A 12-volt condenser is part of an automotive ignition system. The battery provides power to the primary side of the ignition coil, which in turn produces high voltages across the secondary windings of the ignition coil. The voltage from the secondary winding is fed to the spark plugs as required to start the engine. The purpose of the condenser is to protect this ignition system from stray voltages that can interfere with the efficiency of the ignition coil. It does this by functioning as an insulator between the stray voltages and the ignition system.
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Put on electrical safety gloves as part of the safety precaution necessary to protect yourself from electrical shock.
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Disconnect and remove the condenser from the associated circuitry. Ensure the condenser and all parts are dry since dampness may cause misleading results.
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Connect a megger across the condenser terminals. The megger will produce a high voltage as required to measure resistance of the condenser in megohms. Put the positive lead of the megger on the positive terminal of the condenser and the negative or ground end of the megger to the negative terminal of the condenser.
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Start up the megger. Select the 500-volt range using the voltage range dial on the megger. Be sure you are not touching the condenser while doing this step. You should get an initial reading of 10 megohms or more on the megohm meter located on the front panel of the megger. Within a few seconds, the resistance should increase to several hundred megohms as the condenser charges up. You should quickly obtain a stable resistance of infinity or at the highest level of the megohm meter. This high resistance will validate the condenser is functioning as an insulator because an insulator has infinite resistance. If the initial reading is less than 10 megohms or if the resistance doesn't increase significantly within a few seconds, this means the insulation in the condenser is failing and the condenser needs to be replaced.
What Does a Condenser Do for an Alternator?
Alternators produce an electrical field that can interfere with radio reception. An alternator condenser corrects this problem. Automobile alternators are necessary to recharge the car battery and to run the car electrical systems without using the battery.
Alternator
An alternator converts the mechanical energy of the engine into electrical energy in the form of alternating current. It makes this conversion by spinning wire brushes at high speed near copper coils to create an electrical field. The electrical current the alternator produces is the discharge of this field.
Condenser
The word condenser has been replaced largely by the word capacitor when referring to the type of device used as an alternator condenser. A capacitor or condenser has no moving parts. It consists of an insulator connected to two conductors.
Alternator Condenser
Alternator condensers are seen mainly in older automobiles. Modern car radios are designed largely with a built-in shield against alternator-generated static. When a condenser is used, one of the leads connects to the alternator and one connects to ground. When a difference in voltage exists between the leads, a field is generated. Excess energy stores in the insulator, shielding the radio from the interference that would otherwise be discharged.
