GE MS6001B, Maintenance Instructions Manual

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Inspection and Maintenance Procedures Inspection and Maintenance
IMP–22
This arc is extinguished when the contacts are fully open. However, it may be established and extin-
guished several times due to contact bounce. The arc may be a glow discharge, or even a small metal-
lic bridge, which becomes hot enough to vaporize a small portion of the contact metal. Repeated
arcing causes erosion, pitting, and general deterioration, and results in high contact resistance.
Where arcing is a problem, two or more contacts can be connected in series. The voltage induced
across each contact is reduced accordingly. This in turn, reduces or entirely eliminates arcing. Other
solutions are:
1. Connect a capacitor and resistor across the contacts.
2. Connect a diode across the contact load.
BATTERY SYSTEM
**WARNING**
Batteries give off hazardous fumes during normal op-
eration. Do not smoke, use open lights or allow open
flames near batteries. Exercise extreme care if using
metallic tools or other equipment which could short
out battery terminals. Sparking or arcing could result
in an explosion. Electrolyte is an acid and can cause
severe burns. Always wear protective clothing such as
a rubber apron, safety goggles and rubber gloves when
performing any maintenance or inspections on
batteries.
Battery
Refer to battery manufacturer’s recommendations in the Power Auxiliaries Support System Tab in Vol-
ume II.
Battery Charger (if applicable)
Refer to battery manufacturer’s recommendations in the Power Auxiliaries Support System Tab in Vol-
ume II.
MOTOR CONTROL CENTER
Circuit Breakers
Check the circuit breakers for physical damage to the switching unit. Check the switching unit for accu-
mulation of dust, dirt and the security of all connections.