Terex L13I User manual

Tech-Tip 93 1 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

Tech-Tip 93 2 Released: 6/19/2019
Tech Tips
Tech Tip Safety Rules
Danger
Failure to obey the instructions and safety rules in the appropriate
Operator's Manual and Service Manual for your machine will result in
death or serious injury. Many of the hazards identified in the operator’s
manual are also safety hazards when maintenance and repair
procedures are performed.
Do Not Perform Maintenance Unless:
•You are trained and qualified to perform maintenance on this
machine.
•You read, understand and obey:
omanufacturer’s instructions and safety rules
oemployer’s safety rules and worksite regulations
oapplicable governmental regulations
•You have the appropriate tools, lifting equipment and a suitable
workshop.
The information contained in this tech tip is a supplement to the service
manual. Consult the appropriate service manual of your machine for
safety rules and hazards.

Tech-Tip 93 3 Released: 6/19/2019
Tech Tips
Step 1
In the interest of safety, the dielectric testing
area should be separated from the normal work
area by means of a barrier to keep 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 area must be free of any obstructions
both on the ground and above/around the unit.
The boom must not be near any trees, buildings
or energized power lines when elevated for
testing.

Tech-Tip 93 4 Released: 6/19/2019
Tech Tips
Consult the ID Placard to determine whether 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 the dielectric test.
Insulated/
Non-Insulated
Insulating
Category
Qualification
Voltage

Tech-Tip 93 5 Released: 6/19/2019
Tech Tips
Step 2
Complete a thorough daily inspection of the unit,
including running all boom functions through
their full range of motion before beginning any
dielectric testing. Daily inspection criteria can be
found in the unit specific operators and
maintenance manuals.
The fiberglass booms must be clean, dry and in
good physical condition. Check carefully 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 leak. A bird’s nest, blockage, or leak in the
boom could ignite and cause a fire during the
dielectric test.
If a blockage or leak is found it must be repaired
and the unit cleaned prior to continuing with the
dielectric test.
Record all unit info and weather conditions on
the dielectric test sheet prior to starting the test.
The test sheets are included in the Manual and
can be copied as needed.

Tech-Tip 93 6 Released: 6/19/2019
Tech Tips
Step 3
Drive the unit into the dielectric testing area and
onto the insulating platforms (pads) centered
under the tires. Engage the park brake, place
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 outrigger setup is complete, shift
the outrigger/unit selector into the unit position.
The boom can be brought to the ground mount
position to aid in set-up during the next steps.
Figure 1

Tech-Tip 93 7 Released: 6/19/2019
Tech Tips
Step 4
To begin setup for testing the upper boom,
install jumpers between components in the
following locations as shown in Figure 2:
•Turntable above rotation to pedestal below
rotation (#1)
•Turntable above rotation to lower boom (#2)
•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)
Verify that the jumpers make good contact by
removing paint, if needed, at the attachment
location prior to attaching the jumpers. Some
units are equipped with stainless bolts
specifically for dielectric testing, use these if
equipped.
The jumpers and connections are shown in RED
in the following Figures. They do not reflect the
actual connection points where the jumpers are
installed on the unit, but are only a reference to
the general location.

Tech-Tip 93 8 Released: 6/19/2019
Tech Tips
Figure 2

Tech-Tip 93 9 Released: 6/19/2019
Tech Tips
Step 5
Attach the current meter return to the back of the
truck. If a ground lug or loop is available, attach
the return there.
Attach the voltage source from the AC Dielectric
Tester to the 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 instructions of the dielectric testing
machine for any further connections that are
required. Verify that the dielectric tester has
been grounded.
The dielectric tester controls should be located outside the
dielectric test area.

Tech-Tip 93 10 Released: 6/19/2019
Tech Tips
Step 6
Position the 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 still
connected once unit is in position. See Figure 3.
Figure 3