Warner Electric PRB-H - Manual (Page 4)

4 Warner Electric • 800-825-9050 819-0370
Electrical Connections
To avoid injury (or even death),
always make certain all power is off before
attempting to install or service the control or
any electrical equipment.
Warner Electric Magnetic Particle brakes oper-
ate on DC voltage. Warner Electric offers a full
line of AC powered controls to meet the needs
of almost every application. The service and
installation instructions included with each
Warner Electric control show the proper electri-
cal connections for the brake.
If a varistor is supplied with your unit, it is not
required for use with a Warner Electric control.
All Warner Electric controls have built in sup-
pression.
After wiring your Magnetic Particle brake, check
the control circuit. Without rotating the input
hub, verify that voltage is applied when the con-
trol output is turned on. Also, if appropriate, set
the current for the proper output. Your magnetic
particle unit is now ready for operation. For
information on start up and maintenance, see
below.
Start Up
The powder in the magnetic particle units some-
times settles during shipping and will need to be
redistributed. A simple run in procedure should
be performed to ensure proper performance.
Run in Procedure
Note: Before running in the brake, make sure it
does not bind. See step 2 of the premounting
instructions.
Set the control output voltage to 5 - 6 volts.
Turn off the control and run the input for one
minute. Then run the input at a speed close to,
but not exceeding, 1000 RPM. Cycle the unit at
5 or 6 volts for five seconds on and ten seconds
off. Repeat this for 20 cycles.
When the powder is redistributed properly,
torque will be consistent and proportional to
current.
Maintenance
Heat
If the heat generated during operation is greater
than the heat dissipation capability of the unit, it
will overheat. The maximum allowable surface
temperature for a PRB-H series unit is 194
degrees F.
Slip Applications
The heat generated is proportional to the torque
and slip RPM. Care must be taken when adjust-
ing torque on the control to make sure that the
unit heat dissipation capacity is not exceeded.
Refer to the sizing procedure in the catalog to
make sure the brake has adequate heat dissipa-
tion capability. Also, do not increase the slip
speed or the torque without verifying that the
unit can dissipate the heat.
Cycling Applications
In cycling applications, the speed and inertia of
the load and the stopping frequency determines
the heat generated. Refer to the selection pro-
cedure in the catalog to verify that your brake
can handle the thermal energy generated in your
application. Also, do not increase the speed,
cycle rate, or inertia without checking the unit's
ability to dissipate the heat generated.
Contamination
Do not expose the brake to water or oil. If water
or oil gets in the powder cavity, performance
may be affected. If the brake is mounted next to
a gearbox, special care must be taken to pre-
vent oil from entering the unit.