18
Bulletin HY22-3220A/US
Instruction Manual
550 Series Hydraulic Power Units
FAILURE MODE
CAUSE(S)
CORRECTIVE ACTION
Dirty fluid
Filler/breather cap not installed on reservoir
Install the proper filler/breather cap on the reservoir.
Drain dirty fluid and replace with clean fluid
Fluid lines not properly covered while servicing
power unit
Once service is complete and all lines are properly
connected, drain dirty fluid and replace with clean fluid
Pump strainer is plugged, damaged or missing
Install a new pump suction strainer
Foaming fluid
Fluid line is broken allowing air into system
Locate and replace broken fluid lines. Allow air in fluid to
settle out before operating system
Fluid contaminated with foreign matter
Eliminate source of foreign matter, drain dirty fluid and
replace with clean fluid
System overheats
Power unit runs at relief valve setting for
extended period of time
Install switches or load holding valve as needed to
prevent the pump from running over the relief valve for
extended period of time
Reservoir sized too small
Contact your Parker Oildyne distributor for a larger
reservoir
Fluid conductors are too small for system flow
rates
Increase the fluid conductor sizes to reduce fluid
velocities
Foreign matter sources in
system
Sealing compound (pipe dope, TeflonTM tape,
etc.) allowed inside fittings
Use a reduced amount of sealing compound to ensure it
doesn’t overflow into wetted areas
System pressure exceeds design limits of seals
and gaskets
Either reduce the operating pressure or select
components capable of the high pressures
Human element – components not protected
during service
During service, ensure all components are protected
from external contamination
Solenoid coil failures
Voltage too low
Voltage to solenoids must be per solenoid specification
to avoid burning out coil
Voltage too high
Voltage to solenoids must be per solenoid specification
to avoid burning out coil
Both solenoids are energized concurrently
Only one solenoid can be energized at any given time
to prevent coil burnout. Ensure voltage signals are
interlocked to prevent this condition
Mechanical damage to leads
Replace all damaged wires and/or plugs
Voltage signal loss
Long leads can cause improper voltage signal at coils
and erratic signal. Check with voltmeter
Troubleshooting
Appendix
56C Adapter Kit, part number 775679, Installation
using Customer-supplied Motor
Installing customer-supplied motor using 56C Adapter Kit
This is easiest with the 550 Series Power Unit sitting vertically
on a table with the reservoir down.
1. Tighten the tapered ends of the four studs into the motor face
threaded holes until bottomed out. These are interference fit
studs so resistance is expected.
2. Install the shaft adapter onto the motor’s keyed shaft with the
set screw positioned over the keyway. With the shaft adapter
pushed all the way onto the motor shaft, tighten the set screw
to 3.4 to 4.5 Nm (30 to 40 in-lbs) torque using a 5/64 in Allen
wrench.
3. Take the coupling that came with the power unit and liberally
fill both slots with a heavy, axle-type, grease.
4. Insert the coupling into the power unit adapter so the pump
shaft tang engages the female slot fully.
5. Position the 56C adapter plate on the 550 Series Power Unit
adapter so the four through holes align with the four through
holes in the power unit adapter.
6. Turn the motor shaft so the tang on the shaft adapter will align
with the up-facing coupling slot, then carefully lower the electric
motor vertically onto the power unit/56C adapter plate so the
four studs pass through the four through holes. If the motor
face, the 56C adapter plate and the 550 Series Power Unit
adapter are not tight together, reposition the motor shaft until it
aligns with, and mounts into, the coupling slot.
7. Turn the four nuts onto the four studs until all are finger tight,
then torque the four nuts to 20 +/- .5 Nm (180 +/- 5 in-lbs).
Installation is now complete. Follow the start up instructions on
page 10.
SHAFT ADAPTER
& SET SCREW
CUSTOMER'S MOTOR
56C ADAPTER PLATE
550 SERIES
POWER UNIT
ADAPTER
NUTS (4)
STUDS (4)
Parker Hannifin
HPS Division
New Hope, MN 55428 USA
