Mechanical & electrical systems
moore05
DiscussionResponse.docx
DG
What is a service entrance and why are their specific code requirements for these about location and other parameters associated with this element of the design?
A service entrance is the link between the power company and a residence. Service entrances provide all the equipment needed to provide electricity and distribute it to the residence.
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How is equipment protected from transients?
Protection methods against transients include proper wiring, grounding, shielding of the power lines and use of surge suppressors. Transient is a temporary, unwanted voltage in an electrical circuit. A surge suppressor is a receptacle that provides protection from high-level transients by limiting the level of voltage allowed downstream from the surge suppressor that is installed at the service entrance panels and individual loads.
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When does a transformer become overloaded?
A transformer is overloaded when it is required to deliver more power than its rating. The power rating of a transformer indicates the amount of power the transformer can safely deliver.
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I D
Discuss the different types of power loss that occur in transformers.
Eddy current loss is caused by the induced currents that are produced in metal parts that are being magnetized. In a transformer, eddy current loss occurs in the iron core because the iron core is magnetized.
Copper loss is caused by the resistance of the copper wire to the flow of current. The higher the resistance, the greater the loss.
Hysteresis loss is caused by magnetism that remains in a material after the magnetizing force has been removed. Hysteresis loss occurs every half cycle of AC when the current reverses direction and some magnetism remains in the iron core.
Hysteresis loss, eddy current loss, and copper loss all produce losses in the transformer due to the heat they develop in the metal parts.
Respond
What is a service entrance and why are their specific code requirements for these about location and other parameters associated with this element of the design?
Service entrances are the link between a building and the power company. Service entrances provide all the equipment necessary to obtain electricity and distribute it throughout a residence. Cost and convenience are both factors when determining the placement of a service entrance. Electricians must try to make the service panel of the residence as accessible as possible using the minimum of materials.
Respond
How is equipment protected from transients?
Protection methods commonly include proper wiring, grounding, shielding of power lines, and use of surge suppressors.
Respond
J H
When does a transformer become overloaded?
A transformer becomes overloaded when it is required to deliver more power than its rating.
Respond
Discuss the different types of power loss that occur in transformers.
Hysteresis loss is caused by magnetism that remains in a material after the magnetizing force has been removed. This occurs every half cycle in an alternating current when the current reverses direction.
Eddy-current loss is caused by induced currents produced in metal parts being magnetized.
Copper loss is caused by the resistance of copper wire to the flow of the current.
Respond
What is a service entrance and why are their specific code requirements for these about location and other parameters associated with this element of the design?
A service entrance in the link between a residence and power company. The specific code requirements about the location is for cost and convenience. Cost is determined by using a minimum amount of materials and convenience being the maintenance and install that may be required.
