Warner Electric Primary Brake Pin Drive Armature PB-825, PB-1000, PB-1225, PB-1525 Motor Brake and Spline Drive MB-825, MB-1000, MB-1225 Pin Drive - Manual (Page 10)

10 Warner Electric • 800-825-9050 P-208 • 819-0367
Coil Data
Unit Size PB & MB-825 PB & MB-1000 PB & MB-1225 PB & MB-1525
Voltage — DC 6 24 90 6 24 90 6 24 90 6 24 90
Resistance @ 20°C — Ohms 1.27 20.4 223.3 1.23 19.7 248.7 1.33 22.3 261.7 1.45 19.8 258.4
Current — Amperes 4.74 1.18 .4 4.87 1.22 .36 4.5 1.08 .34 4.13 1.21 .35
Watts 28 28 36 29 29 33 27 26 31 25 29 31
Coil Build-up — Milliseconds 170 170 170 205 220 235 300 320 350 470 490 512
Coil Decay — Milliseconds 70 75 80 70 75 80 190 190 190 200 170 140
Notes: Build-up time equals current to approximately* 90% of steady state value and flux to 90%.
Decay time equals current to approximately* 10% of steady state value and flux to 10%.
*Approximately 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 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, or cycle duty.
If maximum torque is required immediately after
installation, the unit should be burnished by slipping
the friction surfaces together at reduced voltage. It is
recommended that the burnishings 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 voltage should be set at approximately 30% or
50% 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.
Maintenance
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. 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.
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 .001" - .003" below the metal
poles.
Heat: 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.