Mechanical Engineering - Theory of machines - Discussion

In a steam engine, one method of obtaining the earlier cut-off with a simple slide valve is by increasing the angle of advance of the eccentric while the throw of the eccentric, steam lap and exhaust lap are kept constant. This method will reduce length of effective stroke of piston.

In a steam engine, one method of obtaining the earlier cut-off with a simple slide valve may be obtained by increasing the angle of advance eccentric but reducing the throw of the eccentric and keeping the steam lap and exhaust lap constant. This method will cause withdrawing or throttling of steam.