1st Step Written (2016)

• Watt hour constant
• The value of 1 revolution of the meter disk, Expressed in watt hours.

• Register Ratio
• The number of turns of the 1^st gear of the register to cause the 1^st (or right hand) dial pointer to complete 1 full revolution which = 10,000 watt hours or 10kwhrs.

• Gear Ratio
• The number of turns of the meter disk to cause the 1^st (or right hand) dial pointer to complete 1 full revolution = 10,000 watt hrs or 10kwhrs.

• Reduction at Shaft
• The ratio between the number of teeth on the 1^st 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 Factor
• Multiplier 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

Rated amperage a meter can handle continuously per phase, provided the meter housing and wiring are adequate

Base, Meter Disk, Kilowatt Hour Register, Permanent Magnet, Stator, Cover

• A Base-electromechanical
• Socket-electromechanical
• Socket-Solid state

• Base
• Cover
• Digital Display
• CT's or Hall Effect Pickups
• Circuit Board
• Current Coils

Drive, Drag, Lag, Record

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 Constant x Transformer Factor

The average rate of consumption over a specific period of time

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

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.

• E x I x CC x TF
• 1,000 Rph for single phase
• 500 Rph for Polyphase

• 10,000 x K_r
• TFxK_hxR_s

• K_h x 3600 x revs
• Time in seconds

• 10,000 x Kr
• TF X Rr x Rs

• 10,000 x Kr
• TF x Kh x Rr

Rr x Rs

• Kh x Rr x Rs x TF
•        10,000

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

• TF =  10,000 x Kr
•         Kh x Rr x Rs
• (or)

CT ratio x PT ratio = TF

• Sample
• Calculate
• Convert
• Display

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

The number of current circuits in series under test

An electromechanical meter where the line and load side conductors are physically connected to the bottom of the 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.

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

Every pixel is lit up at once to test full functionality of the display

E=I x R

a² + b² = c²

Encoder, Receiver, Transmitter