What are the connections on an alternator?

Wiring Connections Since an alternator is connected to so many components, it exhibits a complex wiring system. The main wirings include the exciter wire, positive and negative cables. Exciter wire is connected to the L terminal of an alternator and is used to turn on the voltage regulator.

What is the L terminal on an alternator?

The alternator L terminal is the turn-on command for the charging system from the PCM. The PCM sends a 5V variable duty cycle signal to command the alternator charging voltage set point between 11 and 15.5V.

What does the W mean on an alternator?

The W terminal generally outputs an unrectified AC voltage, the frequency of which is proportional to the engine speed.

What does N mean on an alternator?

N. Neutral. Centre point of a Y-connected stator.

Which wire is the exciter wire on an alternator?

The wire is connected to the “L” terminal of the alternator. The exciter wire is used to turn on the voltage regulator. This wire, when unplugged, should have approx. 12.5 volts with the key on.

What does the R stand for on an alternator?

The “R” terminal or Relay terminal as it is sometimes called, provided some of the alternator’s output and was used to power electric tachometers, a dash light, hour meters, or other modern accessories. In some applications it was connected to the dash light to give notice if the alternator was failing to charge.

What are the different parts of an alternator?

The alternator’s stator (background), rotor (center), and rectifier (foreground). The primary components found within the alternator are the rotor, stator, and rectifier bridge. The rotor, which is the rotating portion of the alternator, consists of coils of wire (known as a field coil) behind opposing magnetic poles.

What kind of voltage regulator does an alternator need?

A typical alternator wiring diagram with an external electromechanical voltage regulator. Unlike electromechanical regulators, electronic regulators are solid-state without any moving parts. Electronic regulators use semiconductors (zener diodes and transistors) to control the alternator’s output.

What does a field terminal do on a car alternator?

Field or ignition terminal: Allows battery voltage from the ignition to flow to the alternator’s field coil during startup. Electronic voltage regulators have been used on many cars since the mid 1970s. Refer to the diagram below if you’re working on three-wire connections.

How does an alternator work in a late model car?

Many late-model vehicles use the engine computer, which is often referred to as the powertrain control module (PCM), to control alternator output. Most modules use an internal driver to turn the alternator’s field circuit on and off. An example is the General Motors (GM) Electrical Power Management (EPM) system.