The Motor Works on the Bench.  
But What Happens Under Load?
Why load testing a repaired hydraulic motor before it returns to work matters.
Hydraulic pumps are tested after 
overhaul, so why not motors? A hydraulic 
motor can be rebuilt correctly, pass 
inspection and run successfully on a 
workshop test bench. But there is a 
bigger question to answer: how will it 
perform when it is back on the machine 
and working under load?
For applications on heavy machinery, 
that question matters. If a problem 
only materialises after the motor has 
been refitted, the consequences can be 
severe, creating additional labour, further 
downtime and the cost and disruption of 
removing and refitting the motor.
With its new testing facility ‘The Rig’, 
Plant Parts has added another layer 
of validation before a repaired motor 
is returned to work. Representing 
an investment of around £1 million, 
this dedicated hydraulic motor load-
testing facility has been designed to 
accommodate most types of hydraulic 
motors. This allows repaired units to be 
tested under controlled load conditions 
with performance measured against 
manufacturers’ standards before leaving 
the workshop.
A new testing facility in Suffolk
Traditional workshop testing remains 
an important part of the repair process 
for simple or non-critical applications, 
but confirming that a motor will turn 
does not necessarily show how it will 
perform when subjected to the demands 
of working machinery. The Rig applies 
a consistent, predefined and controlled 
series of tests on each motor while 
capturing performance data throughout.
 
Plant Parts has integrated this load 
testing as part of the motor repair service 
for critical applications, rather than 
treating it as a premium additional option.
How it works
The Rig uses a forced-air-cooled 
dynamometer with bespoke regenerative 
technology and an electronic drive system 
to create controlled operating conditions 
while capturing performance information 
throughout the test. 
The facility has been designed to 
accommodate hydraulic motors from 18 
cc to 340 cc, with dynamic load testing 
from 0–3,000 rpm available up to 132 kW 
and static load testing beyond that. It can 
also measure two-speed change and auto 
kick-down pressure, mechanical brake 
torque, brake time delay and hydraulic 
braking with simulated inertia. It applies 
continuous data logging to produce a full 
performance report. It records how the 
motor has performed before it is returned 
to the machine.
“If you’ve ever had to remove 
and refit a hydraulic motor, you’ll 
know it’s not always a five-minute 
job. The last thing you want 
is to go through all that work, 
only to find there’s a problem 
once it’s back on the machine. 
Being able to test the motor 
under load before it leaves our 
workshop gives our customers 
and our technicians a bit more 
reassurance that it’s ready to go 
back to work.”
Dave Finch, Business Development 
Manager, Plant Parts 
 
What this means for equipment operators 
 
Load testing provides operators 
and machine owners with recorded 
performance data for their repaired motor 
before it returns to work.
For Plant Parts, this is the practical 
purpose behind The Rig. The investment 
is not simply about introducing new 
technology into the workshop; it is 
about using load testing and recorded 
performance information to support the 
repair process.
As machinery becomes more 
sophisticated and the cost of downtime 
continues to rise, the ability to gather 
and record meaningful data before 
a component returns to work is 
increasingly valuable.
Contact here:
+44 1473 820910
sales@plant-parts.com
www.plantparts.com
Members of the Plant Parts team
The new testing facility is in Suffolk, UK
The dedicated hydraulic 
motor load-testing facility
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