Thyristor and switch controlled power on.

[RW74_Valiant]

I left out the ignition switch and other symbols for simplicity.

Is this correct, otherwise?

 

[Bluejets]

The SCR will latch on by pressing the start push button and then remain on indefinitely until the main power switch is operated
(Under high current condition I might add) which in effect, negates the use of the SCR in the first place.

Instead of offering possible circuits to do what you may or may not want, better to state the outcome you are after.
Along with the above, starter motors can draw upwards of 600 to 800Amps at start up which is (one reason...more practical ) why they used a start solenoid.
The latter is in many instances, more than enough of a solution.
............... but who knows what you are trying to do.

 

[Delta Prime]

The resistor represents your load or your starter see Here.

 

[RW74_Valiant]

The stock configuration is key on, push button start.

I'm trying to add a switch and a means of selectively subletting power from that switch to the starter through the main power feed to the solenoid.

By holding the start button and pressing the thyristor gate button, it adds another layer of anti-theft to the mix.

I've already added a thyristor between the alternator and the battery. That works with key on power and a push button. There is also a toggle switch to turn the alternator's field exciting lead on and off. The thyristor to battery is like selecting "yes" to verify.

There is an "On-On" toggle switch that overrides high and low beam selection and powers both in the down position.

In the power lead from the override solenoid, there is a thyristor in place so that you have to "verify" your selection by pressing the "yes" button.

For anti-start, do I instead, put the thyristor from the starter to ground, as that is how I've seen boiler pump wiring diagrams done.

Is there a difference in wiring between AC and DC?

These are what I'm using and the trigger voltage can be as low as 2v.

 

[Bluejets]

As I said, you are defeating the purpose of the entire circuit as the starter current can be anything for 600 to 800 Amps.

 

[RW74_Valiant]

As I said, you are defeating the purpose of the entire circuit as the starter current can be anything for 600 to 800 Amps.

Right and the thyristor is, likewise, rated for 0-1200 amps.

 

[Bluejets]

In a deep well......... Apart from the point which you already missed, apparently, the off current has to be handled by the commutating switch.
In your case the main power or off switch depending on which circuit you use.
Hense, the whole circuit is a waste of time.

 

[danadak]

Right and the thyristor is, likewise, rated for 0-1200 amps.

Thats not correct, the non repetitive single cycle rating is high,
for mS kinds of on time, not time it takes to start a car in seconds.



Go to digikey and screen for ratings. Attached is a "typical" part you could use


Regards, Dana.

 

[RW74_Valiant]

In a deep well......... Apart from the point which you already missed, apparently, the off current has to be handled by the commutating switch.
In your case the main power or off switch depending on which circuit you use.
Hense, the whole circuit is a waste of time.

Multi-step security is not a waste of time.

61 items on a pre-start checklist is a waste of time.

Stranded and calling the police because of car theft is a waste of time.