How to Install a Generator Voltage Regulator

A close up on a generator.
  • 2 hours
  • Intermediate
  • 250
What You'll Need
Voltage Regulator
AC/DC Generator
Fine sandpaper

A generator voltage regulator is needed to maintain a constant voltage within an AC or DC generator. While functioning, the engine within a generator works at different speeds according to the output that needs to be produced. An over-worked engine could heat up and produce surges that can be detrimental to the generator. A voltage regulator is mostly used within automobiles to keep the battery from overcharging and malfunctioning.

Step 1 - Check the Generator

Check if your generator is functioning prior to installing the regulator. Also, check the condition of the battery since it is an integral part of the system. Wiring between a generator, regulator, and battery is often prone to corrosion which can be removed with fine sandpaper. Before you remove any wires from their connection, tag them so that you can reconnect them. The generator has to be polarized before testing the regulator. Connect the positive terminal of the battery to the generator’s armature to polarize it. Remove the battery after this step. Although some manuals state that the regulator needs to be polarized it actually just means the generator since regulators are not polarity sensitive.

Step 2 - Choose a Regulator

Make sure that the regulator you use is suitable for the generator. The amount of voltage that your generator produces should fall into the range that the regulator can control. A popular range for a regulator is from 6 to 12 volts. Most regulators have the amperage and voltage marked on them for easy identification. Do not assume that the higher the voltage indicated on the regulator, the better it is for your generator and battery. If you have an internal regulator, it implies that your regulator is mounted within the alternator and it cannot be removed or replaced. If the regulator malfunctions, you will need to reinstall an entire alternator.

Step 3 - Understand AC Generators and Regulator Wiring

Although most alternators come with an in-built regulator, some do have an external regulator. The ground terminal of the battery has to be disconnected before working with the generator or the regulator. The regulator will have three wires. You will have to connect the two smaller wires to the alternator. The alternator usually has markings on it that say F and R. Connect F to where it says 1 on the regulator and R to where it says 2. Sometimes both the alternator and regulator markings say 1 and 2 or the regulator says F and R instead of the alternator. Simply remember the respective connections. Connect the big wire to the battery. Make sure the wiring in all circumstances is done accurately since any misconnection will damage your regulator and generator.

Step 4 - Understand DC Generators and Regulator Wiring

There are only three main wires that need to be taken care of within this system, the circuit breaker, current regulator, and the voltage regulator. Connect wire F of your regulator to the generator’s field wire, connect A is to the generator’s armature, and attach BATT to the positive terminal of the battery. BATT is usually brown/yellow, F is yellow/green, and A is mostly brown (bear in mind that these colors are subject to change according to the make of the device).