cosworth alternator???
15-06-2011, 08:49 AM
#2
20K+ Super Poster.
Yes, the thin blue wire from the dash charge warning light supplies + 12v to the "IND" terminal of the alt to excite the field windings and so start supply/producing lecky one turning.
If this is missing it will still kick in when revved to around 3500rpm, and stay kicked in until the engine stops, rev over 3500 again on restart and it charges again.
If the bulb/circuit is ok then it will charge as soon as turning with no revving to 3500.
The circuit supplies a live to the IND terminal, once charging this IND terminal changes state to live also putting out the bulb as it has two lives but no earth/negative.
tabetha
If this is missing it will still kick in when revved to around 3500rpm, and stay kicked in until the engine stops, rev over 3500 again on restart and it charges again.
If the bulb/circuit is ok then it will charge as soon as turning with no revving to 3500.
The circuit supplies a live to the IND terminal, once charging this IND terminal changes state to live also putting out the bulb as it has two lives but no earth/negative.
tabetha
15-06-2011, 01:02 PM
#4
Easiest way to check the blue wire circuit, is to simply see if the battery light illuminates when the ignition is switched on? If not then you have a break in the circuit.
Yes it supplies 12V via the bulb to the alternator, when charging the earth on alt then changes to live (Alternator power) and so two lives means the bulb extinguishes indicating to the driver all is well!
As said if revved high enough it will start charging so as you correctly suspect if it doesn't you have a problem with the item itself!
Martin
Yes it supplies 12V via the bulb to the alternator, when charging the earth on alt then changes to live (Alternator power) and so two lives means the bulb extinguishes indicating to the driver all is well!
As said if revved high enough it will start charging so as you correctly suspect if it doesn't you have a problem with the item itself!
Martin
15-06-2011, 02:06 PM
#5
Easiest way to check the blue wire circuit, is to simply see if the battery light illuminates when the ignition is switched on? If not then you have a break in the circuit.
Yes it supplies 12V via the bulb to the alternator, when charging the earth on alt then changes to live (Alternator power) and so two lives means the bulb extinguishes indicating to the driver all is well!
As said if revved high enough it will start charging so as you correctly suspect if it doesn't you have a problem with the item itself!
Martin
Yes it supplies 12V via the bulb to the alternator, when charging the earth on alt then changes to live (Alternator power) and so two lives means the bulb extinguishes indicating to the driver all is well!
As said if revved high enough it will start charging so as you correctly suspect if it doesn't you have a problem with the item itself!
Martin
so i've just tested it and with the ignition on i have power to the blue wire so my bulb must have gone in the clocks?
also alternator is fucked, its not charging at all even if i rev it up. i bought it of ebay a while ago and painted it up so it looks new and it does'nt work
15-06-2011, 02:37 PM
#6
thats what got me thinking my light has stopped coming on
so i've just tested it and with the ignition on i have power to the blue wire so my bulb must have gone in the clocks?
also alternator is fucked, its not charging at all even if i rev it up. i bought it of ebay a while ago and painted it up so it looks new and it does'nt work
so i've just tested it and with the ignition on i have power to the blue wire so my bulb must have gone in the clocks?
also alternator is fucked, its not charging at all even if i rev it up. i bought it of ebay a while ago and painted it up so it looks new and it does'nt work
15-06-2011, 03:25 PM
#7
20K+ Super Poster.
The easiest way is to simply probe the end of the blue wire with ignition on, it will read if passing current.
If the alternator has not been used for a LONG time, it may not have enough residual magnetism to start charging even when revved, that being the case simply use a small length of wire and hold one end on a live, alternator B+ for example and with the engine running touch it on the IND terminal where the blue wire goes, if it's working this will start it charging.
Make sure you're not confusing the also nearby "W" terminal, as they look the same, this is a single tapping from the AC wave of the alternator, and is a output of around 8V.
tabetha
If the alternator has not been used for a LONG time, it may not have enough residual magnetism to start charging even when revved, that being the case simply use a small length of wire and hold one end on a live, alternator B+ for example and with the engine running touch it on the IND terminal where the blue wire goes, if it's working this will start it charging.
Make sure you're not confusing the also nearby "W" terminal, as they look the same, this is a single tapping from the AC wave of the alternator, and is a output of around 8V.
tabetha
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15-06-2011, 05:13 PM
#9
The easiest way is to simply probe the end of the blue wire with ignition on, it will read if passing current.
If the alternator has not been used for a LONG time, it may not have enough residual magnetism to start charging even when revved, that being the case simply use a small length of wire and hold one end on a live, alternator B+ for example and with the engine running touch it on the IND terminal where the blue wire goes, if it's working this will start it charging.
Make sure you're not confusing the also nearby "W" terminal, as they look the same, this is a single tapping from the AC wave of the alternator, and is a output of around 8V.
tabetha
If the alternator has not been used for a LONG time, it may not have enough residual magnetism to start charging even when revved, that being the case simply use a small length of wire and hold one end on a live, alternator B+ for example and with the engine running touch it on the IND terminal where the blue wire goes, if it's working this will start it charging.
Make sure you're not confusing the also nearby "W" terminal, as they look the same, this is a single tapping from the AC wave of the alternator, and is a output of around 8V.
tabetha
i will double check its fitted to the correct terminal
16-06-2011, 06:38 PM
#13
20K+ Super Poster.
I remembered on my sapphy when sat for 7 months for engine/box sort I had no warning light, turned out it was slight corrosion on the little pads on the side of the bulb holder not making good contact with the wiring strip on rear of clocks.
tabetha
tabetha
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