Electrical Estimating Techniques

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Octet Rule: Definition, Explanation, Exceptions and Examples

Nov 19, 2019The octet rule is one of the chemical "rules of thumb" stating that atoms prefer to combine in a manner such that each atom has 8 electrons in their valence shells. A valence shell is the outer shell of an atom. Eight electrons in the outer shell allows atoms to have a configuration that is similar to the closest noble gas.

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Fire Protection and Prevention

some plastics, wood and cloth. A rule of thumb is if it leaves an ash behind, it is a Class A fire. Class B—fires involving flammable gases or liquids, such as propane, oil and gasoline Class C—fires involving energized electrical components Class D—fires involving metal. A rule of thumb is if the name of the metal

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Overcurrent protection

May 02, 2015Rules of Thumb( above 600 V) Power Transformers Secondary Solidly Grounded Secondary Solidly Grounded (for balanced three phase industrial loads) •If secondary is solidly grounded and neutral relay is available (using CT on X0 bushing) set pickup at approximately 50% of phase element and ensureX0 bushing), set pickup at approximately

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Estimation of water requirement for drinking and domestic

Central Ground Water Authority, Government of India 2 Water Requirements for Buildings Other than Residences Sl No. Type of Building Domestic litres per head/ day Flushing Litres per head/ day Total Consumption Litres per head/ day 1. Factories including canteen where bath rooms are required to be provided 30 15 45

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High Voltage Capacitors and Power Resistors

A practical rule-of-thumb for choosing the correct part size and the amount of capacitance for a DC motor with an operating voltage of 12 -24 volts is to start with a 50 volt 1410 EMI component with approximately 400 nf of capacitance. ensure that metal bearings or bushings are properly grounded to the housing (Figure 12). When shunting

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BASIC NEC CODE RULES AND DESIGN PRACTICE

Rule of Thumb If circuit is loaded up to ampacity and distance to load is around 100 feet, then voltage drop will govern and will require larger wire size. If more than 3 phase wires are in one conduit, then wires must be derated according to Note 8, after Table 310-19 as follows: TABLE 1 Number of Conductors Percent of Values in 310-16

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Power Frequency Withstand Testing of 38kV Switchgear

The equipment can be separated into smaller sections to reduce the charging current requirements of the bushings. Restricting the number of bushings in the test circuit to draw about 75% of the test equipment output is a reasonable rule of thumb to avoid false tripping due to the charging current on the bushings.

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Tips, techniques for nonperpendicular holemaking

Dec 28, 2016Each sub was loaded into a jig that held it at the required angle, and a metal plate fitted with hardened steel bushings was then clamped to the top of the jig before the holes were produced with a drill press. Holemaking up to 20 from perpendicular is the rule of thumb for most annular-cutting operations. Image courtesy Hougen Manufacturing.

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General

Nov 29, 2021All that is required for the coil to fire is for the ground lug of the coil to find a path to ground. This is accomplished by turning on a transistor, or by closing a switch that creates a path to ground. Flipper bushing binding. the Rule of Thumb is 3 1/2 degrees for EM games and 6 1/2 to 7 degrees for solid state games. Use an

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Simple Rules for Rounding Numbers Correctly

Sep 01, 2019One rule of thumb is to round to $50 and leave a 15 percent tip. To quickly figure out the tip, say that $5 is 10 percent, and to reach 15 percent you need to add half of that, which is $2.50, bringing the tip to $7.50. If you want to round up again, leave $8—if the service was good, that is. Featured Video.

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Elevation Changes and How They Affect Engine Tuning

Dec 22, 2017A good rule of thumb is to decrease the barometer value by 1 inHg for every 1,000 feet of altitude increase. This means that a barometer value of 29.54 inHg at sea level would be approximately 28.54 inHg at 1,000 feet of elevation. In Colorado, with an approximate elevation of 5,000 feet, the uncorrected value is around 24.54 inHg.

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Talking Durometer—Bushing 101 with Energy Suspension

Generally a single durometer is offered for a single application—there aren't "soft," "medium," and "hard" bushings available for your stock control arms and the general rule of thumb is said to be that polyurethane bushings last about 10 times longer than the rubber bushing they replace, which means that in all but the most

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Overcurrent Protection Coordination forOvercurrent

Rules of Thumb(above 600 V) PTfPower Transformers Primary Ground Relay Settings Primary – Ground Settings •Set 50G if primary winding is delta connectedSet 50G if primary winding is delta connected. •Provide time delay (approx 20 msec) when setting digital relays with zero sequence CTs. No time delay when using elecro-mechanical relays with

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How To Pass Safety Inspection

Nov 14, 2016With the front end of the car jacked up off the ground, grab each front wheel at the 3 o'clock and 9 o'clock positions and push it back and forth alternately on each side. You're feeling for play

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Insulation Resistance Test (IR Test) or Megger Test

Aug 16, 2014Insulation Resistance or IR Test is carried out by maintenance engineers to ensure the healthiness of the overall insulation system of electrical equipment.. It reflects the presence or absence of harmful contamination, dirt, moisture, and gross degradation. IR value will be usually high (several hundred Megaohms) for a dry insulation system.

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Which Size Box?

Considering an angle pull, if the enter and exit walls contain raceways of 3, 2 and 1 in. respectively, multiply 3 inches by 6, and add 2 inches and 1 inch. That equals 21 inches. Therefore, the size box for an angle pull is 21 inches by 21 inches. As another rule of thumb to size a box for an angle pull, multiply the largest of the raceways by 10.

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Can you split a butterfly bush?

Jan 30, 20204.8/5 (1,310 Views . 39 Votes) Butterfly bush can also be propagated through division of its roots. This can be done in spring or fall, depending on where you live and personal preference. Carefully dig up mature butterfly bushes and remove excess soil. Then either separate the roots by hand or use a spade shovel to divide the plants.

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Bonding

Ground Straps. The first rule to follow about ground straps, is to keep them short! The rule of thumb is, 10 inches or less! And, there is a reason for why. A ground strap, like any piece of wire, has both inductive and capacitive reactances, which change with frequency.

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Understanding Insulation Resistance Testing

When AC voltage is used, the rule of thumb is 2 x nameplate voltage + 1000. When DC voltage is used (most common on megohmmeters manufactured today) the rule of thumb is simply 2 x nameplate voltage except when higher voltages are used. See chart below for suggested values. Equipment/Cable Rating DC Test Voltage 24 to 50V 50 to 100VDC

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CAPSTAN HOIST

is a rule of thumb that may be used for friction, so 800 lb. plus 80 lb. (10%) equals 880 lb. The same is true for a gin or sling used to support the block. NEVER USE A MALFUNCTIONING OR DAMAGED HOIST! BEWARE OF POTENTIAL DANGER ZONES AND STAY CLEAR.

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How to Ground A Generator Correctly

Jul 28, 2019In hard ground, some water to soften the ground will make this easier. If the ground is rocky, you may have to drive the rod in at an angle. This angle may not exceed 45. Driving an 8' rod into the ground at an angle of 45 will mean that it will reach the required 4', if the entire length of the rod is driven into the ground.

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Plant Engineering

Jun 25, 2001As a rule-of-thumb, this thickness should be the same as the distance from the base to the center height of the housing being supported. Spacer couplings should always be used on fans and blowers. If a spacer coupling is not used, the motor must be pulled off its base when a bearing replacement is required, which requires extra time.

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Failure Analysis for Plain Bearings

Failure Analysis for Plain Bearings. William Strecker, Kingsbury. The textbook cases of distress modes are especially useful in diagnosing problems prior to the damage that occurs when a bearing can no longer support an oil film. Through the prudent use of temperature and vibration monitoring equipment, routine oil analysis, lubrication system

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The 10 Most Common National Electric Code Violations

Dec 29, 2020Ground Fault Circuit Interrupter. Ground fault circuit interrupters (GFCIs) protect people in areas where they are likely to be using small appliances and where water is present. GFCI breakers and outlets have been around for awhile, and most people know they're required in bathrooms, kitchens and outdoors.

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Technical Articles

Dec 06, 2021Premium Membership Required This technical article/guide requires a Premium Membership. You can choose an annually based Plus, Pro, or Enterprise membership plan. Subscribe and enjoy studying specialized technical articles, online video courses, electrical engineering guides, and papers.

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Standardizing The Measurement Process To Find The Right

Mar 17, 2014This assumption is true, to a point: there are rules of thumb that can be used to convert Ra to Rz or Rz to Ra. Using a ratio range for Rz to Ra between 4-to-1 and 7-to-1 is a safe conversion. However, if the manufacturer uses Ra but the customer uses Rz, then the conversion ratio would be much higher, possibly as high as 20-to-1.

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Minimizing Noise by Switched

May 25, 2016It is associated with the parasitic inductances in the current path. It includes parasitic inductances resulting from the printed circuit board (PCB) traces, IC package leads, and multilayer PCB vias, and die-bonding wires. As a rule of thumb, Dostal says, an inch of PCB trace has about 20 nH of parasitic inductance.

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How to estimate the quantity of rebar in slab

Answer (1 of 8): Method 1: You can make a rough estimate by using thumb rule that about 80 kg of rebar is required per cum. of slab. So if slab size is say 10m x 10m x 0.2m. Concrete = 10 x 10 x 0.2 = 20 cum. Therefore, Rebar = 80 kg x 20 = 1600 kg =

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Basic rules for design of beams

Feb 22, 2020Simplified Curtailment Rules for Tension Reinforcement in Beams (As Per SP 34) The curtailment of tension reinforcement in beams is related to the bending moment diagram and rules given above. However, simplified curtailment rules are given in SP 34 (handbook on concrete reinforcement and detailing) and are given in Figs. 6.4 and Fig. 6.5.

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1203AA 64

easier to get at the Can bushings for removal and replacement. The only problem with this method is that it requires much more to be disconnected e.g. brake lines, parking brake, axle u-joint, and lower trailing arms. However, it is possible to remove the Can Bushings without taking the rear end off the car, but it's tricky.

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4.401/4.464 Environmental Technologies in Buildings

Window-Head-Height Rule of Thumb. In a sidelit space with a standard window and venetian blinds, the depth of the daylit area usually lies between 1.5 and 2 timesthe window-head-height. If a space does not require the use of a shading device

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XFMR III Test Flashcards

XFMR III Test. T/F: A dust buildup on the surface of a transformer can create a conductive path between taps and bushings. The dissolved moisture in transformer insulating oil should be below about ? parts per million (ppm).

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Code Requirements on Aboveground Storage Tanks

entry. When required, provide protection against vehicular collision by suitable barriers, such as 4" diameter steel pipe filled with concrete set 3' deep in a concrete footing and spaced no more than 4' apart. International Fire Code, 2000 Edition Impact protection required by system design, barriers or posts.

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CURRENT TRANSFORMER SATURATION – Voltage Disturbance

Aug 14, 2018A popular rule of thumb is to have C rating twice the excitation voltage developed during maximum fault current. Standard burden for relaying are 1, 2, 4 and 8 Ω with a power factor of 0.5. ANSI accuracy class only applies to the full winding of the CT .

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High Voltage Spacing

In addition, there are requirements from UL, IEC, and IPC to consider when designing products. Spacing Concerns When evaluating spacing, both clearance and creepage distances need to be addressed. Clearance is the shortest distance between two conductive parts, or between a conductive part and ground, measured through air or other insulating

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Rules of Thumb for Thread Engagement

Mar 13, 2018Percent of thread engagement is based size of the mating hole compared to the fastener and how much the height of threads of the screw are engaged. For example a #10-24 thread forming screw will have around 80% thread engagement in a .1683" hole, while around 70% thread engagement in a .1710" hole.

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All about Skateboards Bushings

Bushings are a very important part of skateboard trucks. Every truck is equipped with two bushings – the street-facing top bushing, and the board-facing bottom bushing. Like skateboard wheels, bushings are made of polyurethane, i.e. plastic. Bushings are available in many different colours, shapes, and degrees of hardness.

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The 10 Ground Rules for Meetings

Jul 17, 2017This is where meeting ground rules come in to play. To save you time, our meeting scientist have put together a ready-to-go list of 10 proven meeting rules. Download the Meeting Rules to share with your meeting participants, or just print and post them in

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Press fit on plastic

Mar 04, 2020Delrin will stand quite a bit of interferance and is pretty stable,how much is really depended on the size and geometry. Nylon is probably the worst,the crap changes as it ages.I made some 8 nyloil with moly sulfide wheels with an approximatly 2.5 bearing with a .010 interferance fit and within a week the bearings fell out.I ended up using tolerance rings and

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