TT91-1 Automatic Voltage Regulator

About this part

Sensitive loads such as computers, inverters and motor drives depend on a steady voltage. The regulator is a small, inexpensive board that protects everything downstream of the generator.

When to replace it

• Output voltage that is too high, too low or unstable
• No output voltage although the engine runs normally
• Lights flickering or voltage dipping as loads switch on
• A burnt or damaged board after a lightning strike or short

Before you order

Match the AVR to the alternator: sensing (single or three phase), excitation type (brushless or brush type), supply voltage and the physical mounting all have to suit. Note the wiring before disconnecting the old regulator.

Match the number stamped on the part you are removing, or the number in your engine or alternator manual, before ordering. Part numbers are shown for reference so the right replacement can be identified.

Questions