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Define Kh
- Watt hour constant
- The value of 1 revolution of the meter disk, Expressed in watt hours.
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Define Rr
- Register RatioThe number of turns of the 1st gear of the register to cause the 1st (or right hand) dial pointer to complete 1 full revolution which = 10,000 watt hours or 10kwhrs.
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Define Rg
- Gear RatioThe number of turns of the meter disk to cause the 1st (or right hand) dial pointer to complete 1 full revolution = 10,000 watt hrs or 10kwhrs.
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Define Rs
- Reduction at ShaftThe ratio between the number of teeth on the 1st gear of the register to the number of entries on the disk shaft.
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Define Kr
- Register Constant or Multiplier
Multiplier of the register, due to gearing.
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Define TF
- Transformer FactorMultiplier of the register, due to CT’s and/or CT X PT ratios.
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Define Drive
A Potential-Flux and a Current-Flux, acting on a disk, in a time and space displacement.
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Define Drag
A permanent magnet calibrated at the factory, with the known voltage and amperage to set the speed of the disk.
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Define Lag
Potential-Flux must lag Current-Flux by exactly 90 electrical degrees at unity power factor to establish max torque of the disk at any given load power factor.
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Define Record
A kilowatt-hour register, counting disk revolutions, displaying them in kilowatt-hours, accomplished at reduction at shaft
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Define Form
Industry standard to describe the meter
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Define Class
Rated amperage a meter can handle continuously per phase, provided the meter housing and wiring are adequate
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List the 6 parts of an Electro-Mechanical Meter
Base, Meter Disk, Kilowatt Hour Register, Permanent Magnet, Stator, Cover
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List the 3 major meter types
- A Base-electromechanical
- Socket-electromechanical
- Socket-Solid state
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List the 6 major parts of a Solid State meter.
- Base
- Cover
- Digital Display
- CT's or Hall Effect Pickups
- Circuit Board
- Current Coils
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What are the 4 basic EM meter functions?
Drive, Drag, Lag, Record
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Define Test Amps
Amperage used with line voltage to set the speed of the disk in 1 hour’s time. (1000Rph 1phase) (500Rph Poly phase)
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Define PKh
Primary Watt-hour Constant
The Watt-hour Constant x Transformer Factor
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Define Demand
The average rate of consumption over a specific period of time
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Define Calibrating Constant
The inverse of the number of current circuits in series under test.
(Establishes the Kh of individual elements)
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Define Power
An electrical load expressed in watts or kilowatts without a relationship to time. E x I=Watts
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Define Energy
An electrical load expressed in watts or kilowatts times the number of hours it’s used.
E x I x time factor = Kwhr
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Define Stator (Meter Element)
The unit that provides the driving torque in a watt-hour meter. It includes the Potential-Coil, the Current-Coil and the related framework to provide a magnetic flux or path
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Blondel's Theorum
In a system of N-conductors, N-1 metering elements properly connected, will measure power and/or energy consumed, provided that all potential coil(s) have a common connection in which no current circuit(s) are connected.
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Test Amps Formula
- E x I x CC x TF1,000 Rph for single phase500 Rph for Polyphase
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Watts Formula
- Kh x 3600 x revsTime in seconds
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Power Formula
Volts x Amperes (or) E x I
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Energy Formula
Volts x Amperes x Time (or) E x I x Time
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Demand Formula
- E x I x CCx TF 1000
- where “I” is equal to the amperage
- on the meter under test
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Draw a single phase delta bank and secondary lines
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Draw and connect FM1/FM2/FM12 meters abase and socket
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Transformer Factor Formula
- TF = 10,000 x Kr
- Kh x Rr x Rs
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CT ratio x PT ratio = TF
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List the 4 basic Solid State meter functions
- Sample
- Calculate
- Convert
- Display
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Define Sample
Sample: samples current & voltage at the CTs and meter stabs
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Define Calculate
Calculate: Multiplies current & voltage in phase to calculate watts being used
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Define Convert
Converts data into a digital signal to be sent to the digital display
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Define Display
Displays consumption in Kwhrs or KW for billing purposes
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Define Current Circuits (CC)
The number of current circuits in series under test
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Define A-Base Meter
An electromechanical meter where the line and load side conductors are physically connected to the bottom of the meter
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Define Socket Type Meter
A Socket meter is an electromechanical meter in which the meter is designed to plug into a pre-existing meter socket / housing where all the line and load conductors are wired to the internal socket.
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Define Creep
With applied voltage only, the meter disk makes 1 full revolution either forwards or backwards in 10 minutes or less.
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Network System
2 hots and a neutral connected to a wye system
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Define Detent
A mechanical or solid state device used to prevent reverse rotation of the meter disk
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Be able to use all formulas to solve equations.
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What is a segment check?
Every pixel is lit up at once to test full functionality of the display
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Pythagorean's Theorem
a2 + b2 = c2
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Define ERT
Encoder, Receiver, Transmitter
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Be able to explain a customers electrical use vs what the meter measures on a FM1 & FM2
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