Subject: RE: solid state relays
Author: murp-@aol.com
Date: Feb 5, 2002, 8:00 PM
Post ID: 1709573900
John,
Looks like you are designing an Electronic ignition here, except that
you are keeping the points. I think part of the advantage of electronic
ignition is that they usually use a different trigger mechanism than
mechanical points.
I have no experience with solid state relays, but I am assuming that
all the switching is performed by a couple of transistors, using a
fairly hefty power transistor as the output transistor connected to the
load. The circuit you describe could work, where the transistor is
turned on while the points are closed. When the points open, this
transistor would turn off, and I think that it probably would turn off
quickly enough. However, I think there might be a problem with the
voltage of the -ve side of the coil going to a value which might exceed
the maximum allowable collector-emitter voltage of the output
transistor.
I spent 10 years as an elecronic designer for telecom equipment,
mainly digital design, and have no experience with power electronics, so
the above is only my gut feeling. I hope you give it a try.
Brian
John Boettcher wrote:
| Ok, as long as I'm on a roll here. Has anyone tried a solid state relay to fire the ignition coil using the points to trigger the relay? I figure it would eliminate any arcing whatsoever in the points. Where I work we have ss relays that trigger with 0-32vdc and with only milliamps as a load. It can switch a 25amp load. So 12vdc to the + side of the trigger and the - side to the points. - side of ignition coil to one side of the ss switch and the other side of the switch grounded. My only concern is if a solid state relay will collapse the ign. coil fast enough for the spark. JB (Weld) |