Warner Electric General Trouble Shooting - Manual (Page 6)

6 Warner Electric • 800-825-9050 P-233 • 819-0451
Environmental Problems
If units are used on machinery where fine, abrasive
dust, chips or grit are dispelled into the atmosphere,
shielding the clutch may be necessary if maximum
life is to be obtained. Where units are used near
gear boxes or transmissions requiring frequent
lubrication, means should be provided to protect
friction surfaces from oil and grease to prevent
serious loss of torque.
Wear Pattern
Wear grooves appear on the armature and
magnet surfaces. This is a normal wear condition
and does not impair functioning of the unit.
Remachining Faces
Remachining the face of a worn armature is not
recommended. If a replacement armature is to be
used with a used magnet, it is necessary to
remachine the worn magnet face. In refacing a
magnet: (1) machine only enough material to clean
up the complete face of the magnet; (2) hold the
face within .005" of parallel with the mounting
plate; and (3) undercut the molded facing material
.002" - .004" below the metal poles. Normally the
magnet and armature, as a mating pair, will wear
at the same rate. It is the usual recommendation
that both components be replaced at the same
time.
Burnishing
Intimate metal to metal contact is essential
between the armature and the metal rings
(called poles) of the magnet. Warner Electric
clutches and brakes leave the factor with the
friction material slightly undercut to assure a
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 or cycle duty. If maximum torque
is required immediately after installation, the unit
should be burnished by forcing the friction
surfaces to slip at reduced voltage. It is
recommended that the burnishing be done right
on the installation, if at all possible. Burnishing at
high speed will result in a smoother wear-in
pattern and reduce the time for burnishing.
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.
Heat Dissipation
Excessive heat and high operating temperatures
are causes of rapid wear. Units, therefore,
should be ventilated as efficiently as possible,
especially if the application requires fast,
repetitive cycle operation.
The wear grooves in the armature face result
from a normal wearing-in process.
Oil and grease accidentally reaching the friction
surfaces may be removed by wiping with a rag
dampened with a degreasing solvent. In
performing this operation, do not drench the
friction material. If the friction materials have been
saturated with oil or grease, no amount of
cleaning will be completely effective. Once such a
unit has been placed back in service, heat will
cause the oil to boil to the surface, resulting in
further torque loss.
New
Burnished
Worn