Can someone please explain to me exactly how the ' suicide circuit ' works on a ward leonard control system? I have been told it is to cancelout residual magnetism in a field, although I am not sure which one...

-- Justin Ward (transition_au@planetaccess.com), November 24, 2000

Answers

The suicide circuit cancels the residual magnetism in the pole pieces of the MG set by "shorting" the induced current back upon itself.

This is done by contacts which will connect the current back upon itself, always with the opposite polarity, each time the car stops. This "kills" the residual magnetism, hence the name.

-- John Brannon (akaelevman@AOL.com), November 26, 2000.

i work at ward leonard.......please detail your question a little better and i will get back to you......i dont do the wiring, i work in a dif. dept..........but i will ask your ?

-- kevin p. (dljrfn27@aol.com), March 12, 2004.

suicide hooks the armature and series fields to the shunt fields. prevents residual magnatism from exciting the armature/series which would then excite the shunt more and then excite the arm more and so on... eventually the car could pulled through the brake and self destruct the generator, fry the motor, etc.

N

-- n (nswan@genelev.com), March 18, 2004.

In most Otis elevator control circuits, the suicide delay relay (SUD) is energized or de-energized by the closing of the contacts from the field and brake switch (H) This action causes the parallel NC SUD contacts in the GSEF circuit to connect the loop circuit with the GSEF field thus preventing further magnetic flux from building.

-- Sidney Thacker (sidthacker@aol.com), April 14, 2004.