Manitowoc Grove RT770E, Service Maintenance Manual

Page: 244 / 357

6-20
Published 11/26/2014, Control # 447-05
SWING SYSTEM RT770E
6. Activate all systems, cycle all functions, and observe for
proper operation and any leakage.
ELECTRICAL SWIVEL
Description
The swivel assembly consists of a 20 conductor slip ring and
cover assembly.
Each brush set incorporates two brushes and leads which
are attached to a brush holder assembly. The brush set leads
are formed into harnesses which are routed through the
mounting plate on the swivel. The collector ring leads are
formed into one harness which is routed downward through
the center of the hydraulic swivel. Extending from the base of
the hydraulic swivel, the collector ring leads are also formed
into connectors which plug into receptacles from the chassis
power supply.
The swivel cover is secured with a seal and bolts
The slip ring assembly contains an angle encoder. The
encoder sends data via CAN bus to the RCL. The RCL
converts this data into a slew angle which is used to
determine the working area definition and also for controlling
the rear axle oscillation.
Theory of Operation
The electrical swivel is located on top of the water swivel and
transfers electricity between the carrier and superstructure.
Wiring harnesses transmit the electricity between the carrier
and superstructure.
Maintenance
Removal
1. Perform steps 1 through 4 of HYDRAULIC SWIVEL -
REMOVAL in this section.
2. Disconnect the batteries. Refer to Electrical System ,
page 3-1.
3. Locate the connectors which join the collector ring
harness to the receptacles for the carrier.
4. Tag the connectors and their receptacles with numbers.
Disconnect the connectors from the chassis wiring
receptacles.
NOTE: The connectors are too large to go through the
center of the hydraulic swivel. They must be
removed.
5. Remove the clamp securing the wiring harness to the
retainer plate on the bottom of the hydraulic swivel
assembly.
6. Tag each wire on each of the connectors. Using the
appropriate pin removal tools, remove the pins, with
wires still attached, and mark each wire with the pin
socket number in the connector. Collect the wires and
secure into one bundle. Mark the bundle with the
connector number. For a list of the appropriate pin
removal tools, refer to
Connector Troubleshooting , page
3-8.
7. Secure the connectors and wires from each of the
numbered connectors so the harness can be withdrawn
through the center of the hydraulic swivel.
8. Tag and disconnect the connectors from the receptacles
on the cab bulkhead mounting plate.
9. Loosen the jam nuts and setscrews securing the
electrical swivel mounting tube to the center post on the
water swivel.
10. Remove the bolt and nut securing the electrical swivel
anti-rotation pin to the bracket on the case of the water
swivel.
11. Remove the swivel and wiring harness from the crane. If
necessary, remove the spacer bushing from the center
post.
Installation
1. If removed, install the spacer bushing on the center post.
Route the collector core wiring harness through the
center of the hydraulic and water swivels.
NOTE: The boom should be centered directly over the
front of the crane before adjustment is made to the
slew encoder.
2. Slide the electrical swivel mounting shaft onto the center
post.
CAUTION
Disconnect the batteries before performing any
maintenance on the electrical system. Serious burns may
result from accidental shorting or grounding of live
circuits.
CAUTION
When withdrawing the wiring harness through the center
of the hydraulic and water swivels, ensure the wires do
not get caught and damaged.