Question

What is the primary purpose of a capacitor (condenser) in a magneto ignition system?

Answer

The capacitor prevents arcing across the breaker points and helps accelerate the collapse of the magnetic field in the primary coil. This rapid collapse induces a high voltage in the secondary winding, producing a strong spark at the spark plug.

Explanation:

The capacitor in a magneto ignition system has two critical jobs:

1- Prevents arcing across the breaker points

When the breaker points open, electricity wants to keep flowing.

Without a capacitor, that electricity would jump across the gap between the points, causing:

. Arcing (spark at the points)

. Burning and pitting

. Rapid wear and failure.

The capacitor absorbs that energy, preventing arcing.

2- Makes the magnetic field collapse faster.

This is the most important part for spark production.

When the points open:

. The current in the primary coil stops

. The magnetic field collapses.

The faster the magnetic field collapses, the stronger the voltage induced in the secondary coil.

That high voltage is what fires the spark plug.

The capacitor acts like a '' shock absorber’’ for electricity.

It protects the points AND helps create a strong spark.

If the capacitor fails:

If OPEN:

. Heavy arcing at points

. Burnt contacts

. Weak or no spark

If SHORTED:

. No voltage buildup

. No spark at all

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