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Contents 1 Energy loss 1.1 Power transfer through the silicone fluid? 1.2 Silicone oil doesn't become thicker or solid when heated !!!! 1.3 Viscous Clutch vs Torque Converter

[edit] Energy loss

This page should have some discussion or reference to the amount of energy lost in a viscous coupling unit. --Nil0lab 17:23, 2 April 2006 (UTC)

[edit] Power transfer through the silicone fluid?

According to Popular Mechanics and HowStuffWorks the silicone fluid becomes more viscous (thicker) when heated and that is what provides the power transfer accross the coupling, not friction directly between the plates. Which mechanism is correct? GrodenGlaive 14:26, 20 January 2007 (UTC)

[edit] Silicone oil doesn't become thicker or solid when heated !!!!

The mechanism described in the article 'Viscous coupling unit' is completely wrong!

The visco coupling works because of the hydrodynamic resistance or friction, which is proportional to the velocity [[1]]. At low speeds the hydrodynamic resistance is low (when you move your hand very slowly in water you feel no resistance) but the resistance increases at higher speed (you feel a resistance when you move your hand in water quickly). The same principle makes the visco coupling possible. At low relative speeds between the plates submerged in the thick fluid there is no significant torque transfer between the plates, but at higher speeds the hydrodynamic resistance and torque transfer increase.

As a model you could imagine a pot with honey and a shaft with a kind of propeller (=equivalent of the plates in the visco coupling) submerged in the honey. Think the pot is the one side of the visco coupling and the shaft with the propeller is the other side of the coupling.

Now when you move (rotate) the propeller very slowly (that means, when both sides of the visco coupling rotates with almost the same speed) you can move the propeller with low resistance in the honey (= there is no torque transfer through the visco coupling) but when you start to move the propeller faster (e.g. with a drilling machine) you will feel that a significant amount of the torque of the propeller will be transfered through the honey to the pot (the coupling effect appears).

Could somebody change the article accordingly (my english is too bad for that) because it seems that the fable about the miraculous change of the thickness of the silicon oil in the visco coupling seems to disperse quickly? I found the same wrong explanation of the visco coupling principle in the polish Wikipedia (apparently translated from the english "original").

Jar —Preceding unsigned comment added by 217.5.182.66 (talk) 15:33, August 29, 2007 (UTC)

[edit] Viscous Clutch vs Torque Converter

The original article is good.

The guy that says he has it wrong seems to be describing a torque converter. —Preceding unsigned comment added by 165.173.34.238 (talk) 14:12, 6 March 2008 (UTC)