797F Off-Highway Truck: Gear Pump (Hoist and Brake Cooling) Flow - Test & Position Sensor (Truck Body) - Adjust

1.-Gear Pump (Hoist and Brake Cooling) Flow - Test

This test is designed to determine if a pump is operating within the designed parameters.

For any pump test at a given rpm, the pump flow at 690 kPa (100 psi) will be larger than the pump flow at 6900 kPa (1000 psi).

The difference between the pump flow of the two operating pressures is the flow loss.

Flow loss is used as a measure of pump performance when the flow loss is expressed as a percent of pump flow.

Table 1

Percent of flow loss
[(A - B) ÷ C] × 100 = D
A	Pump flow at 690 kPa (100 psi)
B	Pump flow at 6900 kPa (1000 psi)
C	Pump flow at 690 kPa (100 psi)
D	Percent flow loss

Table 2

Example
[(A - B) ÷ C] × 100 = D
A	217.6 L/min (57.5 US gpm)
B	196.8 L/min (52.0 US gpm)
C	217.6 L/min (57.5 US gpm)
D	Percent of flow loss
[(217.6 L/min (57.5 US gpm) - 196.8 L/min (52. US gpm)) ÷ 217.6 L/min (57.5 US gpm)] × 100 = D
	D = 9.6 percent

If the percent of loss is more than 10 percent for the machine test or 15 percent for the bench test, the pump performance is not good enough.

Note: The numbers in the formula are only examples. These numbers are not values for any particular pump nor for any particular pump condition. See the Hydraulic System Specifications, "Gear Pump (Hoist and Brake Cooling)" for the pump flow of a new pump at 690 kPa (100 psi) and at 6900 kPa (1000 psi).

Bench Test

If the bench test can be run at 6900 kPa (1000 psi) and at full rpm, determine the percent flow loss.

If the bench test cannot be run at 6900 kPa (1000 psi) and at full rpm, use the following procedure:

1. Run the pump shaft at 1000 rpm.

2. Measure the pump flow at 690 kPa (100 psi) and 6900 kPa (1000 psi).

3. Use the measurements from Step 2 for the values of A and B in Table 1.

4. To determine the value of C, use Steps 4.a through 4.b.
   
   
   1. Run the pump shaft at 2000 rpm.
   
   
   2. Measure the pump flow at 690 kPa (100 psi).

5. Use the measurement from Step 4.b for the value of C in Table 1.

2.-Position Sensor (Truck Body) - Adjust

(1) Rod end (2) Nut(3) Rod

Note: The position sensor for the truck body must be correctly adjusted for the proper operation of the gear limit when the truck body is raised. Also, the position sensor for the truck body is used to control the SNUB position of the hoist control valve.

The distance between the centers of the rod ends must be 423 ± 3 mm (16.7 ± 0.1 inch).

Rod Adjustment

1. Disconnect rod (3) from the truck body.

2. Loosen nut (2) on rod (3) .

3. Adjust rod end (1) in order to get a distance of 423 ± 3 mm (16.7 ± 0.1 inch) between the centers of the rod ends.

4. Tighten nut (2) .

5. Reattach rod (3) to the truck body.

MARYGAR

797F Off-Highway Truck: Gear Pump (Hoist and Brake Cooling) Flow - Test & Position Sensor (Truck Body) - Adjust 2012-12-04T17:10:00-08:00 Rating: 4.5 Diposkan Oleh: Unknown