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Semi final
4th year
| Question | Answer |
|---|---|
| Class one copper lightning protection terminals have a min.diameter of | 3/8 inch |
| Class 2 copper air terminal | 1/2 inch |
| Class 1 aluminum air tetminal | 1/2 inch |
| Class 2 aluminum air terminal | 5/8 inch |
| Class 1 | 75' or lower smaller than class 2 |
| Class 2 | 75' larger and heavier |
| Ground Rods min. Depth | 10 ft. |
| What needs to be at least 10 inches above the object of area its protecting of lightning strikes | The tip of the air terminal |
| For lightning protection systems all structures require at least 2 down conductors and at least one additional down conductor | For every 100 ft. Of roof perimeter over 250 ft. |
| NFPA _______ is the standard for the installation of lightning protection systems | 780 |
| 4 main parts of lightning protection systems | 1.intercept 2.strike termination devices3.termunal4.lightning rods |
| 2nd part lightning strikes down the building.includs the bonding of metallic bodies to a LPS conductors in an attempt to keep all metallic components at ___________during lightning strike event | Equal potential |
| 3rd part | Disperses lightning strike safety to earth materials,ground rods electrodes,ground rings,radials |
| 4th part | Surge suppression devices to dispose of ant unwanted electrical currents attempting to enter the building through conductive wiring |
| Bimetallic can't be used within______ of earths surface | 18 inches |
| Ground ring electrode | Conductor encircles a structure that is in direct contact with earth |
| If you have pride you also have to have | Effort and dedication |
| Labelled | It means there is some sort of symbol or identifying mark from an organization that is acceptable to AHJ |
| Listed | When it is on a list published by an organization |
| Loop conductor | A conductor that encircles a structure that interconnecs ground electrodes |
| Depth of topsoil before encasement in concrete | Less than 18 inches |
| How many feet between supports of cables | 3ft. |
| Air terminals that extend 24 inches above an object are permitted to be in place of intervals not exceeding ______ | 25 ft. |
| Lightning protection in a basement and crawl space? | Close as possible to outer perimetet |
| Bonding conductor | A conductor used for potential equalization between grounded metal bodies and a LPS |
| The surge protection devices installed at a service entrance have a min rating of 40 ka and a nominal discharge of | 20 ka |
| Main conductor | A conductor that carries lightning currents between strike terminations devices and grounding electrodes |
| What is not found on a motor plate | VA |
| The output of an alternator is controlled by a stator or rotor wire length strength of magnetic field | Speed of motor RPM,speed of generator |
| Magnetic flux is densist and magnetic force is strongest | At the poles north pole to south pole |
| Change the direction of DC motor | Commutator |
| Change the direction of ac motor | Switch the legs |
| Trouble shooting motors use a | Digital multi meter |
| What is connected to the rotor of a wound rotor motor specifically the set of secondary resistor | Slip rings |
| 1 HP = | 746 watts |
| The actual voltage applied to s motor should be within plus or minus_____ of the motors nameplate voltage | 10% |
| Motor power is rated in | Horsepower/watts |
| Motor A | Normal starting torque and normal starting current |
| Motor B | Normal starting torque low starting current *most common |
| Motor C | Has a high starting torque and low starting current |
| Motor D | High starting torque high slip and low starting current |
| A _______ DC motor has the highest starting torque characteristic | Series |
| In a 2 pole single phase motor the start winding is placed ____ from the run winding | 90 degrees |
| In a capacitor start motor forward and reverse I'd controlled by a | Drum switch |
| The _______ of a squirrel cage induction motor are short ckt | Rotor windings |
| The ______ of a wound rotor motor ate not short ckt | Rotor windings |
| The _______is used in a DC generator to keep the polarity and output in one direction | Commutator |
| Overload relay | Time delay devices that allow temporary overloads without disconnecting the motor |
| Primary colors | Blue green red |
| Secondary colors | Cyan magenta yellow |
| How do u measure lighting | Footcandles |
| What lighting is adjustable | A symmetrical |
| The visual task occurs at the ______ in the kitchen | Counter level |
| Lumen maintenance | Describes how long a light source will retain its own lumen output |
| What is SAD | Seasonal affective disorder |
| SAD and circadian are known as what type of issue | Photo biological disorfet |
| Argon and crypton | Combined with vaporized mercury produce visible light with phosphor |
| Chief disadvantage to use his and electromagnetic ballast lifting systems is | Lumen maintenance |
| Configurable relay | Relay designed to accept additional sets of contacts called add ons |
| Machine control relay | Electromagnetic relay that consists of several contacts typically 2-8 up to 12 |
| Interposing relay | A really that enables the energy in a high power ckt to be switched by a low power control signal |
| Recommended d.b. for hazardous situation | 25 above ambient sound |
| What % of the world used motors | 63% |
| Type of enclosures | Type 1 I door,2 outdoor,3 both 4 submerged |
| Size holes iec | 16 or 22.5 smaller |
| Nema | 30.5 larger |
Created by:
busybee1117