Operation; Pressure And Speed Limits; Initial Operation - Danfoss Airflex DBBS Installation, Operation And Maintenance Manual

DBBS Brakes
3.0

Operation

3.1

Pressure and Speed Limits

3.1.1 Maximum allowable pressure is 120 psig (8.2 bar)
for sizes 20DBBS, 25DBBS and 38DBBS. Maximum
allowable air pressure is 150 psig (10.3 bar) for the
50DBBS.
Warning
Maximum applied pressure is 120 psig (8.2 bar) for
sizes 20DBBS, 25DBBS and 38DBBS. Maximum
allowable air pressure is 150 psig (10.3 bar) for
the 50DBBS. Operation at pressures exceeding
maximum may result in damage to the DBBS
components.
3.1.2 Maximum freewheeling disc speeds are shown on
Table 5.
Warning
Operation at disc speeds exceeding the maximum
allowable, as shown on Table 5, may result in
personal injury or product/equipment damage.
TABLE 6
DBBS Wear-in Parameters
Slip
Brake Number of Speed
Size Discs (rpm)
1
2
20DBBS 120
3
4
1
2
25DBBS 120
3
4
1
2
38DBBS 60
3
4
1
2
50DBBS
3
60
4
Maximum
Free
Brake Wheeling
Pressure Slip Time Speed
psi (bar (sec) (rpm)
60 (4.1) 60 2,200
65 (4.5) 60 1, 700
60 (4.1) 60 950
88 (6.1) 60 600
TABLE 5
Maximum Disc Speeds
Size
20DBBS
25DBBS
38DBBS
50DBBS
3.2

Initial Operation

3.2.1 Wear-in/Burnishing
3.2.1.1 In order to improve initial operation and brake torque,
it is suggested that the non-asbestos friction material
used in the DBBS brakes be worn-in prior to normal
operation to improve contact of the mating friction
surfaces.
Caution
Machine operation should be monitored closely until
the friction couple wears in.
3.2.1.2 The shaft on which the brake discs are mounted
should be free to rotate to allow for run-in. On
drawworks applications, disconnect the wire rope
from the drawworks drum to allow operation as
described in the following paragraphs.
Maximum
Maximum Temp at Wear-in
Temp at Start End of Slip Cycles
of Slip °F (°C) °F (°C) Required
120 (49) 250 (121) 15
120 (49) 250 (121) 15
120 (49) 250 (121) 15
120 (49) 250 (121) 15
Airflex DBB 8110 Brake Assembly
®
Max. Free
Wheeling Speed RPM
2200
1700
950
600
Standard
Quantity Power Brake Torque
of Power Target Target
Springs HP (Kw) in-lb (N-m)
29 (22)
58 (44)
18
87 (65)
116 (8 7)
52 (39)
104 ( 78)
24
156 (11 7) 82350 (9304)
208 (156)
116 (8 7)
231 (1 73)
48
347 (259)
463 (346)
169 (120)
338 (252)
507 (3 78)
112
676 (504)
E-CLCL-TT001-E December 2012
15318 (1 730)
30636 (3461)
45954 (5192)
612 72 (6923)
2 7450 (3101)
54900 (6202)
109800 (12405)
121848 (13 766)
242646 (2 7415)
364495 (41182)
486343 (54949)
1 78000 (20111)
356000 (40222)
534000 (60333)
712000 (80445)
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