Jaguar VBus Fault

[davidthefat]

Anyone experienced that before? Anyone know of a potential cause of that problem? I presume a short. Is it recoverable, or is the Jaguar dead?

[andreboos]

What's your battery voltage when idle? When under load? Usually the fault is a result of a stalled motor drawing too much current, or a low battery voltage to begin with.

[davidthefat]

Originally Posted by andreboos

What's your battery voltage when idle? When under load? Usually the fault is a result of a stalled motor drawing too much current, or a low battery voltage to begin with.

It's just one Jaguar, other two are fine. The Jaguar has an over current protection that usually resets itself, but this was persistent for a full day.

[Matt Krass]

Originally Posted by davidthefat

It's just one Jaguar, other two are fine. The Jaguar has an over current protection that usually resets itself, but this was persistent for a full day.

We're going to need some more information:
What were you doing before and leading up to the fault?
What diagnostics have been done to identify the fault? (i.e. how do you know its a vbus fault and not something else?)
PWM or CAN?
What kind of motor and mechanical load is being driven?

Matt

[davidthefat]

Originally Posted by Matt Krass

We're going to need some more information:
What were you doing before and leading up to the fault?
What diagnostics have been done to identify the fault? (i.e. how do you know its a vbus fault and not something else?)
PWM or CAN?
What kind of motor and mechanical load is being driven?

Matt

I did not witness the actual malfunction. It was driving perfectly fine during lunch (I was driving). But the period after that (may be 20-30 minutes after), one of the jaguars gave out. So today, I switched the drive motors to a good black one, but then same story as yesterday, the other jaguar blew out (not the black one, but a grey one). The gearboxes were cimple boxes and CIMs were used.

The diagnostics was done using the TI's Jaguar flasher. So it was daisy chained using CAN cables to the computer and the flashing software indicated a vbus fault. The motors were not driven by CAN, but by PWM.

[Al Skierkiewicz]

David,
A Vbus fault could be caused by a bad crimp, bad breaker or improperly terminated wiring in the PD. It is simply an indication that when you draw current, the voltage drops feeding the Jag. You might get the same fault with a motor that is drawing a lot of current but not enough to throw a high current trip.
Check every inch of the wire between the PD and the Jag that is faulting looking for shorts, bad crimps, whiskers, loose hardware. Try spinning the motor by hand and see if there is a lot of resistance to your spin. It could be a bad motor, or improperly mounted motor on the transmission. If it is a drive motor, do you get the same results with the wheels off the floor?