#garfield Logs

Mar 08 2022

12:37 AM miss0r: rue_mohr: Have you got haft a day to beat me with a clue-bat? :)
12:52 AM rue_mohr: ?
12:52 AM rue_mohr: I'm an insomniac, I have till 1am
12:53 AM miss0r: rue_mohr: I have no idea what your time-zone is, but whatever that leaves I'll take :)
12:54 AM miss0r: I've scrapped the arduino driver for one major reason: The point in time where it measures the peak current over my shunt resistor is not correlating with the switching output. which spells trouble
12:54 AM miss0r: so at the moment I am building a circuit with a UC3845, driving a mosfet gate driver, which drives a mosfet. This is all nice and simple.
12:55 AM miss0r: I have this thing running somewhat properly. But to optimize it a bit I need to figure out how to calculate the windings in my transformer, as I think this is the bottleneck now. It charges realy fast/fast enough for me anyway up to around 400 volts, but then slows to a crawl for the remainding 50 volts.
12:57 AM miss0r: I've found this calculator on the interwebs, that, in theory, should allow me to type in my known data and get a result for the windings I need to make: https://www.utmel.com/tools/flyback-transformer-design-and-calculator?id=40
12:57 AM miss0r: But the outputted data from this does not make sense to me.
12:58 AM miss0r: it tells me that Turns Ratio Primary to Secondary Winding 1, Nps1: equals 103. but it also tells me that the primary winding number should be 2.12 and secondary should be 151. That calculates to a turn ratio of about 71. What am I not understanding here?
12:59 AM miss0r: You think you can shed some light on the situation?
01:03 AM miss0r: My transformer is made from N87 material: https://www.tdk-electronics.tdk.com/download/528882/71e02c7b9384de1331b3f625ce4b2123/pdf-n87.pdf The specific core is: B66365G0500X127 as seen in https://docs.rs-online.com/5e4a/0900766b813c0f2a.pdf
01:12 AM miss0r: rue_mohr: Have I scared you off with my wall of text? :)
08:28 AM rue_bed: hah, I dozed off right away, rare
08:29 AM rue_bed: the voltages on a flyback are all funny
08:30 AM rue_bed: its more about limiting the voltage on your switch during flyback
07:03 PM Tom_L: evening
07:08 PM rue_shop3: pulling the beepers out of about 20 smoke alarms from work
07:08 PM rue_shop3: (old ones )
07:09 PM Tom_L: piezo?
07:13 PM rue_shop3: yp
07:13 PM rue_shop3: wow, like 60% of them had spider nests in them
07:13 PM Tom_L: heh
07:13 PM Tom_L: probably not much else to salvage from them ehh?
07:21 PM rue_mohr: no, there is a transistor that looks tempting but is too much work
08:31 PM rue_shop3: units 8 thou mm
08:32 PM rue_shop3: .2032
08:42 PM Tom_L: .2032
08:42 PM Tom_L: wow i need better glasses
08:42 PM Tom_L: cold has my head all screwed up
09:04 PM rue_shop3: if I slap my chuck the offset dissapears
09:29 PM Tom_L: so if you need the offset, don't slap it?
09:29 PM Tom_L: bearing play?
09:34 PM rue_shop3: I think the head bearings need to be tightened
09:34 PM rue_shop3: but
09:34 PM rue_shop3: I dont think thats it
09:35 PM rue_shop3: completely
09:35 PM rue_shop3: the chuck is tight
09:35 PM rue_shop3: I finished the peice,, but I dont really have a way to check it
09:37 PM Tom_L: got an indicator?
09:37 PM Tom_L: of course i don't know how big this piece is
09:38 PM Tom_L: center the shaft and measure how off the other half is
09:39 PM Tom_L: one side will be under, the other will be over
09:39 PM Tom_L: maybe crude...
09:44 PM Tom_L: or put it in a v block and measure it that way
09:46 PM rue_mohr: oh I'll shoot ya images
09:46 PM rue_mohr: ok I see
09:52 PM Tom_L: yeah i'd like to see it
09:53 PM rue_mohr: hold on..
09:55 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1230127.jpg
09:55 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1230128.jpg
09:57 PM rue_mohr: trickey project
09:58 PM Tom_L: is the hole offset too?
09:58 PM rue_mohr: I circled the two
09:58 PM rue_mohr: they are centered togethor
09:58 PM rue_mohr: so no
09:59 PM Tom_L: are the slot and the hole concentric?
09:59 PM Tom_L: or is the slot offset too
09:59 PM rue_mohr: I only added the slot as a transition region
10:00 PM rue_mohr: its just a relief
10:00 PM Tom_L: mm
10:00 PM Tom_L: did you get an ECO for that???
10:00 PM Tom_L: :)
10:00 PM rue_mohr: oh mind those two vert lines 8 thou apart, thats his center lines
10:00 PM Tom_L: k
10:01 PM Tom_L: so it's got an .008" offset
10:01 PM rue_mohr: yep, note how I suggested the relief be in the hole on my first try
10:01 PM rue_mohr: then I realized it was the other view
10:01 PM Tom_L: wtf is it for?
10:01 PM rue_mohr: aligning a transmission
10:01 PM Tom_L: a crooked one
10:01 PM rue_mohr: not sure
10:02 PM rue_mohr: he needs two
10:02 PM rue_mohr: he had a tool and die guy make ... 6 now
10:02 PM rue_mohr: and WTF
10:02 PM rue_mohr: one looks completely hand filed
10:02 PM rue_mohr: even _ME_ looking at it, its like NO, NO , NO
10:03 PM rue_mohr: somehow my housing side length was out
10:03 PM rue_mohr: but I think its ok
10:03 PM rue_mohr: I should have doublechecked before doing the final cutoff
10:04 PM Tom_L: so why is it .008 off center but the od offset is .006?
10:04 PM rue_mohr: different ODs
10:05 PM Tom_L: .006 on one side and .010 on the other
10:06 PM Tom_L: that's .004 offset
10:06 PM rue_mohr: ODs are .6190 and .6230
10:06 PM rue_mohr: so, 4 thou there
10:07 PM rue_mohr: hmm
10:07 PM Tom_L: but the centers are off too?
10:07 PM Tom_L: that's kindof a fucked up drawing
10:07 PM rue_mohr: the .6190 is supposed to be 8 thou off from the .6230
10:08 PM rue_mohr: hmm, is this not adding up?
10:08 PM Tom_L: i'd have to look closer when i'm not tired
10:08 PM rue_mohr: I didn't cross check it
10:09 PM rue_mohr: but I didn't use the surface differences either
10:09 PM Tom_L: and one of the OD isn't visible
10:09 PM rue_mohr: the two ods are thre
10:09 PM Tom_L: the top left arrow
10:10 PM rue_mohr: at the botom .623 at the top .6190
10:10 PM rue_mohr: oh
10:10 PM rue_mohr: same numbers
10:10 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1230129.jpg
10:11 PM Tom_L: leave it to dodge to do something like that
10:13 PM Tom_L: so this goes on the block and tranny housing cases
10:13 PM Tom_L: because they misaligned something
10:13 PM rue_mohr: yep
10:13 PM Tom_L: or they're trying to fit something that wasn't intended
10:14 PM rue_mohr: I think the truck has a questionable history
10:15 PM Tom_L: is this a one off?
10:18 PM Tom_L: is it a hot rod?
10:18 PM Tom_L: V10...
10:18 PM Tom_L: viper?
10:19 PM Tom_L: what else has a V10 in it?
10:20 PM rue_mohr: its a big pickup
10:20 PM rue_mohr: he's making his own engine controller for it
10:20 PM rue_mohr: he already did that is
10:20 PM Tom_L: it would be easier to ream the holes
10:20 PM rue_mohr: I wrote him a state machine to work out the crank position
10:21 PM Tom_L: and put a bigger pin in
10:21 PM rue_mohr: not sure
10:21 PM Tom_L: access might be an issue
10:21 PM rue_mohr: I dont even know how he worked this all out
10:21 PM Tom_L: i'll call him and ask :)
10:24 PM Tom_L: anyway, if you have a V block and a flat surface you should be able to measure it pretty easy
10:25 PM rue_mohr: ok
10:26 PM rue_mohr: dont you have to get in there?
10:28 PM Tom_L: huh?
10:52 PM rue_bed: I presume its two blind receivers
10:53 PM Tom_L: hmm
10:53 PM Tom_L: could be but usually at least one goes thru
10:54 PM rue_bed: hmm
10:54 PM Tom_L: that way if something gets stuck...
10:54 PM Tom_L: there's a way out
10:54 PM rue_bed: k
10:54 PM rue_bed: falling asleep
10:55 PM rue_bed: better have supper
10:55 PM Tom_L: yeah, i'm calling it a night too
10:56 PM rue_mohr: oh still cooking ,ugh
11:28 PM rue_mohr: ah, got these esp-01s 's working