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Title: Alternator (excited???) Post by: Ed on May 17, 2005, 02:56:32 AM Hello,
I fitted a 120A alternator, with the exciter input and a diode to prevent it backfeeding to ignition. the alternator doesnt seem to work at the moment as my volt guage shows only 10Volts. is my excitor wire not right? is the dioide polarity sensitive and perhaps I got it in the wrong way? I only have this wire plus the power battery cable going to the alternator. any ideas? Cheers Ed Title: Re: Alternator (excited???) Post by: smithy on May 17, 2005, 04:36:14 AM hi ed, whats the condition of your voltage regulator. is this a new alternator? you can pull the regulator out and check the bushes for wear.
dean Title: Re: Alternator (excited???) Post by: Ed on May 17, 2005, 04:51:52 AM Hi Dean,
it's brand new, so im assuming should work OK. Cheers Ed Title: Re: Alternator (excited???) Post by: Dr_Terry on May 19, 2005, 06:08:34 AM Hi Guys.
Ed, did I hear you ask if a diode was polarity sensitive ? Yes it is. That's what a diode is, it only allows current in one direction. Dr Terry. Title: Re: Alternator (excited???) Post by: smithy on May 19, 2005, 09:03:05 PM hey ed, dr terry is spot on . from what i remember the diode included in the wiring kit you got has a small black ring at one end, i cant remember which way i goes but check the manual that glenn supplied with the kit it mentions which way it sits.
hope this fixes it dean Title: Re: Alternator (excited???) Post by: Ed on May 19, 2005, 09:27:26 PM Hi Dr terry and Dr dean,
thinking about it now, of course the diode would be polarity sensitive, otherwise it wouldnt stop the feedback current! thankyou for the advice, I may also place a diode on my IGN2 (Start) circuit to stop the coil current backfeeding to the starter relay circuit when released to the ON position (since the coil remains powered up I wouldnt want the starter relay to remain powered up as well). thanks again, I'm getting a handle on things with your help. Ed Title: Re: Alternator (excited???) Post by: Woodzy on June 12, 2005, 10:43:09 AM hi fellas,
am a tad confudled with the blocking diodes you mention. most alternators have 2 terms, a bolt for the battery (or ammeter) and the exciter terminal power is fed thru the ign switch ON possie thru the GEN/ALT telltale lamp on down to the little push on term on the alternator, ususally lableled D+. As the alternator is still, the light is on, once the donk starts and the alt sharts to charge it raises the voltage out the D+ term and the indicator lamp goes out. The diode would definitely prevent the excitation. Title: Re: Alternator (excited???) Post by: Woodzy on June 12, 2005, 10:45:33 AM ok
who turned off the spillchucker.... Title: Re: Alternator (excited???) Post by: Ed on June 14, 2005, 08:47:09 PM Woodzy, I ended up wiring to the terminals labelled L and S. L for Lamp and S for Voltage sensor. I still used a diode in the L circuit as this prevents backfeeding of current, normally the gen lamp does this. (i didnt want a gen lamp). Diodes work one way, so u just put in series in the direction u wish to prevent current flow or accordingly. What u say is correct, I was just trying to wire up this particular alternator incorrectly. This alt had a D+ terminal, L and S. I could only get it to work using the L and S terminals. hope this makes sense. it took me ages to work this out.... Cheers Ed |