What is alternator ripple test?
What is alternator ripple test?
Alternator AC ripple – without ECM control. The purpose of this test is to check the rectification of the alternator output voltage, where the alternator output is not regulated by the Engine Control Module (ECM).
What does it mean when an alternator has excessive ripple?
Before computers and networks in vehicles, an alternator that was producing AC voltage or ripple through the electrical system would cause flickering lights and maybe an ignition problem. Today, excessive ripple voltage can cause communication issues with networks and communication DTCs in multiple modules.
How do you check AC ripple on alternator?
A multimeter can read AC voltage and can be used to test for ripple. The alternator should be replaced if AC voltage of more than 50mV is detected (in some cars as much as 100mV is acceptable). A dead or weak battery can throw off a ripple test, however, so you must make sure the battery is fully charged.
How do you measure ripple voltage?
Select the “AC Voltage” by turning the dial on the front to the picture of an oscillatory wave. Bring the probes into contact with the circuit that has the ripple voltage. The multimeter will only measure the AC component of the signal — i.e., the ripple voltage.
What causes voltage ripple?
Ripple voltage means the amount of AC voltage that appears on a DC voltage. The main reason for the ripple voltage is that the converter converts the AC voltage into a DC voltage, but the AC voltage cannot completely eliminate. The ripple voltage shown in Figure 1 is low frequency ripple voltage.
How do you increase ripple voltage?
An electronic filter with high impedance at the ripple frequency may be used to reduce ripple voltage and increase or decrease DC output; such a filter is often called a smoothing filter.
How much AC voltage does a car alternator produce?
A fully charged battery should read over 12.6 volts. The actual output voltage produced by the alternator will typically be about 1-1/2 to 2 volts higher than battery voltage. At idle, most charging systems will produce 13.8 to 14.3 volts with no lights or accessories on.
How many volts should an alternator put out at idle?
14.2 volts