Hydraulics - Seafish
Hydraulics - Seafish
Hydraulics - Seafish
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66<br />
(?) SAQ26<br />
Using Table 3 determine the viscosity range of an oil<br />
designated SAE 20W/30<br />
Viscosity Index<br />
The viscosity of all hydraulic oils reduces as the temperature<br />
rises, and increases as the temperature falls.<br />
Some oils show a large change in viscosity when the<br />
temperature changes, whilst the viscosity of other oils changes<br />
very little.<br />
Viscosity 11<br />
0°F 210°F Temperature<br />
Figure 56.<br />
In Figure 56 you can seethatthe viscosity of oil B increases only<br />
by a small amount at low temperatures and this means that this<br />
oil would be suitable for hydraulic systems which have to<br />
operate in cold weather conditions. If oil A was to be used the<br />
hydraulic system would have a sluggish action at low<br />
temperatures due to the increase in viscosity.<br />
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