Testing a generator

[emto]

Might be a stupid question, but.
When testing a generator on an NC30 for the 50V output, what exactly do you do?
Obviously the bike is running when you disconnect the block connector, but where do you put the multimeter probes for getting the readings? Is it between each pin or do you have the black probe earthed to the frame?

Thanks in advance.

[Neosophist]

Might be a stupid question, but.
When testing a generator on an NC30 for the 50V output, what exactly do you do?
Obviously the bike is running when you disconnect the block connector, but where do you put the multimeter probes for getting the readings? Is it between each pin or do you have the black probe earthed to the frame?

Thanks in advance.

disconnect the block connector before you start the bike.

call each of the yellow pins A B and C

measure between the pins

AB
BC
AB

not the frame.

hope that helps.

[emto]

Thanks Neo, thats what I thought, just did'nt want to blow something.

[Neosophist]

no worries.

Make sure you have your multimeter set to AC volts not DC. (if it is a manual meter it will usually be 200 / 750 or 300 / 700 etc)

200v setting is fine, it will only kick out around 50v for this test.

[speedy231278]

Is there a figure considered 'low'? I was trying to do the thermostat today, decided to remove the fairing bracket with the alternator connector, and one of the wires parted company with the connector due to corrosion. Was a massive effort to get the thing apart, and it turned out to be that all the spade ends were corroded to buggery, and I'm surprised I got anything at all. All the generator side female connectors were so badly corroded I scrapped the ones that were still connected, but the loom side male ones cleaned up lovely, apart from the one that wouldn't come out as the connector had melted slightly due the excess heat causes by the extra resistance. In fact, it had more or less welded the two together..!

Anyway, measured the resistance between them all and each pair was 0.6 ohms, which tallies with the 0.1 to 1 that the Haynes says. Out of curiosity, I measured the voltage output as well. At idle, they were all around 12V, at 5K rpm, they measured mid 40s, +- a couple of volts. It was a little hard to decide which figure for each as the figures bouinced around by a few volts, I suspect that being a cheap, crap meter it can't cope with fluctuating values very well. I did write the figures down, but the piece of paper is in the garage with the bike which I'm about to take out and hope it doesn't die before then end of the Bank Holiday! At the battery at 5K it was producing 13.5 to 13.6, although slightly oddly it spiked higher when I shut the throttle (less demand from the ignition?). Not overly happy with that figure, it's just in spec, but right at the low end....

[Neosophist]

Is there a figure considered 'low'? I was trying to do the thermostat today, decided to remove the fairing bracket with the alternator connector, and one of the wires parted company with the connector due to corrosion. Was a massive effort to get the thing apart, and it turned out to be that all the spade ends were corroded to buggery, and I'm surprised I got anything at all. All the generator side female connectors were so badly corroded I scrapped the ones that were still connected, but the loom side male ones cleaned up lovely, apart from the one that wouldn't come out as the connector had melted slightly due the excess heat causes by the extra resistance. In fact, it had more or less welded the two together..!

Anyway, measured the resistance between them all and each pair was 0.6 ohms, which tallies with the 0.1 to 1 that the Haynes says. Out of curiosity, I measured the voltage output as well. At idle, they were all around 12V, at 5K rpm, they measured mid 40s, +- a couple of volts. It was a little hard to decide which figure for each as the figures bouinced around by a few volts, I suspect that being a cheap, crap meter it can't cope with
fluctuating values very well. I did write the figures down, but the piece of paper is in the garage with the bike which I'm about to take out and hope it doesn't die before then end of the Bank Holiday! At the battery at 5K it was producing 13.5 to 13.6, although slightly oddly it spiked higher when I shut the throttle (less demand from the ignition?). Not overly happy with that figure, it's just in spec, but right at the low end....

it seems ok.

Make sure the contacts for the genny are good and everything is soldered to proper clean spades.

Ive trimmed the wires back for the genny on bikes before quite a way to get back to decent wire. Flux it up and solder to get a nice join. Fully insulate everything and solder the spades.

make sure your earths are good too.

remember some shitty wire / contact will make more resitstance, add heat and rob power.

[speedy231278]

Yeah, everything was crappy and there's not a lot of spare to play with. I polished up the big earth conector that is bolted to the frame at the same point as the fiaring bracket, and polished the bracket and frame too. My soldering iron os crap, so I didn't bother trying to solder the spades in the end and just crimped them for the time being. I think a more sensible solution will be to replace the wires from the stator to the connector, but that's not going to be a quick and easy job, and I need the bike tomorrow and Monday and I'm not going to risk starting something that leads to even more trouble! At the very least, I'll revisit the spades next time I'm back with a soldering iron and proper connectors rather than the Hafrauds crimp ones that have a very short crimping area. I'd like to get the other male spade cleaned up better, but it's welded into the connector because of the heat, so I might end up just ditching the connectors altogether and use spades on their own. Topo much messing around for right now. Anyway, the results:

From not having been ridden, the battery measured 12.6V off, 12.6V idle and 13.5V at 5K (well, OK, I gave the bike a few minutes to warm up after checking at idle as I don't like revving a stone cold engine).

The alternator output was 13.0/13.0/13.0 at idle and 42.7/46.0/44.8 at 5K.

The resistance between each pair was 0.6 ohms.

After a 15 mile ride not venturing too far from home, the battery read 12.88 off, 13.0 idle and 13.6 at 5K.

I'll measure everything again when I get the spades sorted out. If it's still about the same, I'll investigate the output at the reg/rec end and see if there's any significant loss between the alternator and reg/rec or the reg/rec and battery. I don't think I'll be replacing the stator at about £420, bit of a pain they don't market the wire run on it's own, even if it would be a solder job at the stator end.

Just one thing, I'm not entirely unconvinced that I didn't mix up two of the wires. All being AC and the same output, would I be correct in assuming that it doesn't actually matter which output is where on the reg/rec as none are different to the others?

[Neosophist]

You can put the 3 yellow wires in any direction :)

12.8 is fully charged