The value of 1 revolution of the meter disk, Expressed in watt hours.
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.
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.
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.
Register Constant or Multiplier
Multiplier of the register, due to gearing.
Transformer FactorMultiplier of the register, due to CT’s and/or CT X PT ratios.
A Potential-Flux and a Current-Flux, acting on a disk, in a time and space displacement.
A permanent magnet calibrated at the factory, with the known voltage and amperage to set the speed of the disk.
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.
A kilowatt-hour register, counting disk revolutions, displaying them in kilowatt-hours, accomplished at reduction at shaft
Industry standard to describe the meter
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)
Rated amperage a meter can continuously handle per phase, provided the meter housing and wiring are adequate
List the 6 parts of an Electro-Mechanical Meter
Base, Meter Disk, Kilowatt Hour Register, Permanent Magnet, Stator, Cover
List the 3 major meter types
List the 6 major parts of a Solid State meter.
CT's or Hall Effect Pickups
What are the 4 basic EM meter functions?
Drive, Drag, Lag, Record
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)
Primary Watt-hour Constant
The Watt-hour Constantx Transformer Factor
The average rate of consumption over a specific period of time
Define Calibrating Constant
The inverse of the number of current circuits in series under test.
(Establishes the Kh of individual elements)
An electrical load expressed in watts or kilowatts without a relationship to time. E x I=Watts
An electrical load expressed in watts or kilowatts times the number of hours it’s used.
E x I x time factor = Kwhr
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
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.
Test Amps Formula
E x I x CC x TF1,000 Rph for single phase500 Rph for Polyphase
Register Ratio Formula
10,000 x Kr TFxKhxRs
Kh x 3600 x revsTime in seconds
10,000 x Kr
TF X Rr x Rs
10,000 x KrTF x Kh x Rr
Rr x Rs
Kh x Rr x Rs x TF
Volts x Amperes (or) E x I
Volts x Amperes x Time (or) E x I x Time
E x I x CCx TF 1000
where “I” is equal to the amperage
on the meter under test
Draw a single phase delta bank and secondary lines
Draw and connect FM1/FM2/FM12 meters abase and socket
The industry wide standard to describe the meter construction and wiring.
Transformer Factor Formula
TF = 10,000 x Kr
Kh x Rr x Rs
CT ratio x PT ratio = TF
List the 4 basic Solid State meter functions
Sample: samples current & voltage at the CTs and meter stabs
Calculate: Multiplies current & voltage in phase to calculate watts being used
Converts data into a digital signal to be sent to the digital display
Displays consumption in Kwhrs or KW for billing purposes
Define Current Circuits (CC)
The number of current circuits in series under test
Define A-Base Meter
An electromechanical meter where the line and load side conductors are physically connected to the bottom of the meter
Define Socket Type Meter
A meter designed to plug into a pre-existing, pre-wired meter housing designed for the meter type and load.
With applied voltage only, the meter disk makes 1 full revolution either forwards or backwards in 10 minutes or less.
2 hots and a neutral connected to a wye system
A mechanical or solid state device used to prevent reverse rotation of the meter disk
Be able to use all formulas to solve equations.
What is a segment check?
Every pixel is lit up at once to test full functionality of the display
E=I x R
a2 + b2 = c2
Encoder, Receiver, Transmitter
Be able to explain a customers electrical use vs what the meter measures on a FM1 & FM2