains

either a single phase AC coil or DC coil that
requires instantaneous power within ± 10%
of rating at the coil. Aseparate power
source is required when this brake is used
in conjunction with a motor or control system
that limits voltage or current input (i.e.
inverter motors) or causes a ramping of the
power supply.

Note 1: Brake coil connections described
here cover common motor connections. For
nonstandard motor or control connections
contact respective supplier or Stearns
Division.

Note 2: On brakes with space heater,
connect to appropriate power source. Heater
is to be energized continuously, even during
storage, if rust may occur.

Note 3: Be sure lead wires to coil are not
tight or pinched, and that leads will not be
rubbed by friction disc, trapped between
solenoid plunger and frame, caught between
lever arm and endplate, or by linkage.

A. AC coils – single and dual voltage

1. All Stearns AC coils are single-phase.

Connect single voltage coils to any two
wires of single or three-phase power
source, or, for operation with motor
control, to any two motor leads of proper
voltage.

Method of connecting dual voltage coil for
use on high or low voltage is shown in
Figure 4. Observe the lead numbering
sequence for proper connection as shown
in next column.

2. To use a 230 volt coil (or a dual voltage

coil connected for 230 volts) with a
230/460 dual voltage three-phase motor,
the brake leads are connected across two

Figure 3

55,000 and 55,400 Series

Remove housing nuts (15) by unscrewing
from housing studs (150), remove
housing (7) by pulling back.

55,500; 55,300 and 57,500 Series

Remove housing nuts (15) by unscrewing
from housing studs (150), remove
housing (7) by pulling back.

55,200 Series

Remove wraparound sheet metal
housing (7) by turning wing-nut on
latch counterclockwise until latch
releases.

Figure 2