speaking of tortoises -- why does one adjust the fulcrum?

The further towards to top (the turnout throwbar) you set the fulcrum, the smaller the movement; the more towards the motor, the more movement. You adjust it to where it hold the points against the stock rails but without deforming the turnout itself.

Ed.

in article snipped-for-privacy@posting.google.com, larry l. at snipped-for-privacy@tranquility.net wrote on 10/3/03 6:47 AM:

Changing the fulcrum does two things:

2) Changes the force of the throw.

They're inversely porportional - the further "up" you move the fulcrum, the less distance the point end moves, but the more force it has. Move the fulcrum "down", and the point end doesn't move as far, but exerts more force. The wire _does_ mediate this to some extent as it flexes.

However, the amount of force (in most all applications) is sufficient for the job, so basically you can move the fulcrum to fine-tune how far the points move... particularly in smaller scales, where you don't want to exert excessive force on the points. Set the movement to be just enough to close the points firmly, and all should be well.

The fulcrum really comes in to play in the larger gauges where you have to substitute a heavier wire to operate the switch blades. This wire is not as flexible as the wire supplied with the Tortoise and the fulcrum allows you to fine tune the range of movement so that the motor doesn't strain too much at the extremities of its throw.

Jim.

The fulcrum adjustment varies the length of the stroke. You want it adjusted so that the points are thrown all the way before the motor stalls.