Belktronix Blog
I created this page with a dual purpose, one of which was to remind me what my day to day duties consist of as a
hardware manufacturer. The other was to give a glimpse to the viewer what's going on here as well. I hope to update it
at least weekly.
3/3 Well, got some good news and bad news. Bad news is the Dyno generator is maxed
out. Even with max PWM on the generator, it still slips. I figure its probably seeing
around 50HP, 5x over its rating. I was planning to use a GE 11" shunt wound that I
have. But when I took off the end plate, the rotor was a puny 5" in diameter. Even with
its rating of 25HP, I really have to wonder if it can do 5x more (which would be good).
The good news in all this effort, I didn't break anything in the process, but I did see the
belt twist and start to walk on the idler. I could get another generator motor and
somehow tie the shafts together with a common coupler, but that seems like it would be
more of a problem than a solution. The end shaft on the generator is 1/4" OD,
eliminating the possibility of a shaft to tail drive configuration. Ok, who thinks this GE
motor will do >100HP intermittent?
Where's the rest of the blog? Right here
Thoughts? Ideas? email me here
3/6 Still reviewing my options regarding the dyno, that will be back-burnered for a bit while I get sub assemblies built for
EV kits in the queue. Right now PCB's are being built and loaded. Also have to catch up on some things around here
that have been idle for way too long (while the weather permits).  Back to work!
3/9 The only dyno generator options on the table at the moment are a STC 50kW generator head on ebay for $1200.
3 phase would be better, but has a 8 week lead time. I don't know how they would do at 3600 rpm and above either,
they look to be more low speed service than above 1800rpm. After talking with WEMOCO, they may have a Sepex field
coil to use with a ADC8 motor as a generator. The limiting factor there is they seem to think its limited to 75 ft/lbs.
Loading LionMons for 2 EV kits, along with drilling PCB's for the remaining builds...
3/14 Dismantled the Dyno again, and pulled apart the generator tail section to see if there
was a means to couple 2 motors together. The larger portion of shaft is closest to the rotor,
requiring pulling it from the stator. Being a PM rotor, I don't think thats going to happen.
Once I would clear the stator, it would likely pull itself to the nearest metal object and cling.
Then a intermediate section would be needed and a coupler to join them together. Its the
cheapest option on the board at the moment. Other than that, building up boards for the
builds in queue. LionMons take the longest to build/kit, since there's 45 of them!
3/23 Had to be away from 3/16 to help my mom recover from surgery from breaking her arm! Once she was back at
home I had to return to take care of things here and managed to take some boards back with me to work on. Now that
I'm back I need to get caught up!
3/30 This week was a little better, I managed to start reworking the dyno to use an AC induction motor as a generator.
Its only a 20HP unit, but should be able to handle 100HP peak. I had to drill into the motor faceplate to match the
existing holes from the Brushless motor. Continued on some potbox board builds and getting ready to stuff another set
of LionMons. Now I have to get my friend Rex to tweak some code to generate power (voltage mode) with the AC motor.
His job cut their hours, which got him some consulting work and is eating into his spare time for projects like this one!
Yikes! It would be nice to be funded to have him work full time on this stuff, I'm sure he would like it.  
4/3 Pushing forward on the dyno rebuild, have a taperlock bushing on order, should be here this Mon. Got my 3 phase
make a circuit to set the RPM limit of the generator section, so that once I get there, I begin to generate power back to
heat scoring on it, likely from a big side load. Hopefully I can get by the initial checkout without having to replace it. The
build is moving along albeit slower, but moving. Have Potbox and Vehicle Integrator cases to build up this weekend.
4/9 Got the bushing installed and the dyno is up and running with the 3 phase AC motor functioning as a generator.
The part now is to safeguard the electronics for any -just in case- scenarios. OVP shutdown is now installed, turning off
overshoot if the breaker for the AC generator opens under a full power load. The front bearing on the AC motor is also  
letting me know its time is limited. The other obstacles (hopefully on the small side) is dealing with the AC rectified
ripple current coming back into the DC motor controller, along with any generator control loop delays adding to the
ripple magnitude. It could be problematic for my electronic circuit breaker forcing a higher limit setting than needed.
The hardware build is moving along slowly in the background while these things are ironed out. Back to work!  
4/15/09 Moving the current hardware build schedule back to the top of the list. Circuit board assemblies are finishing
up this week along with the mechanical potbox assemblies. Also will be working on the flooded PCB interface for the
charging system. More to do, so back to work!
4/20 The larger mechanical assemblies for the kits in queue are being built this week. Being in the high 90's puts a limit
the controller can do regen, I managed to squeeze in some weekend time on the Odyssey and added Otmar's regen
circuit. I didn't realize it would be that abrupt, but it works! After the builds are completed I will build one for the Scirocco
and test it out. It will be interesting to see how it works with much more weight added into the equation. Back to work!
4/27 Still pushing the build forward, the weather has cooled down to make it enjoyable to work in the shop again.
Trading hot days for cool nights only invite mosquito's to help with my west nile dosage. I finally got the right tap for the
large power terminal nuts I have to make. I don't think the stamped steel ones would go over well in the looks
department. I've got my hands on some coldplate material that I'll be testing out soon as well. It will scrub some cost
from the system, so that will help for the higher amp configurations. My friend Rex sent me some code yesterday to try
out on the dyno AC motor, so that's on the plate to do very soon as well. Found I ate the threads on the heim joint for
the rear suspension, possibly from the jerk the regen puts on the chassis, so that will have to be fixed to be safe. At
this point I think the light weight is more troublesome with regen. It hits pretty hard and can slide you forward in the seat!
5/2 Building up the first dual charger for the 800A system, I expect it to be uneventful with the exception of making
templates for the heatsink and cover and documenting the project. I developed system-build pages for customer web
access so they can check on how things are progressing, and attempting to update that on a daily basis. I managed to
fix the Odyssey heim joint a few days ago to help with 20 minutes of rapid stress relief. Needing a code update for the
dyno to have a pot set the RPM limit, but with Rex working on another project at a megabusy level, I'm down at the end
of the list. I still have to incorporate over-speed limits and a safety shutdown sequence if I have a voltage spike from
the generator. Got more boards to fab soon as well. A battery died on my lab pack so off that went for a replacement.    
5/11 WOW, how time flies! I thought I had updated this blog more recently than the 2nd. Beginning to wire up the dual
the DC-DC on. Got a replacement battery for the lab pack today to install, and a code update for the lab dyno uC. I
now have a pot to set the dyno speed limit where it will start to generate. This way I can see the effects of the controller
as its pulling a high current load (like going up a hill). I hope to see the point where the WarP 9 peaks as well (full
PWM). Hopefully tomorrow I'll get to push it harder to see what it can do. Added another 800A customer so that system
is added to the build schedule along with ordering parts. All other builds in the queue are moving along with no issues.
Revising the system build pages as well to make it more sensible. I know there is more, but I'm tired, time to hit the hay.
5/14 Still pushing system builds forward, now they're sharing time with work on the Dyno and parts ordering. I'm still on
a power supply diet for the dyno primarily to keep things from getting out of hand. There was some noise on the
generator tach signal that would on occasion pull the speed to 0 in < 1 second. Fixed that, but since I'm below the
normal operating voltage for the AC induction motor, I need more slip to operate in a field weakened state at a lower
voltage. Once I feel things are stable and I have the OVP and load dump circuits in place, I'll go ahead and run it off the
pack to see how its doing. Thus far, its progress, no smoke or burned up parts. Its too costly to be making careless
mistakes that can be avoided with a little more time and careful planning. Unfortunately, no government stimulus funds!
5/25/09 Very busy since last post, with too many things going on at once! The system builds are progressing forward, I
revised a PCB in the new dual charger to keep the internal fan on when either the charger or DC-DC is on, with the
power wiring expected to be done today. Hopefully tonight I can plug it in and charge a pack 2x faster. I still have to
finish the protection circuitry (put it all on one board) for the dyno. Its a little different than the BLDC gen setup, if the
buck stage failed, the WarP 9 would slow down. With the power stage failure on the AC gen, it will speed up. I have
tach's on both motors in case the belt fails. I have to be ready for any failure mode to keep things from going volcanic
amps. Now that my daughter's out of school, no more back and forth trips (save ~2hrs/day) to put back into the
business. With my wife feeling better that will definitely help things out too. I'm noticing that purchasing parts, some
prices are creeping up, I can't figure that out in a down economy. Must be tied to what gas is doing. I managed to
sneak in a LiFePO4 into the Scirocco pack to see how China High Power cells do. So far, so good. Only got 1 to test,
so not really a datapoint there. Yep, I can do some interesting stuff with the hardware, not that I'm recommending this
combo, but for testing purposes (see the batmon web page)...My friend Rex has a little time on his hands available, so
hopefully I won't overload him with a bunch of 'lets try this out...'. Still plenty to do, I better get back to work.
5/30 Trying to keep the blog updated before time gets too far ahead of me. I revised a tach/shutdown board only to
find I had a few more revisions to do on it (no jumpers). Fab'd those today along with some LionMons as a reserve
stock of bare boards. Once I get the Tach circuit wired in on the dyno and add a load dump to the generator (in case
that circuit breaker decides to open up) I'll run the entire dyno on the battery pack and see how far I can get power
wise. 800A is allot of torque on a 9" WarP motor, so hopefully I can surpass my previous 650A mark without breaking
anything in the process. I still have to layout the dual charger cover, I have allot of ideas, but it has to make sense
once its installed to be easy to wire up. I don't think having I/O ports on every side is a good idea, so thanks to a little
cardboard will help that process. As usual, when things start to head towards a max power dyno event, I get a little
nervous. Maybe its due to the engineer I worked with back at FMC. He had no problem blowing things up, a few times
we had $10k days. That's how much money went up in smoke, unfortunately I don't have that much green to convert
silicon into vaporware, so I HAVE to be cautious. I would rather have things turn off before I get to that point!   
6/4 I've got all the protection functions wired in, tried a few runs on a 500a system for a customer (starting small), but
dyno hardware and found something I thought would be a problem. Corrected that, then it didn't work at all, so I
started to look over all the parameters that the code runs through during startup and tracked down a potential power
supply race condition. Tried it again and found the negative slip isn't working as expected, so more code to crack and
figure out why that is. I've been on this for 4 days already I think once this is fixed, things should be up and running
and I can start shipping hardware out. Sorry for the delay, if you're on the waiting to receive list, this is a step I don't
want to leave out before I ship controllers. Otherwise its just testing current on a field, and I don't think that's
conclusive enough to put in someone's car. Its been a tiresome venture, but I have to be persistent. I have a punt
game just in case, but that involves a larger BLDC motor, a mounting plate, and a dyno motor swap (full dyno
disassembly since its the bottom motor) so I'd rather not go there unless I absolutely have to. Gotta go, more to do...
6/5 OK much progress today, found the internal clock on the AC micro was off, causing the code to be executed faster
than expected. Also lowered the gain for the speed limit on the generator, now its more stable under load. A few other
code instructions were tweaked to make things better as well (Thanks, Rex!). Now around 250A I can watch the idler
arm on the dyno start to twist! So with the new generator setup I've uncovered some mechanical issues needing to be
fixed as I increment it up to 800A. I may be forced to go with a chain drive setup if I can't get the belt to stay within the
pulley limits. I'm not looking forward to that, so I'd rather fix what I have now.  Sure don't need the belt leaving the
vicinity while pushing amps. As expected, not much else got done this week due to setting up the dyno, which isn't very
thrilling to begin with. I've gotta go, more to do...
6/7 Well, another weekend sailed by. I found the motor drive pulley was closer than the rest, so I moved it out to be
equal with the rest, and added a diagonal cross brace between the motor ends to keep things stable there. I got to
300A today before I could pull past the generators limits. I have more debug to do on the AC hardware, something
may still be limiting my power capability. So a tad more checking to do there. As soon as I reach 500A, a split kit can
be shipped out, and when I reach 800A I can release Rob's Gen 2 system. The pipeline has been restricted to the
limitations of the dyno. I'm pretty tired writing this update, so if there's a few misspelled words, sorry!
6/9/09 More progress, got up to 400A on a controller today! After much debugging, a few more issues surfaced for
attention and a tweak in code on for generator. Part of the power control circuitry that was previously used on testing
power devices was merged with newer control circuitry from another project. In the process, current levels were
assumed preset to maximum values (>100A), but after testing, they were much less. This explains the generator giving
up at less than expected torque. The other problem is jitter on the speed control loop destabilizing the generator
making it easier to yield to the applied torque of the WarP 9. Speaking of torque, the key was too small for the WarP 9
(not used) and I noticed the pulley has moved on the shaft! Ok, getting real close to shipping out some hardware. And
onward to 800A motoring current on the WarP9! Kudos to Rex for putting up with my many code changes over the last
week(s). More to do, but getting sleepy closing in on 10pm...zzz
2/28 With Pedro's system heading overseas, I can get back to building and testing things. I spent around 4 hours
wading through the paperwork and with many calls to FedEx to make sure I was doing things right. Problem there was
when I felt something wasn't right, I had to call back to get the right answer. They didn't have anything on the web to
indicate you were on the right trail. I had to spend much time guessing on what to do next, then end up getting booted
out of the system when you were idle for awhile!