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.