Warner Electric SFC-1525 User Manual
Page 6
6
Warner Electric • 800-825-9050
P-207
•
819-0516
Maintenance
Wear Pattern: Wear grooves appear on the armature
and rotor surfaces. This is a normal wear condition, and
does not impair functioning of the unit. Normally, the
rotor 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.
Remachining the face of a worn armature is not
rec om mend ed. If a replacement armature is to be used
with a used rotor, it is necessary to remachine the worn
rotorface. In refacing a rotor: (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.
Heat: Excessive heat and high operating temperatures
are causes of rapid wear. Units therefore, should be
ven ti lat ed as efficiently as possible, especially if the
ap pli ca tion requires fast, repetitive cycle operation.
Foreign Materials: If units are used on machinery
where fine, abrasive dust, chips or grit are dispelled into
the at mo sphere, shielding of the brake or clutch may be
nec es sary if maximum life is to be obtained.
Electrical Coil Data
Unit Size
SF-825
SF-825 Brg.
SF-1000
Voltage–DC
6
24
90
6
24
90
6
24
90
Resistance @ 20°C–Ohms
1.23
20.9 267.0
1.098
14.6
221
1.07
14.4 214.4
Current–Amperes
4.9
1.15
.34
5.464
1.65
.407
5.61
1.67
.42
Watts
29
28
30
33
40
37
34
40
38
Coil Build-Up–Milliseconds
222
200
245
180
200
225
256
275
283
Coil decay–Milliseconds
105
120
100
115
120
130
123
105
90
Unit Size
SF-1225
SF-1525 SF-1525 HT
Voltage – DC
6
24
90
6
24
90
6
24
90
Resistance @ 20°C–Ohms
1.21
19.5 268.3
1.11
15.5
239.1
.55
7.63 113.4
Current – Amperes
4.97
1.23
.34
5.41
1.55
.38
10.83
3.14
.794
Watts
30
30
30
32
37
34
65
75
72
Coil Build-Up – Milliseconds
475
440
510
505
535
575
480
535
560
Coil decay–Milliseconds
240
230
220
230
237
215
210
183
160
Notes: Build-up time equals current to approx.* 90% of steady state value and flux to 90%
Decay time equals current to approx.* 10% of steady state value and flux to 10%.
*Approx. because current leads or lags flux by a small amount.
Burnishing and Maintenance
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
fac to ry with the friction material slightly undercut to
assure good initial contact.
Normally, the desired wearing-in process occurs nat u ral ly
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
in stal la tion, the unit should be burnished by slipping
the friction surfaces together at reduced voltage. It is
rec om mend ed 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 burnishing. The volt age
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
as sem bled and installed, no further servicing, lubrication,
or maintenance should be required throughout the life of
the unit.