# Safety Interlock



## major (Apr 4, 2008)

nulluser said:


> I have finished the design of my safety interlock.
> 
> Just wanted to see if I did anything weird before I power it up at pack voltage. The bench test worked well.
> 
> The ignition signal fires a relay which provides aux battery power to the rest of the circuit. This is so the car's ignition line does not see so much current. This also turns on the ignition contactor (interrupts pack negative). SpeedOK is the signal from the JEGS speed switch and is high if the motor speed is safe. This needs to be high to fire speed relay. Finally, the switch in the pot box provides a ground for main contactor, and a relay that sends the on signal to the controller.


Hi null,

Don't use a resistor across the contacts on your negative contactor. Just a single precharge resistor is needed.

Also, I really do not like permissive switches or interlocks dropping out contactors. I reserve that for maybe an E-stop last resort. Otherwise use a run signal command interrupt to the controller.

Regards,

major


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## nulluser (Mar 4, 2012)

Good catch on the speed interlock dropping out the main contactor, I will make the change so it only turns off the run command to the controller.

Looking hard at how it's wired, I still think the second precharge resistor is needed because the controller has no other ground.

Thanks for taking a look.


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## major (Apr 4, 2008)

nulluser said:


> Looking hard at how it's wired, I still think the second precharge resistor is needed because the controller has no other ground.


I do a sequenced start. Close the negative contactor and then the positive (precharge) contactor after the controller voltage has come up to 90% or higher. This isolates the controller when both contactors are off.


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## nulluser (Mar 4, 2012)

I have added fuses to the drawing and made the correction to the Pwr signal going to the controller.

Here is the logic that the drawing implements:


IGN | SPEED | THRL | IC | MC | Pwr |
---------------------------------------
0 | 0 | 0 | Off | Off | Off | Ign Off
0 | 0 | 1 | Off | Off | Off | Ign Off
0 | 1 | 0 | Off | Off | Off | Ign Off
0 | 1 | 1 | Off | Off | Off | Ign Off
1 | 0 | 0 | On | On | Off | OverSpeed, Pedal Down
1 | 0 | 1 | On | Off | Off | OverSpeed, Pedal Up
1 | 1 | 0 | On | On | On | Normal, Pedal Down
1 | 1 | 1 | On | Off | Off | Normal, Pedal UP


0 = Ground or floating for positive logic
1 = 12v or floating for negative logic

IC = Ignition Contactor
MC = Main Contactor
Pwr = Controller ON Command


I don't think I'm going to use staggered or timed starts for this project. I will simply disconnect the Anderson connection for servicing.


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## ddmcse (Oct 9, 2008)

LoL , wow i was just checking this out I just realized what this Bike used to be, a waterbuffalo. It was bad ass for 1971. I had one of these when I was on my Suzuki kick. I had little collection of 5 different ones. my favorite was the T500 I took it to Daytona for bike week one year (1995)and got sick of people telling me how they learned to ride on one every time I stopped. 

we called her the water dog 
http://ddmcse.com/ecar/waterdog.jpg
3 cylinders,2 stroke, water cooled 

and we would rejoice to sound of the T500
http://ddmcse.com/ecar/rejoice.jpg
ning, ning , ning ning ..

you can't go to bike week without a photo "Op" like this

http://ddmcse.com/ecar/bikeweek.jpg
ha if you think that is good after I took this I realized what was going to happen next. she was going to get off the bike . that one gets sensored


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## nulluser (Mar 4, 2012)

ddmcse said:


> LoL , wow i was just checking this out I just realized what this Bike used to be, a waterbuffalo. It was bad ass for 1971. I had one of these when I was on my Suzuki kick. I had little collection of 5 different ones. my favorite was the T500 I took it to Daytona for bike week one year (1995)and got sick of people telling me how they learned to ride on one every time I stopped.
> 
> we called her the water dog
> http://ddmcse.com/ecar/waterdog.jpg
> ...


I felt kind of back hacking up a classic bike. http://www.junklet.net/html/make_page.php?n=ebike It was, however, a 150 dollar classic bike


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