Does anyone have a schematic for a simple four pin HEI ignition module from 1970's+ ignition systems. They appear to contain an SCR and a pair of diodes and resistors.
Pickup Coil connects to two terminals and battery and induction coil primary the other two, mounting screw provides a ground connection.
Original type mounted to the distributor plate on GM cars and others and was ~1/4 round shape - I want to adapt it to a motorcycle that has pickup coils mounted remote from the modules.
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:Does anyone have a schematic for a simple four pin HEI ignition module :from 1970's+ ignition systems. They appear to contain an SCR and a :pair of diodes and resistors. : :Pickup Coil connects to two terminals and battery and induction coil :primary the other two, mounting screw provides a ground connection. : :Original type mounted to the distributor plate on GM cars and others :and was ~1/4 round shape - I want to adapt it to a motorcycle that has :pickup coils mounted remote from the modules.
Most 70's era street bikes would run from the 12V battery supply so you would have to buy a kit suitable for this power supply. I don't know where you are but here is one kit
If your bike doesn't have a battery which is chaarged from an alternator/generator then it will probably use an generator supply winding to produce the input voltage. In this case a simpler kit can be used
The bike is 80's runs from the battery. They call it a CDI but it isn't - runs from 12V with no HT generator coil - the module just has
4-5 components in it (potted in black goo) induction coil is ~3.5 ohms.The advance is managed in the pickup coil end of things.
The dealer wants $200 per module and I need two for a bike worth ~$1,000. The 70's style module for cars runs about $40 now (was $15) each.
Physically too large even if it was suitable. The originals are only one cubic inch with mostly heat sink.
turned this up in my searching
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but
[snip]Doesn't take much to make a CD Ignition, see....
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
Thanks. What is the theory of operation? What I have now, connects one side of the coil to the battery and the other side to the ignition module. In that circuit, D3 D2 would stay forward biased if the coil goes to B+.
This circuit is supposed to dump a largish negative spike to the coil?
What kind of voltage does the transistor have to stand off?
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Let's see, Q1 charges L1 thru D1, then when Q1 lets go, L1 charges C1 through D1 and D2. After a quarter sine wave, current reverses and the diodes drop out, leaving C1 more or less charged inbetween cycles. (Without D1, L1+C1 could oscillate, the current being carried through D2 and D3; D1 produces a clean break after exactly a quarter wave.) This puts a considerable voltage on Q1, something like, let's see, 5A in 5mH is 62.5mJ so... about 353V. When the transistor turns on again, C1 is discharged through D3 and the ignition coil, so it will need to handle whatever the peak current is (Ice > 10A), and the peak voltage (Vceo > 400V).
If possible, a 2ms one-shot should be used to charge the inductor, since V =3D L * dI/dt --> 12V =3D 5mH * 5A/2ms. This circuit can repeat as soon as the inductor is done whipping around, which takes about 0.1 ms.
The lynch pin of this circuit is the transistor, which must be quite beefy. If nothing else, a stout base drive must be provided, which I suppose isn't hard to do in an automotive environment. hFE =3D 5, if not 3 or 2, is probably the kind of drive needed for a relatively high Vce, ampy transistor in deep saturation. (Incidentially, t_stg will probably end up something absurd like, 5us, 10us if you don't pull as much current out of the base- but this delay isn't at all critical, as long as t_f is reasonable, it won't burn up much switching power. It's switching at audio frequencies after all.)
Yup!
Tim
Here's a link to the Delta Mark 10 CDI.
-- Dave M MasonDG44 at comcast dot net (Just substitute the appropriate characters in the address)
All of the control circuitry is not shown.
(1) Transistor turns on (2) When current in inductor reaches 5A, transistor turns off, dumping energy into capacitor (~350V) (3) When transistor turns on again, capacitor dumps into ignition coil (conventional ratio) firing plug; and inductor charging begins again.
Works great... I've used it to saw Plexiglas ;-)
I used 500V BVCEO (NPN) devices.
There are probably Power MOSFET's now that would work better... HV NPN's have lousy beta, requiring beta correction circuits in the current sensing.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
Thanks, I'll give it a try.
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and
Thanks. This isn't something I can use on this bike - too large. I did build two of these myself in the 70's one went on a BMW motorcycle and the other a Land Cruiser.
I think Jim's circuit is more viable given the components we have today - and my size constraints. (although I could run one inverter to boost voltage for both spark coils then just double up the SCR cap circuits).
Appreciate the feedback, and I'll save the schematic
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Thoughts coming back to me... with a conventional ignition coil (from a car points-type system), peak primary current was 11 Amps! So size your MOSFET accordingly.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
Coil resistance is 3.5 ohms, that's only 4 amps.
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When hit with 350V ?:-)
...Jim Thompson
-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
Oh.
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Yep! You missed that the cap acquires charge when the inductor dumps :-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
Whatever you do, it will be specific to that make, model and year. Do you know that most 4-cylinder MC have two ignition coils (and no distributor)? (Some have 4, and many V-twins have two.) Many 1970s and later MC have some variation of CDI already, do you know what it currently has? What kind of sensor coils does it use (some still used points)? Does it have speed variable timing, some do, and some don't.
Of course I know all that.
Make model and year - just a simple switch with no timing advance.
Duh? Like I haven't counted the coils by now? Two coils, two pickup coils, four cylinders.
CDI is stretching a point - they call it CDI but the module is less than a cubic inch - no room for a cap. Only one three terminal device with no inductors, one tiny ceramic cap, and a few diodes - values unknown. In the 80's CDI meant DC/DC converter and a box of ~10 cubic inches charging up a 1 uf to 350V to discharge through an ignition coil. This gizmo doesn't have that many parts - more like a transistor switch goosed by a pickup coil as a magnet passes by,
No points - pickup coils.
No variable timing - that's done mechanically. Magnets are on a centrifugal advanced plate, pickup coils are stationary.
It appears as if they just use a transistor switch. The coils have 12 volts to one side of the primary as long as the ignition is on.
When the motor is turning, the other side of the primary goes to ground briefly. Two identical coils, two identical modules, each alternately fires on each revolution of the crank - one wasted spark per two cylinders.
I have an ignition module from a 1984 bike -same plug/receptacle but the circuitry suggests there is an electronic advance using an RC network - larger module, more parts, but it still works in the 1980 bike. Suggests to me that there is a primative advance circuit in the module. But the 84 module still contains mostly passive components with three small capacitors and more diodes and resistors.
Unlike outboard motors - the bike doesn't have a high voltage winding on the charging circuit - everything works from 12 VDC.
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