Exam 8: Overload Units

Overload units are designed with an inverse time-delay function.

The absolute best way to assure adequate motor protection is to consult the cover of the motor ____, the motor control center, or the manufacturers catalog at the time of installation.

The eutectic alloy in the heater barrel element is a material that goes from a solid state to a liquid state without going through an intermediate ____ stage.

Overload protection is designed with inverse time-delay trip characteristics.This means the ____ the overload current the faster the circuit will open, but a smaller overload would take much longer to open the circuit.

Overload units utilize the motor load current to mimic the _______________ characteristics of the motor being protected.

Overload units are designed to help energize a motor that is building up excessive heat.

Electronic type of thermal overload units are adjustable for a range of motor load currents, and are set for the full load amperes (FLA) of the specific motor load.

The most common type of overload unit is the electronic overload unit.

What is the best way to assure adequate protection for an overload unit?

When the melting alloy is a solid, the shaft of the ratchet wheel is held from turning.

Electronic motor overload units ____ the motor differently than either the melting alloy or the bimetallic overload units.

What are the three most common types of overload units?

The overload unit contacts are connected in parallel with the motor starter contactor unit control coil.

When the bimetallic strip is heated, the metal with the lower thermal expansion characteristic will become longer, and cause the metal strip to bend.

It is important to understand that each different type of overload protection method requires its own _______________.

Thermal overload units conduct the motor load current through heater elements.

The thermal overload unit of the motor starter is located below the ____ contractor.

A bimetallic strip is used as a(n) _______________ lever.

The _______________ unit is operated by heat developed from the motor load current going through the overload heaters.

The three most common types of overload units are the melting alloy (eutectic), bimetallic, and _______________.