Saturday, October 24, 2009

Saker GS750V motor and wheel rotation!

Today Ed, Mark and myself (with visits from Tom, Tabitha and Frank) achieved what we have been waiting nearly 12 months for. We had the GS750V powered up and turning it's own wheels!

Well done guys!!! This is an awesome achievement. Thanks to all that have helped us in getting to this point, both locally and internationally.

Read on for more details...

Our plan had the day broken into 4 phases:
1) Re-test the 30V test rig setup after it had been relocated from the software dev environment.
2) Test the 1.1kW motor from the test rig with the 150V test pack.
3) Lunch and forgotten encoder cable provided by Kirstin :)
4) Upgrade the 1.1kW motor to the Siemens motor in the GS750V and watch the wheels turn!

The setup we had is still very much a work in progress since the STM32 and Tumanako control board is not yet installed in the inverter casing. Hence the inverter and the control board where setup on a table beside the car for this test. The contactors where situated in a temporary but secure location which was convenient to get the power from the battery to the inverter.

You can see the setup we had for phase 2 in the photo below:
After a successful morning and a smiling visit from Kirstin, we moved into the business end of the day. We jacked the car onto blocks and connected up the Siemens 1PV5135 WS28 motor, which is already mounted in the car and connected to the gearbox. After an initial juddery rotation and a blown fuse (test pack fuse is only 30A so we don't stress the batteries), Ed discovered the encoder was hooked up incorrectly. So, rather than simply replacing the fuse, Mark upgraded it to a breaker which is resetable if something goes wrong and also easily used to make the pack safe during maintenance. Thank you Mark!

After addressing the encoder wiring and increasing the flux limits on our torque control, we got some very smooth motor control indeed. Check it out (please excuse the battle Ed is having with the forward/reverse torque control POT we had setup for the test in this video):

So, it's the home straight now! We need to complete the single Tumanako control board, finish off the wiring loom and complete the associated vehicle control software (adding additional safety checks and vehicle loom IO). Then we will be ready for dyno tuning (motor parameters need work) and of course squeezing in the first test drive :)

Also, expect to see a high quality video of todays test uploaded in the next couple of days. I'm currently looking for a cable from my sons video camera that I borrowed!? I hope I don't get into trouble :)


Thursday, October 22, 2009

Contactor control and mods

It has been a little while since our last post, but lots has been done. When we commissioned the clutch at the garage we grabbed the contactor box to investigate interfacing it with the Tumanako inverter. The box had a few "nasties" in it - the precharge resistor was switched in across both contactors with IGBTs - no galvanic isolation, at any point!

Last week Phil and I put together a bit of a plan to modify it for increased safety and to interface it with the Tumanako inverter's STM32 chip. We removed the IGBTs and instead installed a third contactor (a Gigavac GX12 Phil had bought previously as a secoundary safety device, now becoming a primary safety device). With the HV circuit now sorted out all we needed to do was interface these 12V coils with the 3.3V micro. A circuit was drawn up, and a quick trip down to the local electronics store and we were ready. I put together the circuit on a strip of veroboard, and with a bit of Phil's coding we had a basic IO test clicking the contactors in and out.

This week I have tidied up the contactor box, mounting the veroboard circuit while Phil attacked the precharge code. We are nearly ready to try out a decent battery pack, and if that goes well we will have the chance to try out the Siemens motor.

This will be quite a milestone: race motor, race inverter and contactors. The car will be ready to spin it's wheels (under it's own power) for the first time.

Stay tuned!


Sunday, October 11, 2009

Clutch commissioned

One of the things we need and want is a working clutch! From a safety perspective it is a physical safety valve, a simple way to stop the motor driving the wheels, is to push the clutch in. Still no gear stick controlled changes though (the linkage is missing), a job for Bruce at a later date...

After fitting the newly machined clutch line adapter (thanks Ed) and a length of flexible high pressure hose, we proceeded to bled the clutch.

Once this was done, we thought the clutch slave cylinder did not have enough travel to disengage the Tilton clutch plates. What was actually happening though, was that it was travelling too far and re-engaging at the end of the travel (after being disengaged at the half way point). Strange behaviour indeed and we are not entirely sure why it is doing this. It could be fixed with a stopper under the clutch pedal, but we would like to understand this better.

I'll be asking a few questions tomorrow. if you have any ideas, please let us know.

Anyway, it was good progress and big thanks to Frank and Ed for making this happen :)

Friday, October 2, 2009

Turning wheels...

You may be asking, what's happening with the GS750V (the Electric Saker)? As you may know, almost 12 months ago exactly we discovered that the inverter we purchased was a little deficient (due to software issues that have not been addressed by the manufacturer).

Thankfully, this is one of the areas the Open Source Tumanako projects have been making great progress in. If you have not been following the Tumanako projects, I suggest you take a quick peek at the Tumanako blog.

Although there is still significant work to be done before a full Open Source inverter and vehicle control software system is released, I can confirm we will see the wheels turning on the GS750V in the near future.

Stay tuned for the video!