Nexen SPC 837400 - Manual (Page 10)

10 FORM NO. L-20095-U-1112
Figure 9
SPRING ENGAGED-DUAL AIR MODE
This mode allows the selection of any value of spring
engaged torque (from zero to full scale) available with a
particular disc size by relieving a percentage of the minimum
Hold-Off pressure 5.2 bar [75 psi]. The remaining pressure,
balanced against the spring force, reduces the output of
the Actuator (See Figure 10).
EXAMPLE: A standard spring set brake with a 24 inch
disc has a full rated spring engaged torque of 3,360 Nm
[30,000 in-lb] when using the minimum hold-off pressure of
75 psi [5.2 bar]. If it is desired to have 60% of this torque
or 2,016 Nm [18,000 in-lb], relieve the hold-off pressure
60 percent or 3.1 bar [45 psi], leaving 2.1 bar [30 psi]
hold-off pressure.
Figure 10
3-Way Control N.C.
Filter
Lubricator
3-Way Manual
Control
Air Supply
Regulator
Power
Source
3-Way Manual
Control
Air Supply
Regulator
Power Source
3-Way Control N.C.
Power Source
Regulator
3-Way Control
N.C.
Lubricator
Filter