8
Application Data
Table 2-1
Data
Slip RPM
Brake Model No.
AS-703
AS-704 AS-705 AS-706 AS-707 AS-708
Maximum Torque
Lb. Ft.
1800
1200
900
53
49
43
110
99
90
210
204
195
420
410
388
-
870
870
-
1740
1740
Dissipation
3600
10
20
Maximum
1800
7.5
15
20
35
60
100
Continuous
1200
5
10
15
25
45
75
Horsepower
900
3.5
7.5
11.5
17.5
34
56
Inertia - Lb. Ft.
0.82
1.64
8.0
16.0
50
100
Size controller
1
2
2
3
3
7
Approximate Shipping
108
205
265
430
1010
1200
Maximum Torque Transmitted Through Shaft
(Standard Brakes Only)
AB-703 - 340 lbs. ft. AB-
704 - 563 lbs. ft. AB-705 -
860 lbs. ft. AB-706 - 1258
lbs. ft. AB-707 - 1749 lbs.
ft. AB-708 - 3103 lbs. ft.
Note - Numbers apply only when there is no
overhung load - consult factory for data with
overhung load.
Typical Brake Cutaway
Figure 2-1
Construction
A single field and rotor type brake as illustrated in
Figure 2-1 is representative of Models AS-703, AS-
705, and AS707. Models AS-704, AS-706
and AB-708 are of the double field and rotor
type which include two rotors, fans and field
assemblies.
Tachometer Generator (optional)
General
The generator is a permanent-magnet, alternating-
current device that produces a linear voltage in
direct proportion to the speed at which it is driven.
In the governing circuit of the control system, the
voltage produced by the generator represents the
actual speed of the unit. This voltage is amplified
and compared with a constant voltage in the
reference circuit, representing the desired speed of
the unit, to effect speed control.
As shown in Figure 2-2, the maximum output speed
of the generator is approximately 55 to 60 volts.
Frequency varies with the speed to a maximum of
500 to 600 Hz. This generator is designed to
operate with equal output and efficiency in either
direction of rotation.
The use of an AC tachometer generator eliminates
rotating windings and consequently no
maintenance of brushes, slip rings, or commutator
is required.
The Alnico magnet employed in this unit (Figure 2-
3) retains its field strength over a long period of
time, assuring a constant generator output at a
given speed. This magnet should not be subjected
to sharp impacts, abuse, or temperatures higher
than the maximum operating temperature of the
unit, as this will result in a weakening of the field
strength. Should removal of
