Warner Electric Electro-Module EM-50, EM-100, EM-180, EM-210, EM-215 - Manual (Page 9)

9 Warner Electric • 800-825-9050 P-213 • 819-0303
Section I: Burnishing
Intimate metal to metal contact is essential
between the armature and the metal rings (poles)
of the magnet or rotor. Warner Electric clutches
and brakes leave the factory with the friction
material slightly undercut to assure good initial
contact.
Normally, the desired wearing-in process occurs
naturally as the surfaces slip upon engagement.
The time for wear-in, which is necessary to
obtain the ultimate torque of the unit, will vary
depending on speed, load, and duty cycle.
If maximum torque is required immediately after
installation, the unit should be burnished by slip-
ping the friction surfaces together at reduced
voltage. It is recommended that the burnishing
be done right on the application, if at all possible.
Burnishing at high speed will result in a smoother
wear-in pattern and reduce the time for burnish-
ing. The voltage should be set at approximately
30% or 40% of the rated value.
The unit should be cycled on and off to allow
sufficient time between slip cycles to prevent
overheating.
When a Warner Electric brake or clutch is
properly assembled and installed, no further
servicing, lubrication, or maintenance should
be required throughout the life of the unit.
Troubleshooting
If an Electro-Module fails to engage, there are
several possible causes. These can be broken
down into two sub-headings: Electrical and
Mechanical.
Electrical - If a clutch or brake or clutch/brake
will not engage, review the wiring, switching and
connections.
A. Visually inspect to ensure that the lead wires
are not split or cut.
B. Using a voltmeter confirms that DC voltage is
reaching the lead wires when it should be
and that the coil resistance is correct.
Mechanical - A likely mechanical cause for a
clutch or brake not engaging when DC power is
applied is that the airgap between the friction
faces is too large. When power is applied to an
Electro-magnetic clutch/brake, the unit magneti-
cally clamps the friction faces together. An air-
gap that is too large can keep the unit from
clamping together. If the airgap is too small the
faces will rub all of the time.
To adjust the airgap, see Section C on page 5.
Maintenance
As with any friction-type device, some initial
concern should be given to wear rate, as minor
adjustments in actuation time can sometimes
extend the life of the unit.
For clutch modules, the control potentiometer
should be set high to reduce the actuation time.
For brakes, the setting can be reduced to
extend the braking time and thereby extend the
life. Once the best actuation time has been
established, precautions should be taken to pre-
vent machine operators, or other personnel not
familiar with wear characteristics, from changing
the potentiometer setting arbitrarily for affecting
minor operating changes.