 history lessons and used cardboard crowns to denote grammatical concepts such as nouns, adjectives, and verbs.Heh, it's interesting that you found this thread. I have had your website bookmarked for a long time. Yeah, I've now blown up the controller twice. I think this makes my average about 60% since I've successfully tested with no blow ups like three times and blown it up twice. Luckily this last time was just a transistor, gate resistor, and a few diodes. I'm using $25 surplus 200A IGBTs right now so that explosions are less sad.
I ordered a 50A 800V three phase rectifier off of ebay and used it connected to 240V single phase as my power source. Since I had precharge capacitors installed they were able to smooth the voltage to about 339V at rest. Unfortunately I never got to testing how much voltage fluctuation I was getting. However, I was only testing a 2HP motor unloaded so I doubt that the amperage was too high. I did have an oscilloscope running at the time. I put a probe on one of the three phase outputs to the motor while testing. I could see really large spikes on the output. They looked very short, perhaps like 1us. Here is where I wish I really wish I had video because all I can go on now are vague recollections after the fact. I'm not sure if the spikes were because A. I somehow managed to use IGBTs with no freewheel diodes. I doubt this because any reasonable half bridge should have them but I'll check B. using a rectifier would have caused the input voltage to be very unstiff and maybe that caused some issues C. I had way too long of a connection between the capacitor bank and the bus bars. I knew that was naughty but was hoping to get away with it. One thing is sure though, I had way too much inductance on the input side of the controller. D: Maybe my leads from driver to IGBT are too long. I mean, the wires are like 2.5" or something but maybe that's still too much. Or maybe something was getting induced on the lines. I might be able to shorten the leads even more.
Regrettably I didn't test for many of my guesses above. It blew up before I could. Well, it's fixed again and I'll keep at it.
Now, two years later, I'm running closed loop vector control, and have racked up almost 30k miles!
It's great to see other people take on a such a project. I wish you luck.
It's my first post, and I'm not allowed to post URLs yet =( You can google etischer and find my electric vehicle webpage.
This could also be why you were seeing large voltage spikes on the scope.
Yes, that's my guess too. I've since shortened the links and I think I'll try to make them even shorter. I know that the less distance and inductance between capacitors and bus bars the better. Chalk this one up for knowing better and trying it anyway...
Are your leads cable?
May I suggest using flat bar from the caps to the IGBTs, I know its a pain to fabricate but it will kill the inductance.
BTW etischer, I haven't kept up. Didn't know the AC was up and running. Nice!
I was using bars across the IGBTs. The batteries where connected through a contactor to the busbar. The capacitors, though, were connected to the bus bar with 2 or 4 gauge wire. It was way too long too. What a recipe for disaster! I've since bought a 66uF 800V film cap that can handle 100Arms. It is now bolted directly to the bus bars. My calculations suggest that this should result in a total of about 15V ripple at 100Arms AC ripple current. However, I also got some 1500uF 450V elcos. I might try to get bars long enough to put one or two of those on the bar too. That will make the bar sort of long though. I suppose the real question now is, what sort of ripple might the busbars experience? If I run a motor up to 250Arms then what equations should I use for the AC ripple at the caps? From what I can gather it seems that the AC ripple of a three phase system should be approximately half of the Arms to the motor. This would give me about 125Arms at the caps at peak output. Additionally, I might want to clamp the ripple voltage to less than 15v so I'll need more caps because of that too. So, I think I'll need a bit more than just my 66uf film cap but maybe not until I start really loading the motor. I'm reading that elcos in the system were mostly used in VFDs because they input rectified mains voltage and thus have very ripply voltage input. A battery is very stiff and constant so it seems like tons of capacitance is no longer needed. Instead, the caps in that case are just to deal with the ripple current and to decouple the IGBTs from the batteries.
I have a ton of PDFs about this whole situation but I certainly wouldn't reject suggestions either directly or for other PDFs or books I might want to read.
That's pretty impressive looking... I like it!
Make sure your bus bars don't rub through the vinyl insulation on your capacitors! You might also verify the vinyl insulation is rated for your bus voltage.
Looks great MrBigh!
How did you end up bending those curves on the bus bars?
- Latest available (Revised)
- Original (As enacted)
This is the original version (as it was originally enacted).
18In section 1(2) of the Scottish Land Court Act 1938 for " The Superannuation Acts 1834 to 1935 " substitute
“The principal civil service pension scheme within the meaning of section 2 of the Superannuation Act 1972 and for the time being in force”
and for " those Acts apply to persons in the permanent" substitute
“that scheme applies to persons employed:Wedding favors - any ideas?
I'm having trouble deciding what to do for wedding favors? Any ideas?
Wedding favors are totally optional. Guests typically don't notice if favors aren't given. If you decide to do them, I suggest doing something that is edible (cookies, smores kit, chocolate/candy, etc) - otherwise, many times, favors get left behind. If you do something non-edible, do not put your name/wedding date on it (unless it were on a tag/packaging). Think about things that you would love to receive as a wedding favor if you were the guest - a deck of cards? Mini plants? Candles? Chocolate? Also, choose something that you would still be able to use if extras were left behind at your wedding.
Otherwise, save the money and skip them.
Thanks for the advice and I'll look at the website!
Personalized hand sanitizer or anything edible or drinkable.
I was thinking about personalized hand sanitizers especially with the pandemic going on. I saw some cute ones on etsy.
Check wedding favors.com I did and they were cheaper.
I'm doing colored pretzels and heart shaped pralines. I picked something edible. Don't stress out about it. You will find something nice.
It’s ok to skip. Only offer favors if you really want to. If you do, choose something edible or they’re usually left behind/thrown out. Ideas: cookie, cake pop, candy bar or popcorn bar (except during Covid), chocolate truffle, etc.
It's ok to skip favors. Many people leave them behind, even edibles. Save your money and pit toward food/drink/entertainment that guests will remember.
If it fits your style and theme or decor, then do so, but if not it’s not required.
Thank you! Something edible seems easy and less stressful!
Thanks! I'll take this into consideration.
Thanks. My venue does have a chocolate fountain and a dessert station, so I probably won't have to feel obligated to get wedding favors.
Chiming in with another: SKIP.
We skipped, nobody noticed.
Half the time, they get left behind, someone's got an allergy, doesn't have a yard, doesn't drink, whatever... So... eh.
Most of our favors are edible i.e. candy & s'mores kits, I wanted to have something that's useful or edible since I didn't like the idea of offering something that would be thrown out or collect dust on a shelf. Don't spend a lot & look for something that can be eaten, many times the centerpieces can double as a favor in itself (mine will be, I don't want to keep those).
<filename>CYHelper/CYRuntimeHelper.h<gh_stars>10-100
//
//  CYRuntimeHelper.h
//  CYHelper
//
//  Created by Lancy on 26/11/12.
//
//

#import <Foundation/Foundation.h>
#include <execinfo.h>


@interface CYRuntimeHelper : NSObject

+ (void)printCallStackWithCount:(NSUInteger)count;

@end
I’am a very bitter Kenyan because looking at the ganeral situation here in Kenya I feel more people needs to follow the suite and board the plane to the Hague. I’am a journalist by profession and during the time chaos broke out I was on the ground in paticular Kibera covering