what is a drive

8/3/2019 what is a Drive

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TEAMWORK & TECHNOLOGY

Drive Basics

WHAT IS A DRIVE


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Drive Basics

RPM =

120 x Applied Frequency

Number of Poles per Phase

SYNCHRONOUS SPEED

e.g for a 4 POLE & 50 Hz FREQUENCY

RPM = 120 X 50 = 1500

4


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Drive Basics

SLIP

Speed Speed

0 750 1440Base

1500Sync

60 RPM

Slip

N

Rotor Speed = Synchronous Speed - Slip Speed


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Drive Basics

AC MOTOR REVIEW

T = K x x ILine

E

F

2

In an AC motor, torque varies by:

where : E/F proportional to Motot Flux

I is current drawn by the motor

PLAY WITH V/F RATIO TO GET HIGHER STARTING TORQUE


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Drive Basics

CAUTION1.Wide Speed Range will not eliminate Gear Reducer

HP =

Torque x Speed

5252

Wide Speed Range reduces pulsating torque

2. Define Customers speed range down to machine end

Drive2.5 Hz-50 Hz

75-1500 RPM

1:20 Machine

3.25 - 75 RPM


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Drive Basics

Mechanical

Constant Speed

Motor

ACMotor

Variable

Speed

Shaft

Vary Pitch Diameter

Eddy current

ConstantSpeed Motor

AC

Motor

Exciter

Coupling Field

Solid state DC

DCMotor

DC OutputACInput

Rotating DC

Field Control

DCMotor

ACMotor

DCGen

Solid state AC

ACMotor

Fixed DC Bus

InverterDiode AC

OutputVariable

FrequencyRectifier

L

C

Hydraulic

Pump

Valve

HydraulicMotor

ACMotor

Constant SpeedMotor

Types

of

Adjustable

Speed


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Drive Basics

AC Technology Comparison

Current Source Inverter

Variable Voltage Inverter

PWM Inverters

V/Hz Inverters

High Performance Vector Inverters


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Drive Basics

PWM INVERTER

Fixed DC Bus

DiodeRectifier

AC Input

L InverterC+


Benefits Constant input P.F. Wide speed range High efficiency (97 - 98%) Ride through options Open circuit protection Common bus regeneration Smooth low speed operation Vector control performance (optional)

Limitations Extra hardware for regeneration to line Motor noise (solved with IGBTs)

Possible Cable length limitations (with IGBTs)


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Drive Basics

PWM WAVEFORMS

0

0

Voltage

(Line to Neutral)

Current(Line)



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Drive Basics

Most Modern IGBT Power Switching

High peak current capability Very high switching frequency

Reduced switching losses



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Drive Basics

Bi-Polar Transistor vs. IGBT

1336 @ 60HZ NO LOAD

SWITCHING FREQUENCY1.26KHZ

1336 PLUS @ 60HZ

NO LOAD SWITCHING

FREQUENCY 9KHZ

Bi-Polar

IGBT


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Drive Basics

AC Drives BENEFITS

Low motor maintenance required

Decreased down time increases

production savings

Lower operating costs than DC

Quicker process response

increases production rates

Electric reversing = easier setup

and operation

Higher Motor Reliability

Lower installation cost

Increased up time

AC Drives vs. DC Drives AC Drives FEATURES

No commutator/brushes

AC motors are more available than DC

Power factor is constant across speed

range

Low rotating inertia per frame size

AC does not require reversing contactor

for reversing

AC motors offer more flexible motorenclosure

Individual isolation transformer not

required

AC available in bypass mode24


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Drive Basics

Choosing - Factors

Speed

Accuracy

Supply

Load

EnergyMaintenance

MotorProduction

FlexibilityInstallation/Space

Open / Closed Loop

Variable Torque

Constant Torque


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Drive Basics

Feature-Glossary

V/HzSkip-Frequency

DC-BrakeSignal Follower

Boost Preset Speeds

PWM-Frequency

Current LimitS-Curve

Speed Regulation

Motor OverloadMotor-Management

Communication

Speed Feedback

Accel/Decel


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Drive Basics

Themes - Glossary

EMC

Reflected Wave

Filter

Motorinsulation

Shielded Cable

HarmonicsGrounding

Motor cable lengthInstallation


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Drive Basics

Product Positioning - AC

AC Drive Products

1336Plus

160

1336Plus1305

1336FORCE

DefinitePurpose

GeneralPurpose

Gen. Purpose/High Perf.

AC SystemsDrive

1336IMPACT

High-Performance

1336IMPACT

SCANportFamily AC Drives

1336FORCE

what is a drive

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