example
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| example [2022/01/01 14:49] – created spark | example [Unbekanntes Datum] (aktuell) – Externe Bearbeitung (Unbekanntes Datum) 127.0.0.1 | ||
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| + | ====== Example ====== | ||
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| + | I want to introduce how a CDI can be developed. The following CDI was developed in 2016. But it's just a BETA-Version and has never reached a final status. So please read and enjoy. It is not recommended for recreation. | ||
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| + | Its project name was VSCDI3. | ||
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| + | {{ : | ||
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| + | {{ : | ||
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| + | ===== motivation ===== | ||
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| + | The VSCDI3 was created to work with Vape A70-3 and A70-5. It should have an easy structure with not to much components. The adjustment timing should be soft to work with nearly every engine with a moderate rev level. | ||
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| + | ===== circuit diagram ===== | ||
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| + | The basic design is close to the [[st_reference|ST reference]] design, but with an added negative wave handling and a modified signal shaping. | ||
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| + | {{ :: | ||
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| + | ==== Negative wave handling ==== | ||
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| + | The branch with R1, R2 and D4 is limiting the negative waves. A first Version had R1 = 10 k (and R2 empty), but this created to much heat dissipation and the SCR get out. | ||
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| + | The following values were obtained after measurement: | ||
| + | * U_Peak = 800 V | ||
| + | * I_Peak = 0,08 A | ||
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| + | A current of 0,08 A does not sounds much. But the Heat power loss is be calculated with: | ||
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| + | P = I² x R = (0,08 A)² x 10 000 Ω = 64 W | ||
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| + | And 64 W are a huge heat load! So next time do the math and the measurement first. After a few more test R1 and R2 was dimensioned to 560 W each. | ||
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| + | ==== Signal shaping ==== | ||
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| + | Again a branch with D6 and R3 is handling the negative signal waves. | ||
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| + | The positive signal waves are shaped with "the rest" between H5/white and the SCR gate. | ||
| + | With vary C1 and C2 the signal timing can be customized. | ||
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| + | ==== Capazitor ==== | ||
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| + | A standard size of the Capazitor C3 is 1 uF. But to get more energy at low revs it was contemplated to use 1,5 uF. By the way this are just thoretical approaches, no driving test have been made. | ||
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| + | ==== SMD elements ==== | ||
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| + | This elements were used for the SMD version with the pictures above. | ||
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| + | ^Element^Value^Comment^ | ||
| + | |R1|560|3 W| | ||
| + | |R2|560|2 W| | ||
| + | |R3|330|-| | ||
| + | |R4|4,7 k|-| | ||
| + | |R5|100|-| | ||
| + | |D1...6|SL1M|-| | ||
| + | |Q1|STM TS820|-| | ||
| + | |C1|4,7 uF|Elko| | ||
| + | |C2|10 uF|Elko| | ||
| + | |C3|1 / 1,5 uF|-| | ||
| + | |C4|10 nF|-| | ||
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| + | Note: The SCR ON CR708AG does not work with this scheme. | ||
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| + | For a THT version the should be used UF4007 for the diodes and a TIC106M for the SCR | ||
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