Download 244-33LOADS

LOADS & VOLTAGE SYSTEMS
LOADS
DESCRIPTION
LIGHTING
DESCRIPTION:
MOTORS
A DEVICE THAT
CONSUMES
ELECTRICAL
ENERGY IN THE
PROCESS OF
PERFORMING
WORK.
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
DESCRIPTION
LIGHTING
LIGHTING:
MOTORS
PREDOMINANT
USER OF
ELECTRICAL
ENERGY IN MOST
BUILDINGS.
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
DESCRIPTION:
LOADS
DESCRIPTION
MACHINES WHICH
CONVERT
ELECTRICAL
ENERGY INTO
MECHANICAL
ENERGY.
LIGHTING
MOTORS
CONVENIENCE
OUTLETS
USUALLY THE
SECOND HIGHEST
USER OF
ELECTRICAL
ENERGY.
HEATING
ELEMENTS
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
REQUIRED TO
OPERATE FANS OR
PUMPS IN HVAC &
PLUMBING
SYSTEMS & ARE
ESSENTIAL
COMPONENTS OF
MOST INDUSTRIAL
PROCESSES.
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
HORSEPOWER
(HP):
DESCRIPTION
LIGHTING
MAXIMUM WORK
OUTPUT FROM THE
MOTOR SHAFT (1
HP = 746 WATTS).
MOTORS
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
FRACTIONAL
MOTORS: LESS
THAN ONE
HORSEPOWER.
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
INTEGRAL
MOTORS: ONE
HORSEPOWER &
ABOVE.
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
DIRECT CURRENT:
LOADS
USED PRIMARILY FOR
SMALL APPLICATIONS
AND WHEN CLOSE
CONTROL OF SPEED
OVER A WIDE RANGE
OF LOADS IS
ESSENTIAL.
DESCRIPTION
LIGHTING
MOTORS
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
ELECTRONIC
DEVICES
 ELEVATORS, CRANES,
& CERTAIN TYPES OF
FANS USE DIRECT
CURRENT
SPECIAL PROCESS
EQUIPMENT
HIGH OPERATING
EFFICIENCY.
RESISTIVE LOADS
& INDUCTIVE LOADS
REQUIRES ADDED
EQUIPMENT
(INVERTER) TO
CONVERT UTILITY A-C
POWER TO D-C,
MAKING D-C MOTOR
DRIVE MORE
EXPENSIVE.
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
SINGLE-PHASE
ALTERNATING
CURRENT:
DESCRIPTION
LIGHTING
MOTORS
LOWER SERVICE
ENTRANCE COST IF
ONLY A FEW SMALL
MOTORS ARE IN
SERVICE.
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
REQUIRES ONLY 2
HIGH-VOLTAGE LINES &
1 TRANSFORMER.
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
NOT AVAILABLE IN
SIZES ABOVE 7-1/2
HORSEPOWER.
RESISTIVE LOADS
& INDUCTIVE LOADS
TYPICALLY USED FOR
MOTORS ¾ HP & LESS.
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
THREE-PHASE
ALTERNATING
CURRENT:
DESCRIPTION
LIGHTING
MOTORS
CONVENIENCE
OUTLETS
DRAW LESS CURRENT
PER HP, THUS SMALLER
WIRE CAN BE USED.
HEATING
ELEMENTS
MORE RELIABLE.
ELECTRONIC
DEVICES
MORE EFFICIENT OVER
A WIDER RANGE OF
LOADING.
SPECIAL PROCESS
EQUIPMENT
REQUIRES THREE
HIGH-VOLTAGE LINES &
THREE TRANSFORMERS.
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
USED IN MOTORS 7-1/2
HP AND ABOVE.
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
DESCRIPTION
LIGHTING
UNIVERSAL
MOTORS:
MOTORS
CONVENIENCE
OUTLETS
RUN ON DIRECT
CURRENT OR
ALTERNATING.
HEATING
ELEMENTS
ELECTRONIC
DEVICES
APPLICATION:
MIXERS, HAND
DRILLS, ETC.
SPECIAL PROCESS
EQUIPMENT
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
DESCRIPTION
LIGHTING
MOTORS
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
ELECTRONIC
DEVICES
MOTOR EFFICIENCY:
SOME POWER IS WASTED AS HEAT IN THE PROCESS OF OVERCOMING
RESISTANCE IN THE WIRE & FRICTION IN MECHANICAL MOTION.
ENERGY EFFICIENCY RATIO (EER): RATIO OF OUTPUT TO WATTS-IN.
EER = SHAFT POWER (OUT)/ELECTRICAL POWER (IN)
EER = (HP X 746) / WATTS
THE LARGER THE RATING THE GREATER THE EFFICIENCY.
SPECIAL PROCESS
EQUIPMENT
TYPICAL RANGE: 85-95%.
RESISTIVE LOADS
& INDUCTIVE LOADS
EFFICIENCY OF SMALLER MOTORS IS LESS THAN LARGER MOTORS.
VOLTAGE
SYSTEMS
LIFE-CYCLE COST FAVORS HIGH EER.
LOADS
LOADS & VOLTAGE SYSTEMS
LIFE:
LOADS
PRIMARILY A
FUNCTION OF THE
HOURS OF
OPERATION.
DESCRIPTION
LIGHTING
MOTORS
SHORT-CYCLING
(DUTY CYCLING): STOP
& RESTART SERVICE
SHORTENS MOTOR
LIFE.
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
DUTY
CLASSIFICATION
UNDER-SIZE MOTORS
EASILY OVERHEAT &
BURNOUT.
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
RESISTIVE LOADS
& INDUCTIVE LOADS
OVERSIZED MOTORS
WASTE ENERGY BY
OPERATING AT LESS
THAN OPTIMUM
EFFICIENCY & MAY
WEAR OUT
PREMATURELY DUE
TO SHORT-CYCLING.
VOLTAGE
SYSTEMS
MOTOR NAMEPLATE
LOADS & VOLTAGE SYSTEMS
VOLTAGE:
LOADS
VOLTAGE RATING
REFERS TO THE
VOLTAGE OF THE
CIRCUIT TO WHICH
THE MOTOR SHOULD
BE CONNECTED.
DESCRIPTION
LIGHTING
MOTORS
CONVENIENCE
OUTLETS
TWO VOLTAGE
VALUES, SUCH AS
115/230 INDICATES
THAT THE MOTOR BE
CONNECTED TO
EITHER VOLTAGE.
HEATING
ELEMENTS
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
TYPICAL FOR
SINGLE-PHASE
MOTORS.
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
230-V MOTOR
CONSUMES ONLY ½ AS
MANY AMPS AS 115-V
ALLOWING LOWER
GAUGE WIRING.
MOTOR NAMEPLATE
LOADS & VOLTAGE SYSTEMS
LOADS
DESCRIPTION
LIGHTING
MOTORS
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
ELECTRONIC
DEVICES
SERVICE FACTOR:
INDICATES HOW MUCH OVER THE NAMEPLATE RATING A
MOTOR CAN BE DRIVEN WITHOUT OVER HEATING.
FRACTIONAL: 1.15-1.25.
LARGER MOTORS: 1.15
MOTORS OVER 200 HP HAVE NO SERVICE FACTOR.
SPECIAL PROCESS
EQUIPMENT
ALLOWS OCCASIONAL BUT PREDETERMINED OVERLOAD.
RESISTIVE LOADS
& INDUCTIVE LOADS
ALLOWS SLIGHT FUTURE EXPANSION.
VOLTAGE
SYSTEMS
COMPENSATES FOR OCCASIONAL EXCESSIVE AMBIENT
TEMPERATURE.
MOTOR NAMEPLATE
LOADS & VOLTAGE SYSTEMS
LOADS
CONVENIENCE
OUTLETS:
DESCRIPTION
LIGHTING
DEVICES INTO WHICH
PORTABLE ELECTRIC
APPLIANCES &
EQUIPMENT ARE
PLUGGED.
MOTORS
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
ELECTRONIC
DEVICES
RECEPTACLE CIRCUITS
ARE RATED ACCORDING
TO THE TOTAL
ANTICIPATED
AMPERAGE
REQUIREMENTS OF ALL
CONNECTED LOADS
OPERATING
CONCURRENTLY.
SPECIAL PROCESS
EQUIPMENT
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
HEATING ELEMENTS:
DESCRIPTION
LIGHTING
A LENGTH OF STAINLESS
STEEL WIRE FORMED INTO A
COIL & SUPPORTED ON
INSULATED PRONGS.
MOTORS
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
THE WIRE IS SIMPLY A
RESISTANCE TO THE
CURRENT & GENERATES
HEAT.
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
NORMALLY REQUIRES 240-V
IF LARGER THAN 1,500
WATTS/
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
DESCRIPTION
LIGHTING
MOTORS
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
DESCRIPTION
MOTORS
SPECIAL
EQUIPMENT:
CONVENIENCE
OUTLETS
X-RAY
EQUIPMENT.
LIGHTING
HEATING
ELEMENTS
LAB
EQUIPMENT.
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
LOADS
LOADS & VOLTAGE SYSTEMS
LOADS
DESCRIPTION
LIGHTING
MOTORS
CONVENIENCE
OUTLETS
HEATING
ELEMENTS
ELECTRONIC
DEVICES
SPECIAL PROCESS
EQUIPMENT
RESISTIVE LOADS
& INDUCTIVE LOADS
VOLTAGE
SYSTEMS
RESISTIVE LOADS:
CURRENT RISES QUICKLY TO ITS MAXIMUM VALUE
AT THE MOMENT THE LOAD IS ENERGIZED AND
STAYS THERE.
EG., NONBALLASTED LIGHTS & ELECTRIC HEATING
ELEMENTS.
INDUCTIVE LOADS:
DRAW A PEAK CURRENT QUICKLY & THEN DROP BACK TO A
VALUE 1/3 TO 1/5 OF THE PEAK VALUE.
EG., ELECTRIC MOTORS
LOADS
LOADS & VOLTAGE SYSTEMS
INTRODUCTION
LOADS
120-V, SINGLE-PHASE,
TWO WIRE
SECONDARY:
VOLTAGE
SYSTEMS
120-V, SINGLEPHASE, TWO WIRE
USED IN VERY SMALL
FACILITIES (SMALL
HOUSE OR OUTBUILDING).
120/240-V, SINGLEPHASE, THREE
WIRE
120/208-V, THREEPHASE, FOUR WIRE
ISOLATED SMALL
LOADS UP TO 6 KVA.
277/480-V, THREEPHASE, FOUR WIRE
120 X 50-AMPS = 6000
VA = 6 KVA.
2400/4160-V,
THREE-PHASE,
FOUR WIRE
VOLTAGE SYSTEMS
LOADS & VOLTAGE SYSTEMS
INTRODUCTION
120/240-V,
SINGLE-PHASE,
THREE WIRE
SECONDARY:
LOADS
VOLTAGE
SYSTEMS
REQUIRED IN
RESIDENCES WITH
SIX OR MORE 2 WIRE
CIRCUITS.
120-V, SINGLEPHASE, TWO WIRE
120/240-V, SINGLEPHASE, THREE
WIRE
SMALL STORES.
120/208-V, THREEPHASE, FOUR WIRE
OTHER
OCCUPANCIES
WHERE THE LOAD
DOES NOT EXCEED
80-A (80% OF 100-A
SERVICE).
277/480-V, THREEPHASE, FOUR WIRE
2400/4160-V,
THREE-PHASE,
FOUR WIRE
240 X 80-AMPS = 19.2
KVA.
VOLTAGE SYSTEMS
LOADS & VOLTAGE SYSTEMS
120-V/208, THREEPHASE, 4 WIRE
SECONDARY:
INTRODUCTION
LOADS
VOLTAGE
SYSTEMS
120-V LOADS
(LIGHTING, SMALL
MACHINES,
RECEPTACLES) FEED
BY CONNECTION
BETWEEN EACH PHASE
LEG & NEUTRAL.
120-V, SINGLEPHASE, TWO WIRE
120/240-V, SINGLEPHASE, THREE
WIRE
MOTORS LARGER
THAN ½ HP & ALL 3PHASE LOADS ARE
FEED AT 208-V BY
CONNECTION BETWEEN
THE 3-PHASE LEGS.
120/208-V, THREEPHASE, FOUR WIRE
277/480-V, THREEPHASE, FOUR WIRE
2400/4160-V,
THREE-PHASE,
FOUR WIRE
SINGLE-PHASE, 208-V
LOADS FEED BY
CONNECTION BETWEEN
TWO PHASE LEGS.
VOLTAGE SYSTEMS
LOADS & VOLTAGE SYSTEMS
INTRODUCTION
LOADS
VOLTAGE
SYSTEMS
120-V, SINGLEPHASE, TWO WIRE
120/240-V, SINGLEPHASE, THREE
WIRE
120/208-V, THREEPHASE, FOUR WIRE
277/480-V, THREEPHASE, FOUR WIRE
120/208-V, THREEPHASE, FOUR WIRE
SECONDARY:
MOST WIDELY USED 3PHASE ARRANGEMENT
& IS APPLICABLE TO
ALL FACILITIES EXCEPT
THE VERY LARGEST
ONES (LONG FEEDERS
REQUIRE HIGHER
VOLTAGE).
2400/4160-V,
THREE-PHASE,
FOUR WIRE
VOLTAGE SYSTEMS
LOADS & VOLTAGE SYSTEMS
277-V/480,
THREE-PHASE, 4
WIRE
SECONDARY:
INTRODUCTION
LOADS
VOLTAGE
SYSTEMS
UTILIZES 277-V FOR
FLUORESCENT
LIGHTING.
120-V, SINGLEPHASE, TWO WIRE
480-V FOR
MACHINERY.
120/240-V, SINGLEPHASE, THREE
WIRE
ELECTRICAL CLOSET
WITH STEP-DOWN
TRANSFORMER FOR
SUPPLYING 120-V
LOADS.
120/208-V, THREEPHASE, FOUR WIRE
277/480-V, THREEPHASE, FOUR WIRE
USED IN LARGE
BUILDINGS WHERE
LIGHTING IS
PRINCIPALLY
FLUORESCENT & THE
120-V LOAD DOES NOT
EXCEED 1/3 OF THE
TOTAL LOAD.
2400/4160-V,
THREE-PHASE,
FOUR WIRE
VOLTAGE SYSTEMS
LOADS & VOLTAGE SYSTEMS
INTRODUCTION
LOADS
VOLTAGE
SYSTEMS
120-V, SINGLEPHASE, TWO WIRE
120/240-V, SINGLEPHASE, THREE
WIRE
120/208-V, THREEPHASE, FOUR WIRE
2400-V/4160, THREE-PHASE, 4 WIRE
SECONDARY:
USED ONLY IN VERY LARGE COMMERCIAL
BUILDINGS OR IN INDUSTRIAL BUILDINGS
WITH MACHINERY REQUIRING THESE
VOLTAGES.
277/480-V, THREEPHASE, FOUR WIRE
2400/4160-V,
THREE-PHASE,
FOUR WIRE
VOLTAGE SYSTEMS