Jacobsen AR3, Техническое руководство по ремонту

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HYDROSTATIC POWER TRAIN
4181384 First Edition 5-11
5
Instrument Test Procedures
Instrument Test Overview
The following tests are specifically designed to approach
hydraulic testing on a system level. Each component
within the system represents a portion of the total system
leakage. An internal leakage percentage for each
component will be calculated and recorded, enabling the
technician to view the system performance issue more
completely. The test results will help the technician to
decide which repairs will best remedy the performance
issue experienced by the machine user.
The internal leakage percentage ranges are as follows:
0—10% = Good
11—20% = Marginal
21% and beyond = Bad
Example: Traction System Performance Complaint
The machine operator reports the machine struggles to
climb hills.
A charge pressure test must first be performed to rule out
a charge pump issue. Next, the entire traction system is
tested as outlined, and the calculated system leakage is
31%; a result which requires the testing of individual
components. This result can also be interpreted as the
system is 69% efficient.
The remaining components in question are as follows:
traction pump, left front wheel motor, right front wheel
motor, and rear wheel motor. Following the procedures
as outlined, test each individual component, then
calculate and record leakage percentages.
The results from this test reveal leakage of 5% in the
traction pump, 20% in the left front wheel motor, 5.3% in
the right front wheel motor, and 4.1% in the rear wheel
motor. Although all the components lend to the overall
system leakage, only the left front wheel motor, which is
at the extreme end of the marginal range, would be
considered for repair/replacement.
Formulas:
Wheel Motor
Loaded Flow from previous component - Loaded Flow
from current component / Loaded Flow from previous
component x 100 = Leak Percentage
System and Traction Pump
No Load Flow - Loaded Flow / No Load Flow x 100 =
Leak Percentage
Calculations:
System Test
No Load Flow = 10 gpm
Loaded Flow = 6.9 gpm
10 - 6.9 / 10 x 100 = Total System Leakage 31%
Traction Pump Test
No Load Flow = 10 gpm
Loaded Flow = 9.5 gpm
10 - 9.5 / 10 x 100 = Traction Pump Leakage 5%
Left Front Wheel Motor Test
Loaded Flow from traction pump test = 9.5 gpm
Loaded Flow from left front wheel motor test = 7.6 gpm
9.5 - 7.6 / 9.5 x 100 = Left Wheel Motor Leakage 20%
Right Front Wheel Motor Test
Loaded Flow from left front wheel motor test = 7.6 gpm
Loaded Flow from right front wheel motor test = 7.2 gpm
7.6 - 7.2 / 7.6 x 100 = Right Wheel Motor Leakage 5.3%
Rear Wheel Motor Test
Loaded Flow from right front wheel motor test = 7.2 gpm
Loaded Flow from rear wheel motor test = 6.9 gpm
7.2 - 6.9 / 7.2 x 100 = Rear Wheel Motor Leakage = 4.1%
Charge Pressure Test
See Figures 5-7 and 5-8.
!
WARNING
1. Operate hydraulic system until oil temperature is at
120—150°F (49—65°C).
2. Park the mower safely. (See “Park Mower Safely” on
page 1-7.)
3. Raise the hood and seat.
The hydraulic system is under pressure, and the
oil will be hot.
• Always relieve pressure in the hydraulic
system before performing service.
• Failure to follow appropriate safety
precautions may result in death or serious
injury.
Required Tools and Materials
• Pressure Gauge 500 psi (35 bar)
• Test Hose 500 psi (35 bar)