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Post by rune75 on Mar 27, 2013 4:33:42 GMT -5
I have a Sym Mio 50 whit a 6 pin CDI. It has both DC and AC connected. If I pull the
fuse it of course loses the DC current, but it doesent make any difference. The scooter runs just fine without it. From what I've read these CDI's run on DC
or AC, not both.
Anybody know the function of the DC connection ?
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Post by alleyoop on Mar 27, 2013 12:42:42 GMT -5
How did you test the CDI for DC current being fed?
Alleyoop
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Post by rune75 on Mar 27, 2013 13:17:47 GMT -5
How did you test the CDI for DC current being fed? Alleyoop The DC current is being fed from the ignition switch. I can see it on the wiring diagram I found online. I also measured it in/on the plug when I unplugged the CDI. |
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Post by gy6girl on Mar 27, 2013 14:29:54 GMT -5
Aren't all CDI's technically both AC and DC?
I am pretty sure that they both convert one to another for one reason or another.
They call them DC or AC because of what electricity goes into them.
While looking for a DC CDI, I read that they convert to AC for the spark.
I am pretty sure that the AC CDI's convert to DC for some of the digital electronics. They have to.
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Post by alleyoop on Mar 27, 2013 14:42:19 GMT -5
Rune75, To verify what system you have, TURN THE KEY TO THE ON POSITION and take either a 12V LIGHTER TESTER or your Volt meter and TOUCH THE BOTTOM WIRE(POWER FEED WIRE SHOWEN IN THE PICTURE) on the TWO PLUG connected to the CDI. If Light Tester and it lights or Volt meter registers 12V you have a DC system, which means the BATTERY is feeding the CDI the Voltage. If nothing off that wire then you have a AC system which means the STATOR is feeding the CDI the Voltage. Also if its a DC system it will NOT run if the battery is bad or disconnected. Alleyoop  |
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Post by rune75 on Mar 27, 2013 16:01:55 GMT -5
It runs just fine without the battery connected.
My CDI has 6 wires and they are in random order:
Ground
Signal from pickup
Killwire/shutoff wire
Coil feed
AC power
DC power
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Post by alleyoop on Mar 27, 2013 16:05:58 GMT -5
Then you have an AC system, THE AC POWER your referring to is your KILLSWITCH WIRE. What that does is GROUNDS the CDI and will not SEND send juice to the COIL. The two bottom wires are both ground wires on the 4 plug.
Take a picture of your CDI WITH THE WIRES PLUGGED IN.
Alleyoop
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Post by rune75 on Mar 27, 2013 16:25:12 GMT -5
If you google 'Sym Mio servicemanual' you will find and be able to download a pdf of the servicemanual.
On the last pages you will find a wiring diagram where you can see how the CDI is wired.
All 6 wires come from different places. Killswitch and AC are separate.
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Post by alleyoop on Mar 27, 2013 16:54:17 GMT -5
I just looked at the diagram that is the second ground wire going to the batteries ground.
Alleyoop
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Post by RapidJim on Mar 27, 2013 20:32:27 GMT -5
Aren't all CDI's technically both AC and DC? I am pretty sure that they both convert one to another for one reason or another. They call them DC or AC because of what electricity goes into them. While looking for a DC CDI, I read that they convert to AC for the spark. I am pretty sure that the AC CDI's convert to DC for some of the digital electronics. They have to. It does not convert DC to AC, it is really a pulsating DC, DC voltage turning off and on. The CDI does not convert anything. The voltage regulator does that. The term AC or DC CDI is referring to the type voltage that is required as an input to allow the cdi to operate. You can look at it this way, your house works on AC voltage and your car works on DC voltage. Jim |
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Post by woowilly on Mar 28, 2013 0:49:40 GMT -5
There's quite a bit of conversion going on in both types of CDI when they're use...
A DC CDI can operate without a battery connected, the 470 uF capacitor on the dc-dc converter input will get a pulse of 12 volts from the regulator as the stator magnets go 'round. ( gotta spin 'em 'round fairly fast though.) this will allow the DC-DC converter to run enough to charge the high voltage capacitor in the cdi and the 12v pulse will also put enough of a charge on the filter capacitor on the 5 volt supply line in the CDI for operating the low voltage CDI stuff. ( My harley runs with no battery or battery eliminator, it has a DC CDI. the spark is weak and under load causes one cylinder to misfire though. However it was good enough to limp home and the next day replace the battery that developed a totally open cell.)
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Post by alleyoop on Mar 28, 2013 1:55:43 GMT -5
The R/R has nothing to do with your CDI. It feeds your battery and some accessories like your ENRICHER. There are no wires from the R/R that go to the CDI. The CDI either is fed by the Stator which means you have a AC CDI or directly from the BATTERY which means you have a DC CDI. If you have a DC CDI and you disconnect your battery or it is bad or take it out your CDI will not get power and you will not have SPARK and therefore your motor will not run.
Alleyoop
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Post by rune75 on Mar 28, 2013 4:00:08 GMT -5
I just looked at the diagram that is the second ground wire going to the batteries ground. Alleyoop Nope. Only one wire is connected to ground and that is the green one, marked G. The wire next to it, marked B (black) goes to the main/ignition switch and provides DC power. |
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Post by rune75 on Mar 28, 2013 6:41:08 GMT -5
Go to page 190 in the service manual, and you will see how it's hooked up.
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Post by Abscooters on Mar 28, 2013 10:35:07 GMT -5
Very interesting, I wonder if the black is a battery backup in case the stator fails?
Other than the extra green are the pin configuration/wire colors the same as alleyoop's pic above?
Try leaving the black one plugged in and disconnect the black w/red and see if it still runs.
I'm going to have a dc cdi bike open today. I'll have to compare wire colors.
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..BAD TO THE BONE..
