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Choice of hydraulic fl uid
The Hägglunds hydraulic motors are primarily designed to operate on conventional pet ro le um based hy drau lic
oils. The hydraulic oil can be chosen in consultation with the oil supplier or your local sales offi ce, bearing
the following requirements in mind:
General
The oil shall have FZG (90) fail stage minimum 11 described in IP 334 (DIN 51354). The oil must also contain
inhibitors to prevent ox i da tion, corrosion and foaming. The viscosity of mineral oil is highly dependent of the
tem pe ra tu re. The fi nal choice of oil must depend on the operating temperature that can be expected or that
has been established in the system and not in the hydraulic tank. High temperatures in the system greatly
reduce the service life of oil and rubber seals, as well as resulting in low viscosity, which in turn provides
poor lubrication. Content of water shall be less than 0,1%. In Industrial applications with high demands for
service life, the content of water shall be less than 0,05%.
Recommended viscosity
At operating temperature: 40-150 cSt/187-720 SSU.
* Many hydraulic fl uids with VI-improvers are subject to
temperary and per ma nent reductions of the viscosity.
** Low viscosity gives reduced basic rating life for the motors
and reduction of max allowed power.
Fire resistant fl uid
The following fl uids are tested for Hägglunds motors (ISO/DP 6071).
*Vegetable fl uids give good lubrication and small change of viscosity with different temperature. Vegetable fl uids must be
controlled every 3 months and temperature shall be less than +45°C (113°F) to give good service life for the fl uid.
**Environmental acceptable fl uid give the same servicelife for the drive, as mineral oil.
Environmentally acceptable fl uids
Viscosity limits
Viscosity index = 100 recommended
= 150* for operation
with large temperature
difference
Min. permitted in continuous duty
Min. permitted in intermittent duty
Max. permitted
40 cSt/187 SSU
20 cSt/98 SSU**
10000 cSt/48000 SSU
Temperature limits
Normal operating temperature should be less
than +50°C (122°F)
Nitrile seals (std motor)
Viton seals
-35°C to +70°C
-20°C to +100°C
Nitrile seals (std motor)
Vition seals
-31°F to +158°F
-4°F to +212°F
Fluid Approved Seals Internal paint
HFA: Oil (3-5%) in water emulsion No - -
HFB: Inverted emulsion 40-45% water in oil Yes Nitrile (std motor) Not painted*
HFC: Water-glycol Yes Nitrile (std motor)** Not painted*
HFD synthetic fl uids
HFD:R - Phosphate esters Yes Viton Not painted*
HFD:S - Chlorinated hydrocarbons Yes Viton Not painted*
HFD:T - Mixture of the above Yes Viton Not painted*
HFD:U - Other compositions Yes Viton Not painted*
* Must be specifi ed in the order.
**The motor must have synthetic oil for the axial bearing.
Fluid Approved Seals Internal paint
Vegetable */** Fluid
HTG
Yes Nitrile (std motor) -
Synthetic ** Esters HE Yes Nitrile (std motor) -
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