T90 speed sensor operation
An optional speed sensor can provide unit speed information. The sensor reads a magnetic ring on the
unit’s cylinder block. See the corresponding section to locate, install, and adjust the speed sensor.
T90 filtration options
Series 90 pumps may have either suction or charge pressure filtration to filter the fluid entering the
circuit.
The suction filter is in the circuit between the reservoir and the inlet to the charge pump, as shown
below. The use of a filter contamination monitor is recommended.
Suction filtration
Charge pump
Filter
Hydraulic fluid reservoir
Adjustable
charge pressure relief valve
To pump case
To low
loop and
control
Manometer
P102 003E
T90 suction filtration operation
The suction filter is in the circuit between the reservoir and the inlet to the charge pump, as shown
above. The use of a filter contamination monitor is recommended.
T90 charge pressure filtration operation
Filtration options R, T, P, and L are pressure filters mounted on the pump or remotely for ease of servicing.
You will typically find a 100-125 µm mesh screen, in the reservoir or the charge inlet. This system requires
a filter capable of withstanding charge pressure (reference to atmosphere - add case pressure).
Charge pressure filtration
To pump case
Charge pump
Hydraulic fluid reservoir
Filter
To low
pressure
side and
control
Screen
Adjustable
charge pressure
relief valve
P102 004E
T90 MDC operation
The manual displacement control converts a mechanical input signal to a hydraulic signal using a spring
centered four-way servo valve. This valve ports hydraulic pressure to either side of a dual-acting servo
piston. The servo piston rotates the cradle swashplate through an angular rotation of ±17°, varying the
pump’s displacement from full in one direction to full in the opposite direction. The angular position of
the pump swashplate is proportional to the rotation of the control input shaft.
Service Manual
Series T90 Axial Piston Pumps
Operation
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©
Danfoss | March 2020
AX216086485386en-000101