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Copyright © 2005 Rockwell Automation, Inc. All rights reserved. 1
Motor Starting Technologies
Jack Smith – SYDJoe Pickell - RA
2 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Objective
• Review the basic motor starting technologies:– Across the line– Reduced voltage– Variable frequency
• Understand the selection criteria for each technology• Review application considerations for each starting technology
– Relative cost– Effects on available torque– Maintenance issues– Reliability
3 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Across The Line Starters
• Electromechanical or Solid State switch that closes the motor power circuit.– Motor is either on or off
• Various design standards exist for contactors– NEMA– IEC – Definite Purpose
• Characteristics– Motor has full voltage available as soon as power circuit closes
• Pulls an inrush current 5-7X Normal running current• Motor can produce full torque immediately
4 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Across the Line Starter - NEMA
Advantages•Available up to NEMA size 9, 1600HP @480VAC, 2250A•Simple design, few moving parts, reliable•Proven durability•Versions tested for various applications•Field serviceable•UL and CSA approved•Allen Bradley tested to 10 million operations
Limitations•Not touch safe•Physically large•Panel must be drilled and tapped to mount•Cannot be mounted significantly off vertical
5 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Across the Line Starter - IEC
Advantages•Available up to 860A, AC-3•Modular family includes:
•Overloads•MSP’s•Mounting Systems/Busbars
•Touch safe design•Versions tested for various applications•Space saving designs, mini versions available•DIN rail mounted•Global approvals
Limitations•Life span is application dependent•Typically 1 million operations at rated load•Limited field serviceability
Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Data NEMA IEC 18 AmpDescription Size 1 AC-3
HP Rating 10HP 10 HP
Life Operations 10 mil 2 mil
List Price $204 $130
Panel Area Required 21.4 in2 7.1 in2
IEC vs. NEMA Cost / Size / Life Comparison
Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Data NEMA IEC 18 A IEC 38 ADescription Size 1 AC-3 AC-3
HP Rating 10HP 10 HP 25HP
Life Operations 10 mil 2 mil 10 mil
List Price $204 $130 $210
Panel Area Required 21.4 in2 7.1 in2 14 in2
Life Comparison Equalizing Life
8 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Across the Line Starter – Definite Purpose
Advantages•Available up to 90A, 1,2or 3 pole versions•Specially tested to HVAC standards•Fast-on connections•DIN rail mounting available•Economically priced approx. 2/3 IEC $•UL and CSA approvals
Limitations•Life span is application dependent•Panel normally drilled and tapped•Very limited field serviceability•No matching overloads
9 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Across the Line Starter – Solid State
Advantages•Available up to 50A, AC-1 or 15A, AC-3•No moving parts•Touch safe design•Ideal for high duty cycle or high vibration applications•Ideal replacement for mercury contactors•DIN rail mounted•Global approvals
Limitations•Heat dissipation can be an issue•No field serviceable parts•No matching overloads•No aux contacts•Approx 1.5x IEC $
10 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Across the Line Starter – Vacuum
Advantages•Available up to 500HP @ 480 VAC, 600A•Long contact life due to vacuum•Ideal for high duty cycle applications•UL, CSA approvals
Limitations•Physical size may be an issue•Approx. 2x IEC $•Limited offering starting at 200A
11 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Overload Protection
Overload Relays for ATL Starters
12 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Motor running overcurrent protection
NEC article 430 - part C CEC rule 28-200 Reduce fire hazard
Comply with NEC/CEC
NEC Article 430
13 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Eutectic Alloy Type
Type W Heater Elements
• Adjust trip setting by installing various rated heater elements• Manual Reset only
14 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Thermal Memory
Type W Heater
Elements
Eutectic Alloy
Thermal MassResistance Element
To MotorTo Power
Ratchet Stud
Pawl to Mechanism Which Controls Relay
Contacts
15 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Eutectic Alloy Overload Relay Operation
Reset Position Tripped Position
EUTECTIC ALLOY
HEATER
PAWLRATCHET
PIVOT
CONTACTACTUATOR
CONTROLCIRCUIT
TOSTARTER
COIL
POWERCIRCUIT
POWERCIRCUIT
CONTROLCIRCUIT
TOSTARTER
COIL
16 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Bi-Metal Theory
Two metals with dissimilar expansion
Generated heating causes deflection
Adjustable trip setting
Manual or automatic reset
Bi Metallic
17 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Basic Electronic Overload
Advantages• Increased accuracy• Enhanced performance• Easy to select and apply• Greater application flexibility
18 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Product Overview
Feature Overview
Latching MechanismInsert MoldedPower Stabs
Reset ButtonTest Button
DIP Switches(193-EE, 592-EE only)
FLA Setting Dial
Mechanical Trip Actuator
Trip StatusIndicator
Control Terminals95 & 96 / 97 & 98
Load Terminations
19 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Product Overview
Wide 5:1 Adjustment Range• Application flexibility• Simplified product selection with a minimized number of catalog devices,
greater overlap• One device covers the range of 4 bimetallic overloads or 19 eutectic heater
elements
0.1A 90A
E1 Plus
Bimetal
20 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Proper Overload Protection
vs. Motor Life
21 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Reduced Voltage Starters
• Basic Functionality– Reduce inrush current during motor start– After start motor runs at full rated speed– Reduced starting torque = reduced mechanical wear – May provide energy savings if peak charges are an issue
• Electromechanical– Part Winding
• Used with special motors with parallel windings• Reduced starting torque
– Wye – Delta• Used with 6 lead delta wound motors• Reduced starting torque
– Autotransformer• Reduced starting torque vs. ATL but most per amp of above
• Solid State– Uses SCR’s to chop voltage peaks during start up– Electronic controls on SCR’s enable flexible starting profiles
22 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Economy Solid State Soft Starts
Advantages
• Up to 100HP @480VAc, 135A•Start ramp time selectable from 2 – 30 sec• Initial torque can be selected from 15% to 65%• Kick start can be selected to provide breakaway torque• Built in Overload protection• Diagnostics via flashing LED• Remote status via alarm contact• Ramp to stop
Limitations• No field serviceable parts
• Limited starting torque• 4 – 10 starts per hour
23 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
SMC-Flex
Advantages
• Up to 400HP @ 480VAC, 480A•Programmable ramp time• Special pump control algorithm available• Preset slow speed capable• Can do full voltage start• Built in Electronic Overload protection• Diagnostics via local message display or comms• Remote status via alarm contacts or comms• Smart motor braking optional;
Limitations• Limited starting torque
•
Full Featured Solid State Soft Starts
24 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Variable Frequency Drives
• Basic Functionality– Offers total speed control including ramp
up and down– Speed controlled by changing frequency of
power to motor– Speed control may result in energy savings
• Component class drives– Power Flex 4– Power Flex 40– Power Flex 400
• Architecture Class Drives– Power Flex 70– Power Flex 700
25 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Optimized for machine-level and stand-alone control• Most economical
Allen-Bradley offering in its power, performance & feature segment
• Simple selection, set-up, & operation
• Industry-standard RS-485 communications capabilities
• Industry-standard power structure features & installation options P
erfo
rman
ce /
Fu
nct
ion
alit
y
Power Rating (HP @ 460V)
5 10 20 50 200
PowerFlex 400 PowerFlex 40
PowerFlex 4
100
“4-Class”
Products
“Component Class” Drives
26 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Component Drive Applications
• Provides a smooth accel/decel – no jerky motion
• Fixed acceleration using variable frequency– Important when synchronizing machines or
processes
• Speed changes “on the fly”• Communication status across network• Critical stopping criteria –
– For repeatable and accurate “in position” applications
27 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Rockwell Automation Strengths
• The most simple to use product in its class• Integral keypad with control keys and local pot active out of the box• DIN rail mounting, small package size, Zero Stacking
• Same integral keypad as PowerFlex 4• Expanded I/O, sensorless vector control, add on communications options
and timer/counter/Step Logic functionality
• PowerFlex 400 is the HVAC drive with standard features aimed at the centrifugal pump and fan marketplace
28 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Integral LED Keypad Simplifies Start Up
• 4 digit LED display indicates parameter number or value • LED indicators for run and direction status• LED indicators for units of parameter values• Programming keys similar to all other PowerFlex products• Three simple programming groups
– Display Group– Basic Group– Advanced Group
29 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Drive Commissioning Made Simple
• Just hook up your power wiring and control the drive from the integral keypad
– Control keys are active allowing out of the box operation. Status indicators above start key and speed pot indicate when active.
• 10 most common application parameters contained in Basic Program Group to simplify programming
– P031 Motor Nameplate Voltage– P032 Motor Nameplate Frequency– P033 Motor Overload Current– P034 Minimum Frequency– P035 Maximum Frequency– P036 Start Source– P037 Stop Mode– P038 Speed Reference– P039 Accel Time 1– P040 Decel Time 1
30 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
PowerFlex 40 – Increased Performance
• Excellent motor control, thru 7.5 kW / 15 HP– V/Hz or Sensorless Vector (SVC) modes
• Communication– Integral RS485 serial communication– Add-on communication adapters
• Expanded I/O– Analog output– 2 digital outputs
• Logic Functions– Timer– Counter– StepLogic
• Similar to PowerFlex4− Common parameter structure & set-up– Integral user interface– Common “4 Class” accessories
31 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Relative Cost Comparison 5-50HP
DP IEC NEMASS
Contactor
SS Reduced Voltage VFD
5HP 0.7 1.0 2.3 1.5 3.7 8.0
15HP 0.6 1.0 3.4 1.0 3.1 11.8
30HP 0.8 1.0 4.5 3.8 8.5
50HP 0.9 1.0 2.2 4.3 13.0
32 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Relative Cost Comparison 75 – 200HP
IEC NEMA Vacuum
SS Reduced Voltage VFD
75HP 1.0 3.9 5.5 5.5 12.9
100HP 1.0 2.4 3.3 4.4 9.6
150HP 1.0 3.1 2.0 3.1 8.0
200HP 1.0 2.7 3.1 3.0 11.2
33 Copyright © 2005 Rockwell Automation, Inc. All rights reserved.
Copyright © 2005 Rockwell Automation, Inc. All rights reserved. 34