Re: BGM Stator Failures
Posted: Thu Jul 01, 2010 6:46 pm
As I told you, I would like to keep you updated about our bgm stator plate R&D we are doing at the moment.
To give you the complete story and share our findings this will be a little bit more comprehensive. First I have to admit that the statement for the HP (=high power) was a little bit optimistic with all the different ignition components out there. We have used the power rates of the stators as some manufacturers do. So we have stated the highest power output we have achieved. Somewhere we still think this is right. On the other hand there is a lot of misunderstanding on electrics. If you tune an engine and it gives 20 hp, then you should be ‘allowed’ to state it gives 20 hp, if you have dynoed it. But if you sell the engine and the purchaser over gears it so much that you can’t achieve this readings, you may get the problem to explain…
If we get back to the bgm stator, we have used the Vespa Cosa winding of the coils for the HP version. We have done a prototype using a contact breakers back plate and riveted the Cosa coils to it. Like Mark has invented it back in the 80’s with P-range coils. This was a straight conversion and we were able to power bulbs connection which summed up to 120 W.
The main goal with the bgm stator plate back then, was to have reliable setup with high quality field coil and Pickup for ultra high reliability. This was a serious problem back then and you may like to check the chapter of the ignitions in the Sticky manual for that. And with lots of positive feedback on that, I am convinced we did sort of right.
For the lightning power output the conversion from 6 V to 12 V is the first important step to increase the efficiency. With a 35 W headlight beam at 6 V current the Ampere readings are roughly 5.5-6 A at the beam. This high reading gives high thermical losses at the loom, switches, connectors and so on. This is the reason for dimming at low revs. With increasing revs the heat increases further. With 12 V current you can cut back the A readings to the half. The loom and connectors are not as highly loaded AND the thermical losses are only 25%. This leaves more energy for the bulbs itself.
For a high power output the coils should have thick wire to the maximum possible for the dimensions of the coil. Fixed in stone by the ignition design. The HP state plate does this. While we were more than satisfied with the bgm stators on our personal bikes, we take the forum critics very serious. We started to fiddle around to see what happens when the setups of the ignition systems were altered. We found the regulator have a massive effect on the performance.
We have looked into the DC conversion of the bikes as well. These ‘DC conversions’ use AC power output to run the main and rear light as well as the speedo bulb. While you use the DC power to run the horn/buzzer and the stop light. The problem WAS that you have to use a battery to have DC power saved for running at low revs. Despite of this, this gives top performance with no dimming of the lights when you use the horn or brake. Not a problem, when dimming is only recognized with the speedo bulb. But definitely frightening if you use the brakes running your Lambretta in the dark at mountains or in the rain on a motorway.
At the moment we are still testing different stator plate mods and have developed our own bgm regulator.
This gives AC and DC power output. We hope to have it produced later this year. But sadly these things are not as easy. The aim is to have the AC power output with a SENSE function. For this you have to do (on a first sight) strange connection from the power IN to the AC power out. But this connection is used to tell the regulator how much load is on the consumer. If the readings drop the regulator gives more for it. A bridge direct at the regulator is fine. This regulator should enable you to convert all bikes to DC, regardless if a AC or DC loom is used.
But back to the plot: We found that the magnetism of the flywheel has an important effect for the power output. Our fav stator for the testing (before we started) was a NOS old AF/Ducati flywheel. Sadly this gave the worst reading of all. Due bad storage it has lost nearly all its magnetism. Doh! We have different grades of magnetized flywheels for testing the stator plate now. We are considering this in our testing. We won’t state the power output in the future because of the given reasons. But it seems that a high power output reading isn’t the goal. Instead we are aiming to realize a solution that gives not max power output readings, but high output over the complete rev range. Especially low down the rev range. So like a good tuned engine!
For the stator plate test, I would like to ask the people who reported about the faulty stators to get in contact to me. I will give a free exchange plate. It would be nice to see one and use it for our tests.
I will keep you updated.
cheers philipp
To give you the complete story and share our findings this will be a little bit more comprehensive. First I have to admit that the statement for the HP (=high power) was a little bit optimistic with all the different ignition components out there. We have used the power rates of the stators as some manufacturers do. So we have stated the highest power output we have achieved. Somewhere we still think this is right. On the other hand there is a lot of misunderstanding on electrics. If you tune an engine and it gives 20 hp, then you should be ‘allowed’ to state it gives 20 hp, if you have dynoed it. But if you sell the engine and the purchaser over gears it so much that you can’t achieve this readings, you may get the problem to explain…
If we get back to the bgm stator, we have used the Vespa Cosa winding of the coils for the HP version. We have done a prototype using a contact breakers back plate and riveted the Cosa coils to it. Like Mark has invented it back in the 80’s with P-range coils. This was a straight conversion and we were able to power bulbs connection which summed up to 120 W.
The main goal with the bgm stator plate back then, was to have reliable setup with high quality field coil and Pickup for ultra high reliability. This was a serious problem back then and you may like to check the chapter of the ignitions in the Sticky manual for that. And with lots of positive feedback on that, I am convinced we did sort of right.
For the lightning power output the conversion from 6 V to 12 V is the first important step to increase the efficiency. With a 35 W headlight beam at 6 V current the Ampere readings are roughly 5.5-6 A at the beam. This high reading gives high thermical losses at the loom, switches, connectors and so on. This is the reason for dimming at low revs. With increasing revs the heat increases further. With 12 V current you can cut back the A readings to the half. The loom and connectors are not as highly loaded AND the thermical losses are only 25%. This leaves more energy for the bulbs itself.
For a high power output the coils should have thick wire to the maximum possible for the dimensions of the coil. Fixed in stone by the ignition design. The HP state plate does this. While we were more than satisfied with the bgm stators on our personal bikes, we take the forum critics very serious. We started to fiddle around to see what happens when the setups of the ignition systems were altered. We found the regulator have a massive effect on the performance.
We have looked into the DC conversion of the bikes as well. These ‘DC conversions’ use AC power output to run the main and rear light as well as the speedo bulb. While you use the DC power to run the horn/buzzer and the stop light. The problem WAS that you have to use a battery to have DC power saved for running at low revs. Despite of this, this gives top performance with no dimming of the lights when you use the horn or brake. Not a problem, when dimming is only recognized with the speedo bulb. But definitely frightening if you use the brakes running your Lambretta in the dark at mountains or in the rain on a motorway.
At the moment we are still testing different stator plate mods and have developed our own bgm regulator.
This gives AC and DC power output. We hope to have it produced later this year. But sadly these things are not as easy. The aim is to have the AC power output with a SENSE function. For this you have to do (on a first sight) strange connection from the power IN to the AC power out. But this connection is used to tell the regulator how much load is on the consumer. If the readings drop the regulator gives more for it. A bridge direct at the regulator is fine. This regulator should enable you to convert all bikes to DC, regardless if a AC or DC loom is used.
But back to the plot: We found that the magnetism of the flywheel has an important effect for the power output. Our fav stator for the testing (before we started) was a NOS old AF/Ducati flywheel. Sadly this gave the worst reading of all. Due bad storage it has lost nearly all its magnetism. Doh! We have different grades of magnetized flywheels for testing the stator plate now. We are considering this in our testing. We won’t state the power output in the future because of the given reasons. But it seems that a high power output reading isn’t the goal. Instead we are aiming to realize a solution that gives not max power output readings, but high output over the complete rev range. Especially low down the rev range. So like a good tuned engine!
For the stator plate test, I would like to ask the people who reported about the faulty stators to get in contact to me. I will give a free exchange plate. It would be nice to see one and use it for our tests.
I will keep you updated.
cheers philipp