Electrical Tests. Graco 3A4798F, Pro Xp Waterborne Auto Air Spray Gun

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Electrical Tests. Graco 3A4798F, Pro Xp Waterborne Auto Air Spray Gun | Manualzz

Electrical Tests

Electrical Tests

Electrical components inside the gun affect perfor mance and safety. The following procedures test the condition of the power supply, gun body, charging probe, and electrical continuity between components.

Use megohmmeter Part No. 241079 (AA) and an applied voltage of 500 V. Connect the leads as shown.

Megohmmeter Part No. 241079 (AA-see F IGURE 13) is

not approved for use in a hazardous location. To reduce the risk of sparking, do not use the megohm meter to check electrical grounding unless:

• The gun has been removed from the hazardous location;

• Or all spraying devices in the hazardous location are turned off, ventilation fans in the hazardous location are operating, and there are no flammable vapors in the area (such as open solvent containers or fumes from spraying).

Failure to follow this warning could cause fire, explo sion, and electric shock and result in serious injury and property damage.

Test Total Gun Resistance

1. Flush and dry the fluid passage.

2. Measure the resistance between the charging probe tip (3) and the turbine air inlet fitting (TA). The resistance should be 116–170 megohms for guns with the long charging probe installed. The resis tance should be 101–140 megohms for guns with the short charging probe installed.

3. If outside this range go to Test Gun Resistance with Probe Removed , page 26. If in range, and

there are performance concerns, see

Electrical

Troubleshooting , page 30 for other possible

causes of poor performance.

AA

3

TA

F IG . 13. Test Total Gun Resistance

TA

3A4798F 25

Electrical Tests

Test Gun Resistance with Probe

Removed

Measure the resistance between the turbine air inlet fit ting and the charging probe fitting. The resistance should be 101-140 megohms. If outside this range, check the power supply and barrel resistance. If in range, test the charging probe resistance.

Test Charging Probe Resistance

NOTE: This section only applies to guns with long charging probes.

Measure the resistance between the metal spring in the charging probe (DD) and the charging probe tip (BB).

• For long charging probes, the resistance should be

15–30 megohms.

• For short charging probes, the resistance should be

0 megohms.

If outside this range, replace the charging probe. If in range, inspect the spring and barrel socket for possible causes of poor continuity. Reassemble the charging probe and retest the total gun resistance.

F IG . 14. Test Gun Resistance

F IG . 15. Test Charging Probe Resistance

26 3A4798F

Electrical Tests

Test Power Supply Resistance

1. Remove the power supply (7). See Power Supply

Removal and Replacement , page 38.

2. Remove the turbine (8) from the power supply. See

Turbine Removal and Replacement , page 39.

3. Measure resistance from the power supply's ground strips (EE) to the spring (7a). The resistance should be 86–110 megohms. See F IGURE 16.

If outside this range, replace the power supply. If in range, and there are performance concerns, go to

Test Barrel Resistance , page 27.

4. Refer to

Electrical Troubleshooting , page 30 for

other possible causes of poor performance.

5. Be sure the spring (7a) is in place before reinstalling the power supply.

Test Barrel Resistance

1. Insert a conductive rod (GG) into the gun barrel

(removed for the power supply test) and against the metal contact (HH) in the front of the barrel.

2. Measure the resistance between the conductive rod (GG) and the charging probe socket (CC). The resistance should be 15-30 megohms.

• If the resistance is outside the range, replace the barrel.

• If resistance is in range, reassemble the gun and test the gun resistance.

• If you still have problems, refer to Electrical

Troubleshooting , page 30 for other possible

causes of poor performance.

7a EE

WLD

F IG . 16. Test Power Supply Resistance F

IG

. 17. Test Barrel Resistance

3A4798F 27

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