Danfoss Airflex DBBS, Installation, Operation And Maintenance Manual

Page: 9 / 27

Airflex ® DBB 8110 Brake Assembly E-CLCL-TT001-E December 2012 9
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.
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.
TABLE 5
Maximum Disc Speeds
Size Max. Free
Wheeling Speed RPM
20DBBS 2200
25DBBS 1700
38DBBS 950
50DBBS 600
TABLE 6
DBBS Wear-in Parameters
Maximum
Free Maximum Standard
Slip Brake Wheeling Maximum Temp at Wear-in Quantity Power Brake Torque
Brake Number of Speed Pressure Slip Time Speed Temp at Start End of Slip Cycles of Power Target Target
Size Discs (rpm) psi (bar (sec) (rpm) of Slip °F (°C) °F (°C) Required Springs HP (Kw) in-lb (N-m)
1 29 (22) 15318 (1 730)
20DBBS
2
120 60 (4.1) 60 2,200 120 (49) 250 (121) 15 18
58 (44) 30636 (3461)
3 87 (65) 45954 (5192)
4 116 (8 7) 612 72 (6923)
1 52 (39) 27450 (3101)
25DBBS
2
120 65 (4.5) 60 1, 700 120 (49) 250 (121) 15 24
104 ( 78) 54900 (6202)
3 156 (11 7) 82350 (9304)
4 208 (156) 109800 (12405)
1 116 (8 7) 121848 (13 766)
38DBBS
2
60 60 (4.1) 60 950 120 (49) 250 (121) 15 48
231 (1 73) 242646 (2 7415)
3 347 (259) 364495 (41182)
4 463 (346) 486343 (54949)
1 169 (120) 178000 (20111)
50DBBS
2 338 (252) 356000 (40222)
3
60 88 (6.1) 60 600 120 (49) 250 (121) 15 112
507 (378) 534000 (60333)
4 676 (504) 712000 (80445)
DBBS Brakes