Term
| What are the purposes of inert gas fillers in fuses? |
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Definition
- Quench the arc
- Increase voltage rating
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Term
| What are the requirements of OP-LG-102-1002, specific to blown fuses? |
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Definition
- Shift management must be notified to approve replacement/resetting protective devices
- If fuse blows a second time, replacement should not be allowed without further investigation
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Term
| What inspections are performed on a fuse, prior to replacement? |
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Definition
- Coninuity test,
- End caps not loose,
- Overall condition,
- Fuse block clip not corroded
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Term
| Fuse selection requirements (3) |
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Definition
- Must carry normal load,
- Must interrupt the overcurrent and withstand voltage across fuse during arcing (after it opens)
- Must coordinate with other protective devices (only nearest fuse should open)
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Term
| Why shouldn't you use a fuse that is missing a label? |
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Definition
| It could have been exposed to moisture. |
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Term
| How do you test if a fuse is blown (in a 3 phase circuit)? |
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Definition
| Using a voltmeter, measure voltage across any two phases. If there is a difference the fuse is blown. |
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Term
Which multi-meter mode of operation can cause a low resistance path in the circuit being tested?
Why is this bad? |
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Definition
Resistance-measuring mode
Can cause a signal to be generated in the circuit. |
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Term
| Why must caution be exercised when installing fuses in an energized circuit? |
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Definition
| Arcing may occur, causing severe burns. |
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Term
Provide the number of valence electrons for:
- Conductors
- Semi-conductors
- Insulators
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Definition
- 1 or 2, Conductors
- Between 3 and 6, Semi-conductors
- 6 or 7, Insulators
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Term
| Name the three elements necessary to have an electrical circuit. |
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Definition
- Power source
- Load
- Conductor or wire
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Term
| What is the function of a fuse? |
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Definition
| To break a circuit, should it become overloaded. |
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