Hooked up 400VDC cables backwards to motor

[efender]

Hey guys, I could really use your help.

I took out my motor recently to try to get it to run outside of the car. I extended all of the low voltage cables, I got an electric water pump to circulate water through the motor, I grounded it to the car chassis.

But, when I extended the 400 VDC cables, I hooked them up backwards!

Did this mess up any of the electronics on the inverter? Would there be any fuse or reset button I could try?

 

[Lloyd]

and you did this because?

 

[chillaban]

So I used to work on this stuff for a living….

You can expect most inverters to have many layers of software and hardware safety against incorrect bus polarity (and incorrect bus voltage in general). Most likely you did not damage anything on your inverter, but please do realize how dangerous what you did was!

In 3 years of working on this stuff, thank goodness I've not see anything go wrong with my HV inverters, but I have seen incidents where LV inverters blew their electrolytic caps due to mistakes like this, and it was not a pretty sight. Of course if that happened with HV, you would probably be talking to us from the hospital.

Double, triple, quadruple check this. And messing with jerry-rigged HV equipment in a garage is not at all appropriate. In the industry, we were required to be on the other side of a reinforced lab with 2-inch bulletproof plexiglass.

 

[efender]

So I used to work on this stuff for a living….

You can expect most inverters to have many layers of software and hardware safety against incorrect bus polarity (and incorrect bus voltage in general). Most likely you did not damage anything on your inverter, but please do realize how dangerous what you did was!

In 3 years of working on this stuff, thank goodness I've not see anything go wrong with my HV inverters, but I have seen incidents where LV inverters blew their electrolytic caps due to mistakes like this, and it was not a pretty sight. Of course if that happened with HV, you would probably be talking to us from the hospital.

Double, triple, quadruple check this. And messing with jerry-rigged HV equipment in a garage is not at all appropriate. In the industry, we were required to be on the other side of a reinforced lab with 2-inch bulletproof plexiglass.

That's good to know about the software / hardware layers of safety.

Good advice too about triple checking things and keeping safe incase something explodes.

 

[mongo]

So I used to work on this stuff for a living….

You can expect most inverters to have many layers of software and hardware safety against incorrect bus polarity (and incorrect bus voltage in general). Most likely you did not damage anything on your inverter, but please do realize how dangerous what you did was!

In 3 years of working on this stuff, thank goodness I've not see anything go wrong with my HV inverters, but I have seen incidents where LV inverters blew their electrolytic caps due to mistakes like this, and it was not a pretty sight. Of course if that happened with HV, you would probably be talking to us from the hospital.

Double, triple, quadruple check this. And messing with jerry-rigged HV equipment in a garage is not at all appropriate. In the industry, we were required to be on the other side of a reinforced lab with 2-inch bulletproof plexiglass.

For typical ones sure. For this implementation, I can see not adding the extra loss of a reverse protection circuit that can handle full load, especially since HV leads should never get swapped. If the contactors are cycled one at a time, the reverse connection could be detected before the body/ catch diodes in the switching semiconductors get to conduct the full pack output. Part of the isolation check?

 

[efender]

It was pretty easy to get them mixed. None of the high voltage cables are labelled for polarity. They are both the same color and look almost identical.

I still should have double checked it.

Do you guys think that there would be any sort of fuse that would have burnt out over this? I checked the fuses under the hood, but maybe something in the battery or inverter?

 

[chillaban]

For typical ones sure. For this implementation, I can see not adding the extra loss of a reverse protection circuit that can handle full load, especially since HV leads should never get swapped. If the contactors are cycled one at a time, the reverse connection could be detected before the body/ catch diodes in the switching semiconductors get to conduct the full pack output. Part of the isolation check?

Reverse protection voltage sensing is usually done by hardware (not firmware) as part of the power-on check before closing the contacts that connect the terminals to the big capacitor. Definitely the IGBT gates would have their own undervoltage / reverse voltage protection, but by that point you would've caused significant damage.

You typically need the ability to disconnect bus voltage as a safety mechanism anyway for hardware malfunctions at the inverter level, voltage sensing is cheap enough that I can't imagine them skipping it, even for a 100% in-house system.

 

[brkaus]

Interesting project. You going to put it in that little orange and yellow car in the background of the first photo

 

[thecloud]

and you did this because?

I'm imagining that Little Tikes car in the first photo is going to go very, very fast when he's done.

 

[efender]

Interesting project. You going to put it in that little orange and yellow car in the background of the first photo

Haha, no, that thing is already a zero-emissions vehicle.

I'm planning to put this motor in a Land Rover Defender.

But before I put it in, I want to see how much I can remove from the system and still have it driving. For example, I know it'll still drive without a door on, but it won't drive too fast without the wheel speed sensors hooked up.

Unfortunately, I didn't get too far. Haha

 

[brkaus]

You did see hsr motors? Motor and controller. Extracted from Tesla’s. Not as cost effective as a salvage, but already self contained.

Anyway, sounds fun and more learning experience your way.

 

[Kristoffer Helle]

Wk have some HW you can use

 

[mongo]

Reverse protection voltage sensing is usually done by hardware (not firmware) as part of the power-on check before closing the contacts that connect the terminals to the big capacitor. Definitely the IGBT gates would have their own undervoltage / reverse voltage protection, but by that point you would've caused significant damage.

You typically need the ability to disconnect bus voltage as a safety mechanism anyway for hardware malfunctions at the inverter level, voltage sensing is cheap enough that I can't imagine them skipping it, even for a 100% in-house system.

I think we are on the same page.
The disconnect system is the two contactors + pyro fuse in the pack. No reason to have redundant cut out in inverter itself (unless you want the extra fault tolerance to run on the other motor in AWD vehicles).
During HV activation, the HW/SW checks for isolation between each HV line and chassis. This check could also verify HV polarity and abort the activation sequence so that the reverse polarity is never applied to the inverter. The system could also have sense leads to the switched side of the contactor and the input to the inverter, that would eliminate the need to energize the contactors (one at a time) to check polarity.

 

[Kristoffer Helle]

HSR Motors

 

[builds.love]

I am building a custom Overlander using a Tesla Model 3 Battery for the living space. On the HV battery to motor cable there is a 1 and 2. Which is positive? This will be connected to a 10KW Sandi Inverter.

 

[builds.love]

Needing to amend my previous post, I found more clear information to confirm. The Tesla Model 3 battery to motor cable I have has a 1 & 2. Based on the photo / forum, I can see the plug would be inserted. Making #1 Negative & #2 Positive.

 

[pilotSteve]

I am building a custom Overlander using a Tesla Model 3 Battery for the living space. On the HV battery to motor cable there is a 1 and 2. Which is positive? This will be connected to a 10KW Sandi Inverter.


View attachment 996800

DC volt meter will tell you.

 

[builds.love]

DC volt meter will tell you.

When there is no current? Come on, don't comment with crappy answers. I clearly would try this, if I could. The battery will not engage contactors without a load and my load is a very expensive high current inverter.

 

[pilotSteve]

That doesn’t make sense to me. if the terminals you want to use are powered, there will be voltage present even with no load.