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Tech-Tip 93 

Released: 6/19/2019 

Tech Tips 

Service Call: 

AC Dielectric Testing of a Category C 

Telescopic Aerial Device 

  

Tools Required: 

 AC Dielectric Tester 

 Insulating Outrigger Pads 

 Safety equipment to create a 

dielectric test area 

 

Model(s): 

L13I, L17I, TL  

 

 

 

 

 

 

 

 

 

 

 

 

Summary of Contents for L13I

Page 1: ...9 2019 Tech Tips Service Call AC Dielectric Testing of a Category C Telescopic Aerial Device Tools Required AC Dielectric Tester Insulating Outrigger Pads Safety equipment to create a dielectric test...

Page 2: ...epair procedures are performed Do Not Perform Maintenance Unless You are trained and qualified to perform maintenance on this machine You read understand and obey o manufacturer s instructions and saf...

Page 3: ...anyone unassociated with the procedure out of the testing area If a barrier is not available use a spotter s The AC Dielectric Tester voltage source should also be contained within this area The test...

Page 4: ...er the unit is insulated or non insulated If the unit is insulated the qualification voltage and rating of the unit will be shown Verify that the boom is designed as insulated before proceeding with t...

Page 5: ...for any bird s nests material buildup or hydraulic leaks in the boom or control areas Check under the boom tip covers and look down each boom from both ends checking for a blockage or any signs of a l...

Page 6: ...lace the transmission in neutral and turn on the PTO Set the unit up for operation by deploying the outriggers onto insulating platforms pads centered under the outrigger foot reference Figure 1 Once...

Page 7: ...om 5 Platform bracket to boom tip bracket 6 Jib bracket if equipped to platform bracket 7 Verify that the jumpers make good contact by removing paint if needed at the attachment location prior to atta...

Page 8: ...Tech Tip 93 8 Released 6 19 2019 Tech Tips Figure 2...

Page 9: ...he boom tip This may be attached at the same location as the jumpers that were installed at the boom tip See Figure 3 Keep the test machine directly below or away from the truck if possible Follow the...

Page 10: ...e lower and upper booms both at 45 degrees Extend the upper boom to the minimum extension decal if equipped Visually check that all jumpers voltage source from the AC Dielectric Tester and return are...

Page 11: ...l connections If the current meter value stays below the Max Leakage continue the test until complete record readings return the voltage control to 0 turn off and unplug the dielectric machine If the...

Page 12: ...or after a major component such as a boom is replaced Periodic testing is done once a year to verify dielectric integrity of the unit For a Category C AC Qualification test the reading should be no hi...

Page 13: ...below rotation 1 Lower boom insert 3 Upper boom to knuckle 4 Knuckle to lower boom 5 Platform bracket to boom tip bracket 6 Jib bracket if equipped to platform bracket 7 See Figure 2 to identify jumpe...

Page 14: ...lectric Tester to the knuckle side of the lower boom and install jumpers between components in the following locations as shown in Figure 4 below Lower boom to knuckle 1 Lower boom link to knuckle 2 T...

Page 15: ...heet Monitor the volt and current meters to verify that the test is working correctly If the current meter value stays below the Max Leakage continue test until complete record readings return the vol...

Page 16: ...below For a Chassis Insulating System Lower Boom Insert Qualification test the reading should be no higher than 3000 A for 3 minutes at 50 KV For a Chassis Insulating System Lower Boom Insert Periodi...

Page 17: ...from the following locations indicated in Figure 4 Lower boom to knuckle 1 Lower boom link to knuckle 2 Turntable above rotation to pedestal below rotation 3 Lower boom link to turntable 4 Remove the...

Page 18: ...Tip 93 18 Released 6 19 2019 Tech Tips Step 15 Attach the voltage source from the AC Dielectric Tester to the control handle using a spring with the cable going over the top of the platform as shown b...

Page 19: ...19 Released 6 19 2019 Tech Tips Step 16 Reach under the upper control cover and attach the current meter return to a fitting that is attached to the upper control valve as shown below Cover removed f...

Page 20: ...listed on the test sheet Monitor the volt and current meters to verify that the test is working correctly If the current meter value stays below the Max Leakage continue the test until it is complete...

Page 21: ...hould be no higher than 400 A for 3 minutes at 40 KV A Microamp Step 19 Once testing is complete lower the platform to the ground mount position Remove the spring from the control handle and current m...

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