AVR SS350 | Mcpherson Controls

The SS350 (KP-SS350) is an Automatic Voltage Regulator (AVR) and direct replacement for the Marathon SE350, used in brushless generator systems. It controls the generator output voltage by regulating the excitation current, maintaining stable voltage under varying load conditions.

The SS350 accepts a sensing input voltage of 85–135V AC at 50/60 Hz (jumper selectable) and a power input of 180–265V AC. Output voltage is a maximum of 37V DC at 110V AC input or 73V DC at 220V AC input, with a continuous current of 3.5A and intermittent current of 7A for 10 seconds. Resistance range is 15–100 ohms.

Voltage regulation accuracy is less than ±1% with 4% engine governing. External voltage adjustment of ±5% is available via a 1kΩ trimmer, or ±10% with a 2kΩ trimmer. The unit includes internal EMI suppression filtering and under-frequency protection with the knee point factory-set at 54–61 Hz for 60 Hz systems and 45–51 Hz for 50 Hz systems. Operating temperature range is -40°C to +60°C.