®Spring-Set Disc Brakes P/N 8-078-950-00
effective 01/15/18
Wiring and Service Instructions
for DC Voltage Coils
56,XXX and 8X,XXX Series
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, LLC, Stearns Division,
5150 International Dr., Cudahy,
Wisconsin 53110, (414) 272-1100.
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.
Caution1! Due to high initial current
demands of a DC solenoid, a separate DC
power source of adequate current capacity
is usually required.
Caution 2! Never use a series resistor to
drop power supply voltage to the coil as
brake malfunction will result.
Caution 3! For electrical release of brake,
apply full rated coil voltage instantly. Do not
increase voltage slowly.
The (red +) lead wire must be connected
to positive and the (black - ) lead wire to
negative.
Do not use a half wave rectifier
56,XXX and 8X,XXX
These Stearns DC coils are single
voltage dual winding. A high current
pull-in winding is initially energized to
start the plunger movement, while a low
current holding winding is momentarily
shunted from the circuit until the plunger
has pulled in. The electronic switch
design incorporates an electronic timing
circuit to allow the plunger to pull in,
then electrically switch to the holding
winding. Polarity of the power supply to
the electronic switch and coil must be
maintained. Refer to Figure 2 or 3 for
proper wiring. Refer to Figure 4 (next
page) for approximate switch position.
Table 1: Air Gap Settings
Figure 2
Class H Class B
red
black
black
yellow
Nominal Static
Torque (lb-ft) Air Gap
56,X00 Series
1 disc 3/8”
2 disc 7/16”
3 disc 1/2”
87,X00 Series
all torques 7/8” to 15/16”
81,X00; 82,X00 and 86,X00 Series
all torques 1-3/8” to 1-7/16”
Class H
Class B
blue
blue yellow orange
yellow orange
Figure 1
Figure 3
