{"id":1020,"date":"2010-10-10T03:58:19","date_gmt":"2010-10-10T07:58:19","guid":{"rendered":"http:\/\/www.etotheipiplusone.net\/?p=1020"},"modified":"2010-10-10T03:58:19","modified_gmt":"2010-10-10T07:58:19","slug":"razer-revolution-end-menial-labor","status":"publish","type":"post","link":"https:\/\/www.etotheipiplusone.net\/?p=1020","title":{"rendered":"RazEr rEVolution: End Menial Labor"},"content":{"rendered":"

When we last left rEVolution, I was halfway through the process of turning my hands into bloody, tattered stumps. It’s a ritual that occurs with the construction of every hub motor (which means I went through it four times<\/em> to make the RazErBlades).<\/p>\n

And by all that I mean winding the motor. Here’s the end result, terminated for presentation.<\/p>\n

\"\"<\/a><\/p>\n

I ended up keeping the “split dLRK” winding style – making 6 teeth wound AabBCc and the other 6 aABbcC.\u00a0 They’re terminated in separate non-connected<\/em> star points on the underside. The leads are grouped by their respective phases – motor 1 is the classic white-red-black, and motor 2 gets yellow-green-brown.<\/p>\n

My patience deterioration is very clearly shown in the picture. I wound this motor starting from the Aa<\/em> side and proceeded counterclockwise. You can see a decay in the quality of windings and the neatness of layers right after the aA<\/em> phase on the left. Then by the last one, it’s all gone to hell.<\/p>\n

\"\"<\/a><\/p>\n

To maintain engineering rigor, I took measurements of the DC resistance of each phase. This will pretty much determine how much current the motor can ever pull.<\/p>\n

I proceeded to defenestrate engineering rigor (MITERS has very large ceiling-height windows, so this was easy) by scribbling the resistances hastily on the workbench. In dry-erase.<\/p>\n

From the picture, you can deduce that the C phase of motor #2 is about 10% short of turns. Yeah, I think I pretty much stopped caring by that point. The other phases should have 39 to 42 TPT, but I’m guessing 35 or less made it onto the last C phase if I’m lucky.<\/p>\n

\"\"<\/a><\/p>\n

Fit test!<\/p>\n

I tried giving the motor a test spin using a sensorless controller (essentially by bootstrapping off Melon-scooter), but neither half-motor exited the “starting” regime. This was concerning. Did I terminate them wrong? Wind something backwards just a little bit?<\/p>\n

A few minutes of diagnosis revealed that the motor was technically running smoothly, but the controller just didn’t increase throttle. Applying voltage to each half-motor in each combination of the 3 leads (i.e. A to B, A to C, B to C…) produced 6 identically spaced angular positions each time – which is indicative of correct winding, since that’s pretty much what your controller does anyway, just alot faster and without colliding alligator clips.<\/p>\n

I pretty much just declared it to be a fault of shitty sensorless aircraft controllers being unable to deal with inertial loads or high friction systems.<\/p>\n

Without a supply of hall sensors, I put the frame and motor away and started thinking about the other parts of the electrical system.<\/p>\n

\"\"<\/a><\/p>\n

EVs generally have 3 big components – motor, controller, and battery. With the latter two, you can shoehorn anything in as a motor<\/em>. With motor and battery, you can be a dumbass like me and control the vehicle with a mildly more civilized form of touching 2 wires together<\/a>. But without a battery, what am I to do – run the whole thing from a bag of lemons?<\/p>\n

Luckily for me, people have figured out how to stuff the equivalent of tanker-loads of lemons into lithium nanophosphate cells. Above is the 12S2P A123<\/span> DeWalt 36v Lithium pack during mid-assembly.<\/p>\n

I managed to find some terrifyingly wide copper braid this time, and I think the cells just look so much better<\/em> with them instead of the \\m\/etalpaxxx<\/a>‘ quadruple braid. The massive interconnects just scream this pack will dump enough amps to destroy you and everything you ever loved.<\/em><\/p>\n

\"\"<\/a><\/p>\n

Another serving of giga-braid later and the pack structure is complete. I decided to split the pack into 2 6S packs again for balancing purposes, but this time the pack isn’t two separate entities. Shane<\/a> supplied me with Real Legit JST-XH Connectors of Battery Balancing (+14, for pin count), or otherwise I would have probably resorted to 7 pin-header again.<\/p>\n

\"\"<\/a><\/p>\n

Bottleshrink returns once again, but this pack is so long<\/em> that I needed the midsections of 3 bottles to completely enclose it. Luckily, it fit 2 liter bottles fine, and I just pulled a few out of the recycling bin.<\/p>\n

\"\"<\/a><\/p>\n

A quick check of the cell levels revealed that these cells are in fact still quite healthy despite sitting for an unknown period of time.<\/p>\n

Of course, that all<\/em> went to hell on the first charge, and I had to spend an hour manually bringing each cell group up to full.<\/p>\n

back to motters<\/h1>\n

Given that the motor itself seems to be correctly wound, I surmised that all my problems would go away as soon as I added the requisite hall sensors to the slots.<\/p>\n

\"\"<\/a><\/p>\n

And here they are, temporarily CA’d in place as a soldering fixture. LRK-style motors need a physical 120 degree sensor arrangement, but I’ve always found cross-stator wiring work to be awkward. Therefore, like on the skatemotors<\/a>, I take the B sensor and flip it around for a 60 degree, every-two-slots layout.<\/p>\n

\"\"<\/a><\/p>\n

I secured a chunk of 6 pin cable to the access slot in the shaft using epoxy. At the same time, I elected to secure the phase leads to the other side of the motor. The whole epoxy-globbed mess was then introduced to my epoxy curing oven<\/span> fixture<\/span> implement<\/span> hair dryer hanging by its power cord from the ceiling.<\/p>\n

\"\"<\/a><\/p>\n

After the first round of epoxy set, I finished connecting the sensor wires. Unfortunately, I managed to break off the output pin of the B sensor… and so ended up having to install the opposite one anyway.<\/p>\n

Luckily, this design left plenty of space near the edge of the stator, so running the wiring all the way around the motor wasn’t as difficult.<\/p>\n

\"\"<\/a><\/p>\n

The sensors got their own layer of goop. I kept finding buckets of different epoxy fillers around MITERS – this is “cellulose” filler, which probably just means paper dust.<\/p>\n

It claimed to be less cancer-inducing than either the silica or phenolic microspheres, so I gave it a shot.<\/p>\n

\"\"<\/a><\/p>\n

After another hour or two of watching glue dry, I put the motor together. Here it is – Dual (Non-)Interleaved RazErMotor!<\/p>\n

But does it work?<\/p>\n

\"\"<\/a><\/p>\n

That’s a gooooooooood question.<\/p>\n

Using the Kelly KBS which sort of miserably failed at running Melon-scooter, I was able to briefly power up and spin the DNIR to full speed. Qualitative observation tells me that at least I didn’t get it that wrong<\/em>. The fact that it moved at all meant that I got the sensor arrangement correct for the “split dLRK”. Now, for this test, I just paralleled the equivalent phases of each half-motor. Once I put together the RazerDEC board, each motor will be powered by its own controller, but triggered from the same sensors.<\/p>\n

The speed was visually in the “correct” range and it started and ran smoothly with no signs of improper winding or termination.<\/p>\n

that is, until it started sounding like a moped.<\/h1>\n

Oscilloscope diagnosis of the sensor outputs showed that every mechanical revolution, all 3 sensors were blanking. This caused confusion for the controller for a split second until the sensors outputted a valid signal again.<\/p>\n

Well, this is disappointing. The sensors – which, mind you, I had JUST encased permanently in a cellulose-epoxy matrix – seem to be having power issues once per mechanical revolution. I’m fairly certain it’s power, anyway, because there is no physical way for all 3 sensors to read the same field orientation the way they are set up.<\/p>\n

This actually means it shouldn’t be hard to fix – my guess is that somewhere, a bare solder joint is nicking the metal can once per revolution and causing a short between sensor 5 volts and ground. A further test to confirm (or dispel) this would be to look for dips in the 5 volt line during each revolution.<\/p>\n

In the mean time, there’s no pics of it running, therefore it didn’t happen.<\/p>\n","protected":false},"excerpt":{"rendered":"

When we last left rEVolution, I was halfway through the process of turning my hands into bloody, tattered stumps. It’s a ritual that occurs with the construction of every hub motor (which means I went through it four times to make the RazErBlades). And by all that I mean winding the motor. Here’s the end […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,66,62],"tags":[],"class_list":["post-1020","post","type-post","status-publish","format-standard","hentry","category-project-build-reports","category-razer-revolution","category-reference-posts"],"_links":{"self":[{"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=\/wp\/v2\/posts\/1020","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1020"}],"version-history":[{"count":1,"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=\/wp\/v2\/posts\/1020\/revisions"}],"predecessor-version":[{"id":1021,"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=\/wp\/v2\/posts\/1020\/revisions\/1021"}],"wp:attachment":[{"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1020"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1020"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.etotheipiplusone.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1020"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}