Stalling on startup

[chuckm]

Four times in the past month my 2013 Focus has started as usual, I back out of the drive, shift to drive, it moves forward about two feet, jerks, gives an aural and dash warning to stop safely, the green light disappears, and it is dead. I may have to try to restart it several times before I can restart it and drive as usual. The last time, it stalled immediately again after restarting. Any suggestions?

 

[amped]

Total WAG. Possibly the reversing contactor is sticking and not making good solid contacts for the default current path (for Drive) after being switched to Reverse. I'm not certain, but I imagine that the FFE's controlling electronics monitors the high voltage contactors for temps and arcing and/or contact separation.

 

[edriver]

See the SSN thread http://www.myfocuselectric.com/forum/viewtopic.php?f=15&t=900&start=640

 

[triangles]

Total WAG. Possibly the reversing contactor is sticking and not making good solid contacts for the default current path (for Drive) after being switched to Reverse. I'm not certain, but I imagine that the FFE's controlling electronics monitors the high voltage contactors for temps and arcing and/or contact separation.

I could be wrong but I believe there is no reversing contactor. I would think the controller would simply revers the field for reverse. But yeah it sounds like an auxiliary safety contact on one of the contactors or possibly a corroded connection would be the culprit.

 

[WattsUp]

Total WAG. Possibly the reversing contactor is sticking and not making good solid contacts for the default current path (for Drive) after being switched to Reverse.

I could be wrong but I believe there is no reversing contactor.

There is no "reversing contactor". The field polarity in the AC motor is simply (and purely electronically) inverted, driving the axle in the opposite direction.

In fact, nothing mechanical occurs when "shifting into" reverse in the FFE, other than the movement of the gear stick itself, which is effectively nothing more than a glorified electric switch, providing an input to the computer, which controls the inverter, which generates magnetic fields within the motor, which (finally) turns the wheels.

When backing out of a parking spot, I often shift from R directly into D without completely stopping (or using the brake pedal at all) in order to drive away. Once in D, the field polarity is silently inverted from the R direction and, when I apply the accelerator, this counteracts the reverse motion of the car and begins to generate forward motion. Btw, this is not "bad" for the car in any way, as all that is happening is magnetic fields struggling to overcome each other within the motor. Unlike in a transmission full of gears, there is nothing mechanical that could "break".

All EVs work this way. Same exact thing happens in my Model S.

 

[amped]

Sorry, I guess I had DC motors on the brain

 

[triangles]

When backing out of a parking spot, I often shift from R directly into D without completely stopping (or using the brake pedal at all) in order to drive away. Once in D, the field polarity is silently inverted from the R direction and, when I apply the accelerator, this counteracts the reverse motion of the car and begins to generate forward motion. Btw, this is not "bad" for the car in any way, as all that is happening is magnetic fields struggling to overcome each other within the motor. Unlike in a transmission full of gears, there is nothing mechanical that could "break".

All EVs work this way. Same exact thing happens in my Model S.

So what happens when you put it in R going down the freeway? :lol: