Operation Manual

MARATHON SE350 VOLTAGE REGULATOR

WARNING: To prevent personal injury or equipment damage, only a qualified service technician

should install, operate or service this device.

IMPORTANT: DO NOT megger or high-pot the generator while the regulator is connected.

DO NOT high-pot the regulator.

VOLTAGE ADJUST:

A screwdriver adjustable potentiometer adjusts the generator output voltage. Adjustment clockwise

increases the generator output voltage.

STABILITY ADJUST:

System stability is the ability of the generator to respond to load transients. Decreasing the stability

makes the generator less sluggish and faster to respond to load transients. If the stability of the regulator

is decreased too much, the generator will tend to hunt under steady state conditions. A screwdriver

adjustable potentiometer adjusts the system stability. Adjustment clockwise increases the stability.

Increasing the stability increases the response time of the generator. Conversely, decreasing the stability

decreases the response time of the generator.

V/HZ ROLL-OFF FREQUENCY SELECTION

The roll-off point is the frequency where the generator voltage starts to decrease. This reduces the

Kilowatt load to the engine, which allows the engine to recover in speed under any load transient

condition. Use jumper to select 50 Hz or 60 Hz. The screwdriver adjustable potentiometer sets the roll-

off frequency from 54-61 Hz in the 60 Hz setting or from 45-51 Hz in the 50 Hz setting.

The SE350 has the roll-off point preset to 58 Hz in the 60 Hz mode and 48 Hz in the 50 Hz mode. To

change the roll-off point, adjust engine speed to the desired rated speed. (50 or 60 Hz). Set the voltage to

the desired setting at rated speed. Adjust engine speed to the desired roll-off point. Turn the

potentiometer counterclockwise until the voltage starts to drop off. Then adjust the potentiometer

clockwise until the voltage returns to rated. Re-adjust engine speed to rated speed.

EXCITER POWER CIRCUIT:

Connect the regulator wire F+ to the generator

F+ or F1 field terminal. Connect the regulator

wire F- to the generator F- or F2 field terminal

SENSING / POWER INPUT CIRCUIT:

Input power and sensing is achieved through

terminals 3 and 4. The voltage input requirement

of the SE350 is 190 to 240V AC.

A 4 Amp 250V – 5x20 mm fuse is supplied with

the re

ulator.