Maritime English ETO IV_Pre Final

What causes low voltage in a generator?

• High speed and strong field

• Dry commutator

• Overload, low speed, improper brush setting

• Excess oil and dirt

What causes high voltage in a generator?

• Weak field

• Load imbalance

• Field too strong or speed too high

• Poor lubrication

What causes hot commutators?

• Cold brushes

• . Sparking under brushes, poor contact, nearby heat

• High resistance cable

• Wet coils

What causes sparking at the brushes?

• Clean commutator

• Overload, poor contact, rough commutator, weak field

• Short circuits only

• Wet surface

What causes low generator speed?

• High load resistance

• Overload, friction, improper brush setting

• Loose terminals

• Fast cooling

What causes high generator speed?

• Good maintenance

• Lubrication failure

• Forward brush setting, open field, excessive field resistance

• High humidity

General care of generator includes:

• Running at high RPM always

• Keep clean and dry, oil bearings, maintain governor

• Overloading occasionally

• Adding fuel to the brushes

Monthly generator check-up includes:

• Changing lights

• Checking load, lubrication, governor, bearing temperature

• Checking voltage only

• Washing cables with water

In the bright lamp method of synchronization, connection should be made when:

• Lamps are off

• . Voltage is low

• Frequency is mismatched

• Lamps shine at maximum brightness

In the dark lamp method, connection is done:

• After voltage drops

• When all lights blink

• Between last glow disappearance and next glow reappearance

• At full RPM