AVR voltage regulator for the Hahn & Sohn HDE 9300SS3 diesel generator

AVR (Automatic Voltage Regulator) is an electronic regulator that controls the alternator excitation current and thereby maintains the generator's output voltage at a constant level. Without a functioning AVR, the voltage fluctuates according to the load - it drops when an appliance is switched on and rises when the load is reduced. Stable voltage is essential for the safe operation of sensitive electronics, chargers, pumps with variable frequency drives, or measuring equipment.

• This regulator is supplied as an original replacement part for the Hahn & Sohn HDE 9300SS3 diesel generator with a single-cylinder, four-stroke 499 cm³ diesel engine and 230/400 V, 50 Hz output. It fits into the alternator compartment thanks to the segment-shaped (fan-shaped) housing, which follows the contour of the generator cover, and is secured with two bolts through mounting holes with metal bushings.
• The printed circuit board is completely encapsulated in resin. The encapsulation protects the electronics against engine vibrations, moisture, and dust, all of which are common during generator operation. The regulator includes an adjustment trimmer for fine-tuning the output voltage and a heat sink for the power component. Connection is provided by six wires in two plug-in connectors, so replacement requires no soldering or modification of the wiring.

Why customers choose it

• Original part specifically for the HDE 9300SS3 model - no uncertainty about compatibility
• Encapsulated electronics resistant to vibration, moisture, and dust
• Plug-in connector connection - replacement without soldering or modifying the wiring
• Adjustment trimmer for fine-tuning the output voltage

Practical tip

Fluctuating voltage, consistently excessive or insufficient voltage at the sockets, and flickering lights while the generator is running are most commonly caused by a faulty AVR. Before replacing the regulator, also check the alternator brushes and the condition of the connectors - a damaged or oxidised contact can cause the same problems as faulty electronics. It is advisable to keep a spare AVR available for generators used as backup power sources for a home or business, because without it the generator cannot be safely operated under load.

Key features

• Automatic Voltage Regulator (AVR) for a generator
• Designed for the Hahn & Sohn HDE 9300SS3 (6-6.5 kW, 230/400 V, 50 Hz)
• Segment-shaped (fan-shaped) housing for installation in the alternator compartment
• Resin-encapsulated printed circuit board
• Heat sink for the power component
• Adjustment trimmer for fine-tuning the output voltage
• 6 wires in two plug-in connectors
• 2 mounting holes with metal bushings

Use / Installation / Operation

Before replacement, switch off the generator, allow it to cool, and disconnect the battery. The regulator is located in the alternator compartment beneath the cover. Disconnect both plug-in connectors, loosen the two mounting bolts, and remove the regulator. Install the new part in the same position and connect the connectors according to the wire colours - the connectors are shaped so that they cannot be interchanged.

After installation, start the generator without load and measure the output voltage. If it differs from the rated value, adjust it using the adjustment trimmer, always in small increments while continuously monitoring the voltage. Perform the adjustment at the rated engine speed. We recommend having both replacement and adjustment carried out by a service technician, as the work is performed close to live electrical circuits.