Hardware


Not only did I FINALLY get the cnc system debugged after blowing it all to hell last weekend (along with my truck), it looked like the main filter caps and the fets could simply just be upgraded in voltage. This would prevent that last disaster that blew everything up and the system would get a nice increase in feed speed. The parts upgrade works great!! Wow, it went from 75ipm to 125ipm. It’s been up to 160ipm. But it was a little too unstable. At that speed there was a little oscillation at high rpm. Can’t tell if it’s the hardware or the pc that is the limiting factor. Makes it tempting to upgrade this old 800mhz pc to an old 3ghz Pentium. The faster the pc the faster the parallel port speed.

While debugging the cnc system, the quill suddenly stopped going fully upwards. It was hitting something hard. I called Don and he said the sheetmetal quill cover had broken tabs and was floating around. So tonight I called him and he walked me through how to take the top of the Bridgeport head apart to get the quill cover out. It was just a little work. Don nailed the diagnosis. I’ll get over to his house in the next day or 2 and pick up a new one from him.

Later this year, I will have had the mill for 10 years. Don has a guy that might sell him a real Bridgeport CNC machine. He won’t jump on it unless I give him the ok. It’s not a bad price. I could sell my Bridgeport to get some of the expense back. Those original cnc’s have power oilers, chrome ways and very wide ways at that, along with ball screws on all 3 axis. The tables are not long and skinny. They are a lot deeper. They were made for flowing lots of coolant on them. Don says the drawbar is some kind of quick change set up not the standard BP stuff. I told him we’d have to make it a step pulley setup. But maybe not. As long as it fits in my garage it won’t matter. Besides if I have to sell it, having it original would be more appealing to a potential buyer.

After delivering several more Dolphin boards it was time to assemble my system. I turned the key and as soon as the ready light comes on there was a gun like pop! I had forgotten to connect the igbt driver cables. At least the main board was not affected. All 3 igbt’s are shorted. I am lucky that my last customer was willing to give me his 3 spare igbt’s.

The #2 and #3 main boards that have received the Classic Dropout mod shipped today. They work very well compared to when I first got them running. What a thrill to finally see such great success with a problem that plagued these vehicles for years.

The first main board with the Classic Dropout mod shipped today!! Two more have
been modified and are ready to ship as well.

Some wonderful people sent me a pair of Dolphins to repair. Someone before them
had been into both of them deeply and did some serious damage. Pins were not put
back into connectors properly. The fets on the charger board were not even
parallel to the base plate. Both main boards and chargers were toasted. Even the
GFI hardware was missing from both units. Parts were missing from one of the
dc-dc boards. So when these systems arrived they had one board out of 6 running.

The one charger was the very latest revision from USE as it had a new board and
revision I’d not seen before. Only one fet was shorted, the other was fine. My
standard rebuild is to replace both fets, both relays and the diode weather they
are bad or not. So that’s what it got. I was very happy to see that the T1
current transformer survived the onslaught of failure.

One main board had the standard shorted bridge rectifier that goes along with
the shorted charger fets. The fet driver pwm output was fine however. But it had
happily open circuited the traces that usually just get shorted to other things
and cause a whole other set of issues. So some jumpers were added to the new
bridge rectifier. The board made it through my long QC list of tests and runs
well in the truck. Both boards got the regen upgrade (I modify the Dolphin to
increase the regen output by 40%) and the Classic Dropout mods for vastly
improved reliability and a better driving experience.

Once the charger was supposedly rebuilt, and the main boards repaired, It was
time for a test run. The Dolphin booted fine. But as soon as the throttle was
pressed the Dolphin faulted with a sizable thunk and gave an IGBT fault. It
turned out that the large diode on the charger board, when shorted, ties the
motor’s neutral line to the pack negative. That’s essentially a short across the
output of the Dolphin. It was odd at the time that none of the Dolphins IGBT
fault circuitry was triggered. All of it was normal. Yet I got an IGBT fault. It
turns out that the software looks for a reasonable load at various throttle
positions. Since the load was nearly infinite at low throttle it protected
itself by disabling the IGBT’s by not energizing them rather than the IGBT
circuitry sending a fault.

Then there are the mice that got in these Dolphins. They love eating insulation
off of wiring. Especially teflon wire. Then of course they have to use the HV
section of the Dolphin board as the bathroom.

After all of the repair work, and the passing of the many bench tests, it was
time for a test drive. The first board had dropouts so badly, that it could not
even pull itself back into the garage. I would say a dropout every second. The
next board dropped out every 15-20 seconds. After much studying and testing over
4 years, this really bad board made it a little bit easier to diagnose what was
causing the classic dropouts. Thankfully I figured out the dropout issue as
these boards were destined for the scrap bin! I pulled a 3rd board out of
mothballs that had bad Classic Dropouts, and it too was cured of dropouts with
the mods I had made to the other two boards.

After performing the Classic Dropout mod, I took both Dolphin boards for another
ride in my truck. Zero dropouts at very high regen or very high acceleration.
Nice improvement! I went for a walk at the park to enjoy the rare sunshine. I
noticed a bad coolant leak as I walked back. The bottom plate on the Dolphin
chassis is just .125″ thick aluminum glued and screwed on. The glue is very
brittle. When I used my cooling system pressure tester on the radiator, the
Dolphin cooling plate squirted coolant all over. It’s almost impossible to get
the tiny red-loctited screws out. It takes quite a while to scrape all of the
adhesive off too. I’m about 60% done. Makes me think this is another ticking
time bomb. This is the second Dolphin I have had that has cooling plate leakage.

Time to get to it!

Better charger fets were ordered today. The wattage rating is double that of the original fets. The rds of the IXFH44N50P-ND is .140 ohms. Rds on a IXYS IXFH26N50Q-ND is 0.20 ohm vs 0.25 on the original IXFH21N50.

The original MR826 charger diodes are too hard to get. So I found an equivalent at Mouser. 625-GI828-E3, 5.0 Amp 800 Volt.

I found that all of my spare charger boards have a bad T1 transformer on them. The secondary is open circuited. Rick had rewound his 5 years ago. So I am ordering wire and going to rebuild all of mine as well. They hold 407 feet of either 40awg or 41awg. Rick rebuilt his with 40awg. My math shows that it should be 41awg.

Seriously. It’s freakin’ solved after 4 years of research….

One of the boards that arrived for repair last week, was by far the worst I’ve
ever seen for dropouts, and it flashed the fault indicator in a very radical
fashion. It is now perfectly drivable!! No dropouts under acceleration or regen!
I was in total disbelief!! It works? Must be a mistake!! So I grabbed the second
board in for repair. Dropped out every 15-20 seconds. Made the same
modifications to it. Now it’s smooth as glass too! Zero dropouts under
acceleration or regen!! I had a third board laying around for years who’s only
crime was having massive repetitive dropouts. The modifications completely
stopped all traces of dropouts on it too. All 3 of these boards drive perfectly
now! Am I dreaming!!?? Feels like the Twilight Zone around here!!

Three boards saved from the junk pile. I have seen many more just like them.
That feels so good!! Many owners have this problem right now.

The Dolphin hardware has component values that are just barely within spec. With
miles of driving, time, and thermal cycles, the hardware goes out of spec, and
the Dolphin starts faulting, usually without any faults shown in Dolcom/Dol7.
I’ve posted this in the past. But the faults are felt as a sudden shudder in the
drive train. An instant loss and then instant return of power lasting only a
split second. It can rattle your fillings loose!! Some do it rapid fire, one
dropout after another. It’s all the same problem with the hardware going out of
spec. I found the faulty hardware!! Finally!!

During this research, I found an old quality control document from USE. It was a
long list of things that needed to be checked on their test fixture after each
board was assembled. The items on that list were very telling. So I have figured
out the procedure for checking most of the items on that list on my test
fixture. This ensures that the board gets thoroughly checked. I use it on every
board, just like the factory did.

Since it’s still very cold over most of the country, now is the best time to
have the offending boards with dropout issues repaired. The cold always makes
the dropouts worse. It’s the best season to ensure that the boards work in the
worst conditions of the year. Dropouts are less common in the warm months.

Send me your board and I’ll make the classic dropout modification and put your
board through the checkout list on my test fixture for $50 + shipping. Pack your
board very carefully, like it was your first born baby.

Mike

The board layout for the 160ah Thundersky/Sky Energy lithium cell BMS is finished. I’d like to scale it down to also fit the 90-100ah cells, but that takes another board layout session since the 160ah cells are so large compared to the 90-100ah cells. For now getting the thermal paths, thermal cycling, and basic operation tested is a higher priority. Making a board that will fit both the 90-100ah and 160ah cells would be the next task. At this point it’s setup to bypass 3 amps. 5+ amps is possible.

The BMS will control the charger output as well as the motor control if any of the set points are hit. I’ll get the BMS to Dolphin interface board going as well.

Here is an idea Mike Swift gave me for housing 10 parallel A123 cells in a similar shape to how the nicads are made. It’s tough to see all of the detail on the back of this receipt.

This P1 Dolphin board has the Mach220 chip that’s seriously damaged and the main relay fet vaporized from the board. Both instances left some low impedance paths between some traces. The Mach220 removal solved many of them. But the fet traces are damaged inner layers of traces. So the fet will have to be isolated and jumpered back into the circuitry.

All of the power supplies work with the Mach220 removed. So now the debug process starts. With a massive pile of projects on my plate, I don’t know how much more work this board will get until I have more of the projects completed.

This is how the board arrived. The 5v rail powered this Mach220 to death. Amazingly the 5v reg still works.

Here is what a correctly removed Mach220 location looks like. Zero lifted pads or traces. A socket will get installed here.

This fet had to have been jumpered to try and operate the main contactors directly. This is what happens.

« Previous PageNext Page »