BRADEN CH400B Installation Maintenance And Service Manual page 15

TROUBLE
C
The brake will not hold a
load with the control lever
in neutral.
D
The hoist will not hoist the
rated load.
PROBABLE CAUSE
1. Excessive system back pressure acting
on the brake release port.
2. Friction brake will not hold due to worn
or damaged brake discs.
3. Brake clutch is slipping.
1. The hoist may be mounted on an un-
even or flexible surface which causes
distortion of the hoist base and binding
of the gear train. Binding in the gear
train will absorb horsepower needed to
hoist the rated load and cause heat.
2. System relief valve may be set too low.
Relief valve needs adjustment or re-
pair.
3. Be certain hydraulic system tempera-
ture is not more than 180°F (82°C).
Excessive hydraulic oil temperatures
increase motor internal leakage and re-
duce motor performance.
4. Hoist line pull rating is based on 1st lay-
er of wire rope.
5. Rigging and sheaves not operating ef-
ficiently.
Same as remedy for Trouble B2.
Same as remedy for Trouble A2.
Improper planetary gear oil may cause the
brake clutch to slip. Drain old gear oil and
flush hoist with solvent. Thoroughly drain
solvent and refill hoist with recommended
planetary gear oil listed in "Preventive Main-
tenance."
Brake clutch may be damaged or worn. Dis-
assemble and inspect brake clutch as de-
scribed in "Brake Clutch Service."
Reinforce mounting surface.
If necessary, use shim stock to level hoist.
Refer to "Hoist Installation."
First loosen, then evenly retighten all hoist
mounting bolts to recommended torque.
Check relief pressure as follows:
A. Install an accurate 0-4000 PSI (28,000
kPa) gauge into the inlet port of the brake
valve.
B. Apply a stall pull load on the hoist while
monitoring pressure.
C. Compare gauge reading to hoist specifi-
cations. Adjust relief valve as required.
NOTE: If pressure does not increase in pro-
portion to adjustment, relief valve may be
contaminated or worn out. In either case,
the relief valve may require disassembly or
replacement.
Same as remedies for Trouble D1 and D2.
Same as remedies for Trouble E2.
Refer to hoist performance charts for addi-
tional information.
Perform rigging service as recommended by
crane manufacturer.
15
REMEDY