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| vtsteam:
Would a capacitor across the meter lines (if long) reduce noise? I think that's the problem with long lines. These ESC's sense RPM via back emf in the motor to adjust timing. The input lines also see large swinging currents and back emf there from long lines can confuse the ESC. Or I think that's the reasoning..... Maybe it's not a problem, though since Simon has had it running already.... |
| John Rudd:
Well if it was me, I'd lengthen the three leads to the motor, keeping them to a minimum( remove the existing leads from the speedo and attach the longer ones, no joints!). Then place the ammeter shunt in series with one of the battery leads on the esc, the sense lines from the shunt go to the remote meter, and wind both thru a ferrite donut(one or two turns should suffice to reduce the effects of any noise going to the meter), but as it's an analog meter,I think the effects of any noise reaching it will be negligible ..... |
| S. Heslop:
--- Quote from: vtsteam on July 16, 2014, 12:11:01 PM ---Would a capacitor across the meter lines (if long) reduce noise? I think that's the problem with long lines. These ESC's sense RPM via back emf in the motor to adjust timing. The input lines also see large swinging currents and back emf there from long lines can confuse the ESC. Or I think that's the reasoning..... Maybe it's not a problem, though since Simon has had it running already.... --- End quote --- Currently it's just a temporary setup with components cable tied wherever they'll fit. I'm gonna be building a wooden box to stick the batteries, shunt, and fusebox in (still thinking about how to keep the batteries cool when inside of a box, but I need to try and waterproof this whole thing). But with longer cabling that might become a problem, but i'll worry about that when it happens I guess. The skateboard wheels arrived today so I took a little break from taking a break and machined stuff up. Didn't have too much of a problem turning the rubber. As you can see, its fairly low. I really mucked up my measurements, but it's not too much of a concern since I can just make a thicker washer on the bottom to move it back up. It's raining over this way though (at least it cooled down!) so i'll probably give it another break before making the new washer. I'm thinking I might drill 2 more holes on that bar that holds the spring though, and go with two springs. I guess I want the tension to be so much that the contact roller only slips in the event of a complete stall, and the leverage of the arms really reduces the pressure of the spring where it touches the wheel. |
| vtsteam:
It's been raining here, too, Simon. Can't wait to see your new rig working! :coffee: :coffee: |
| S. Heslop:
It's alive! I think it might send me back in time if I can pedal up to 88mph. Definitely needs some tidying up. I think I do too! It's just typical that the day (or few days) you don't bother to shave you end up bumping into everyone you haven't seen for a few years. People seemed pretty interested in the bike though, despite how silly it currently looks. I doubled up the springs holding the wheel down. I think I might add a third since there was a bit of slipping, although at this point i'm a little worried about over-loading these bearings. The tyre on the idle wheel got flung off, which says to me that the wheel couldn't spin so freely, perhaps because of the load. The top bearings are 69012, 12mm inside, 24mm outside diameter, which is fairly thin. I might try boring the holes a size bigger to fit a 28mm OD bearing that can take about double the load of the current ones according to the website i'm buying bearings from. Also with the enormous spring pressure the idea of using a break cable to release the arms from contacting the wheel seems kind of hopeless. Fortunately the motor turns fairly freely when not running, and doesn't cause any noticeable resistance. Still, i'm quite pleased that it's actually moving now. I'm just a little concerned about how it's going to hold up in the long run. I'll need to tart it up a bit before I can take out down to the cycle path for a stress test though. |
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