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Post by kris on Sept 20, 2022 15:27:39 GMT
So I got a few hours to play today and I wired up the exciter wire correctly. Bulb lights when I flick the switch on. I started the engine to spin the alternator, the bulb dimmed but didn’t extinguish the voltage reading across the battery dropped if anything. The bulb flickered dimly with engine running. The brammer belt isn’t helping it seems to stretch. So I took a link out to tighten it again. I started the engine again to see if any different, exactly the same bright until engine starts then flickers dimly. So am I not spinning the alternator fast enough? I’ve got about a 8-9 to 1 ratio on the pulleys. Or is there not enough voltage to excite the alternator? The pulley on the alternator did get warm in only a short space of time, which would suggest not spinning fast enough.
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Post by Telemachus on Sept 20, 2022 15:42:51 GMT
So I got a few hours to play today and I wired up the exciter wire correctly. Bulb lights when I flick the switch on. I started the engine to spin the alternator, the bulb dimmed but didn’t extinguish the voltage reading across the battery dropped if anything. The bulb flickered dimly with engine running. The brammer belt isn’t helping it seems to stretch. So I took a link out to tighten it again. I started the engine again to see if any different, exactly the same bright until engine starts then flickers dimly. So am I not spinning the alternator fast enough? I’ve got about a 8-9 to 1 ratio on the pulleys. Or is there not enough voltage to excite the alternator? The pulley on the alternator did get warm in only a short space of time, which would suggest not spinning fast enough. The belt may be slipping. Turn on ignition, light comes on with a bit of field current. Start engine, alternator accelerates until the small current from the bulb is enough to generate some current in the field diodes which increases the magnetic field which increases the current which increases the magnetic field and thus the voltage on D+ rises to the battery voltage, light goes out. BUT all that comes with a massive increase in mechanical load on the belt, it slips, so alternator slows down, insufficient field current, insufficient generated power, D+ voltage drops, light comes on. Rinse and repeat (rapidly). Propensity for the belt to slip depends on the pulley ratios and in particular, a small alternator pulley diameter means belt slip is more likely. Higher engine rpm means for a given load there is less force on the belt so less propensity to slip. SO, start the engine with the alternator switch off. Rev the engine as fast as you can, THEN switch on the alternator and see if that is better. And or, adjust the regulator voltage right down so that load on the alternator is less. But if any of these things prove effective, you will need a better way to drive the alternator that doesn’t slip. Oh and you quote the pulley ratio (which is quite high ) but not the engine rpm. Alternators typically need around 4000 - 6000 rpm to work well. Maximum rpm 15,000 to 20,000 or so, depending on the model.
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Deleted
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Post by Deleted on Sept 20, 2022 15:59:01 GMT
I used to run the alternator belt on my JP round the flywheel against the ring gear as the pulley behind it didn't drive the alternator fast enough. It meant I could lose the Brammer belt which was needed as I couldn't pas a normal belt over the flywheel, it did mean a very long belt though.
Something to think about if you can't get it working.
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Post by Deleted on Sept 20, 2022 16:08:56 GMT
If the LFP (Valence) batteries are full then they won't want any more charging.
I don't know what alternations (sp) were made to the alterator but if it has been adjusted to charge LFP and the battery is full...
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Post by kris on Sept 20, 2022 16:34:57 GMT
If the LFP (Valence) batteries are full then they won't want any more charging. I don't know what alternations (sp) were made to the alterator but if it has been adjusted to charge LFP and the battery is full... this is still only connected to the starter battery.
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Post by kris on Sept 20, 2022 16:38:02 GMT
So I got a few hours to play today and I wired up the exciter wire correctly. Bulb lights when I flick the switch on. I started the engine to spin the alternator, the bulb dimmed but didn’t extinguish the voltage reading across the battery dropped if anything. The bulb flickered dimly with engine running. The brammer belt isn’t helping it seems to stretch. So I took a link out to tighten it again. I started the engine again to see if any different, exactly the same bright until engine starts then flickers dimly. So am I not spinning the alternator fast enough? I’ve got about a 8-9 to 1 ratio on the pulleys. Or is there not enough voltage to excite the alternator? The pulley on the alternator did get warm in only a short space of time, which would suggest not spinning fast enough. The belt may be slipping. Turn on ignition, light comes on with a bit of field current. Start engine, alternator accelerates until the small current from the bulb is enough to generate some current in the field diodes which increases the magnetic field which increases the current which increases the magnetic field and thus the voltage on D+ rises to the battery voltage, light goes out. BUT all that comes with a massive increase in mechanical load on the belt, it slips, so alternator slows down, insufficient field current, insufficient generated power, D+ voltage drops, light comes on. Rinse and repeat (rapidly). Propensity for the belt to slip depends on the pulley ratios and in particular, a small alternator pulley diameter means belt slip is more likely. Higher engine rpm means for a given load there is less force on the belt so less propensity to slip. SO, start the engine with the alternator switch off. Rev the engine as fast as you can, THEN switch on the alternator and see if that is better. And or, adjust the regulator voltage right down so that load on the alternator is less. But if any of these things prove effective, you will need a better way to drive the alternator that doesn’t slip. Oh and you quote the pulley ratio (which is quite high ) but not the engine rpm. Alternators typically need around 4000 - 6000 rpm to work well. Maximum rpm 15,000 to 20,000 or so, depending on the model. I think I sorted the belt out by tigtenjing it. It didn’t seem to be slipping. The brammer belt does stretch though. I think I wasn’t spinning it fast enough. I’ll give it ago tmw with more revs.
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Post by Deleted on Sept 20, 2022 17:05:50 GMT
Can we skip to the final bit to see if it all works? Feckin twat. Just come back later when he's finished if you're not interested.
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Post by Telemachus on Sept 20, 2022 17:14:58 GMT
The belt may be slipping. Turn on ignition, light comes on with a bit of field current. Start engine, alternator accelerates until the small current from the bulb is enough to generate some current in the field diodes which increases the magnetic field which increases the current which increases the magnetic field and thus the voltage on D+ rises to the battery voltage, light goes out. BUT all that comes with a massive increase in mechanical load on the belt, it slips, so alternator slows down, insufficient field current, insufficient generated power, D+ voltage drops, light comes on. Rinse and repeat (rapidly). Propensity for the belt to slip depends on the pulley ratios and in particular, a small alternator pulley diameter means belt slip is more likely. Higher engine rpm means for a given load there is less force on the belt so less propensity to slip. SO, start the engine with the alternator switch off. Rev the engine as fast as you can, THEN switch on the alternator and see if that is better. And or, adjust the regulator voltage right down so that load on the alternator is less. But if any of these things prove effective, you will need a better way to drive the alternator that doesn’t slip. Oh and you quote the pulley ratio (which is quite high ) but not the engine rpm. Alternators typically need around 4000 - 6000 rpm to work well. Maximum rpm 15,000 to 20,000 or so, depending on the model. I think I sorted the belt out by tigtenjing it. It didn’t seem to be slipping. The brammer belt does stretch though. I think I wasn’t spinning it fast enough. I’ll give it ago tmw with more revs. I don’t think the problem is just insufficient speed. The “positive feedback” of an alternator means that as rpm is increased from very low, at some point (depending on lamp current) the light will suddenly go out and the alternator will start charging. It is an instantaneous transition, not a gradual one. Once the light has gone out, in fact rpm can be reduced and the alternator will continue to work. I can’t think of a scenario other than a slipping belt to explain the behaviour - the alternator spins up then virtually stalls as it comes on line, repeating rapidly. With a small alternator pulley it can be quite hard to avoid belt slip. As I said, try running the engine fast first, then turn on the alternator.
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Post by Jim on Sept 20, 2022 17:16:09 GMT
Can we skip to the final bit to see if it all works? Feckin twat. Just come back later when he's finished if you're not interested. Get nurse to explain the joke to you...
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Deleted
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Post by Deleted on Sept 20, 2022 17:16:36 GMT
Wrong lamp wattage?
Eta proper alternator regulators like the Balmar offerings have multi stage belt protection ramp-up system.
I don't use rotary electrics for charging but if I did and the demand was likely to be high I think an adjustable or automatic setup would be wise.
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Post by Deleted on Sept 20, 2022 17:18:39 GMT
Feckin twat. Just come back later when he's finished if you're not interested. Get nurse to explain the joke to you... I hate crap jokes, yours are just as bad. You should both be blindfolded and shot.
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Post by kris on Sept 20, 2022 17:18:46 GMT
it’s five watts which I thought was enough?
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Post by Deleted on Sept 20, 2022 17:21:15 GMT
Get nurse to explain the joke to you... I hate crap jokes, yours are just as bad. You should both be blindfolded and shot. Why the blindfold? Are you afraid of seeing the fear in their eyes?
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Post by Jim on Sept 20, 2022 17:23:52 GMT
Get nurse to explain the joke to you... I hate crap jokes, yours are just as bad. You should both be blindfolded and shot. Grumpy old twunt. It's your's btw. Some of us take pride in our punctuation and wit.
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Post by Jim on Sept 20, 2022 17:25:44 GMT
I hate crap jokes, yours are just as bad. You should both be blindfolded and shot. Why the blindfold? Are you afraid of seeing the fear in their eyes? Nah, the ridicule. ελευθερία
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