motor controllers & drives
TRANSCRIPT
MOTOR CONTROLLERSamp DRIVESBUYING GUIDE
For more Buying Guides visit WWWTHOMASNETCOMIndustryrsquos go to Platform for Supplier Discovery
MOTOR CONTROLLERS AND DRIVES A ThomasNet Buying Guide
Motor Controllers and Drives are electrical or electronic
devices that regulate motor speed torque and position
outputs The drive modifies the power input to the motor to achieve the desired output The controller
circuits are commonly integrated with the drive circuits as one stand-alone unit thus the terms motor
drive and motor controller are frequently used interchangeably There are four basic motor controller
and drive types AC DC servo and stepper each having an input power type modified to a desired
output function to match with an application
Motor Controller and Drive Types
AC AC Motor Controllers and Drives are electronic devices that modify
the input power to motors by typically adjusting the frequency of the
power to the motor for the purpose of regulating the output speed
and torque Key specifications include the intended application drive
operating mode motor type inverter type loop system voltage
classification power rating communication interface as well as
input and output electrical specifications AC motor controllers and
drives are used primarily in process applications to control the speed
of pumps fans blowers etc They are known as variable speed
drives adjustable frequency drives or AC inverters The controller
commonly integrated with the drive circuits supplies the control
signals to the drive
DC DC Motor Controllers and Drives are electrical devices that modify the
input power by adjusting the constant or alternating current source to a
pulsed direct current output of varying pulse duration or frequency Key
specifications include the intended application drive operating mode
motor type loop system voltage classification power rating output signal
type communication interface as well as input and output electrical
specifications DC motor controllers and drives are used primarily to
control motor speeds and torques for machine tools electric vehicles
pumps etc The controller commonly integrated with the drive circuits supplies the control signals to
the drive
Servomotor Servo Motor Controllers and Drives are electronic devices that modify
the input power by adjusting the constant or alternating current source
to a pulsed current output of varying pulse duration or frequency Key
specifications include the intended application motor type drive
operating mode loop system power rating output signal type
communication interface as well as electrical specifications Servo
motor controllers and drives are used primarily in motion control
applications in manufacturing and construction environments among
others and used to control motor speeds torques and positions and may be AC or DC driven Servo
motors are used in many applications including machine tools micro-positioning and robotics among
many other types of machinery such as conveyors or spindle drive systems The controller commonly
integrated with the drive circuits supplies the control signals to the drive Servo drives are also known
as servomotor amplifiers
Stepper Stepper Motor Controllers and Drives are electronic devices that modify the input power by adjusting
the constant or alternating current source to a pulsed or stepped current output
Key specifications include the intended application motor type drive
operating mode loop system power rating output signal type
communication interface as well as electrical specifications
Stepper motor controllers and drives are used primarily in motion
control applications in manufacturing and construction environments
among others and used to control motor speeds torques and
position They are used in many applications including machine tools
micro-positioning and robotics among many other types of
machinery such as conveyors or OEM equipment The controller
commonly integrated with the drive circuits supplies the control signals to the drive Stepper drives are
also known as pulse drives and step amplifiers Stepper controllers are also known as motor indexers
Applications and Industries
Unlike servomotors and steppers most AC and DC motors donrsquot require controllers or drives other than
the simplest motor starters and similar protective devices AC motor drives are used when speed control
of an AC motor is desirable because controlling speed in an AC induction motor is not normally donemdash
once a motor has been specified (by number of poles) the operating speed is stated on the nameplate
Brushed DC motors on the other hand are fundamentally speed controllable by merely varying the
voltage going to the motor rotor and field This can be accomplished with a simple rheostat no
controller or drive is necessary Newer brushless DC motors are not mechanically commutated and
hence require controllers and drives to commutate the magnetic field electronically Servomotors and
steppers because they are positioning devices as opposed to rotary motion machines also require
controllers and drivers for their operation
AC motors drives are used to control the speeds of motors that drive pumps fans etc where traditional
valves or dampers might otherwise be used to throttle the flow AC motor drives are used to increase
efficiency by setting pump fan etc speed to exactly match requirements
DC motor drives are used to control permanent magnet DC motors running from AC sources DC motors
have very good low speed torque making them especially suited to winches cranes etc where loads
have to be lifted without a ldquorunning startrdquo Before the advent of electronic DC controls DC motors we
often coupled as motor-generator sets to produce DC current via AC
induction motors
Servomotor controllers and drives rely on feedback from the
servomotors to control position velocity acceleration etc Servomotor
manufacturers generally supply drives that work with their motors
While steppers donrsquot require a feedback loop some use one Stepper
motor makers also usually supply drives for their specific motors Most
servo- and stepper-motor manufacturers provide charts as guides to
which motors will work with which drives
Considerations Choosing motor controllers and drives starts with knowing the motor type Corresponding sub-
categories then align with this basic information
Deciding to use AC drives for induction motors is often an economic decision based on operating
characteristics at specific installations how often the pump or fan is running against throttled valves or
louvered ducts At least one manufacturer offers a calculator (see below) to help determine energy
savings of AC drives based on specific operating scenarios Motors designed for use with variable speed
drives are typically rated for inverter duty
Another consideration for AC drives is the nature of the application with constant torque and variable
torque being major divisions For variable torque applications such as centrifugal fans torque
requirements vary with motor speed For constant torque applications such as conveyors torque
requirements are the same regardless of motor speed AC drives are usually designed for either variable
or constant speed applications
Brushed DC motors running off AC current usually are driven using thyristor-based bridge rectifiers ehich
permit AC current to flow to the motor in one direction only replicating a DC power source More can
be found in the references below Vendors such as Baldor provide DC controls for one way and
regenerative applications for DC motor horsepowers up to 5 and through its parent company (ABB)
offers DC drives up to 3000 HP One-way drives usually require a brake for stopping the motor while
regenerative drives can run the motor in either direction and so provide stopping force by reversing
Generated power is usually bled off through reversing resistors
Brushed DC motors operating on DC systems such as found on electric pallet jacks also use controls for
speed and directional changes Brushless DC or permanent magnet motors also require controllers to
electronically commutate their magnetic fields
Servomotors can be of AC or DC types with DC available as brush and brushless types In all instances
they require controls because they are feedback devices Linear motors are generally servo-based and
require controls too
Stepper motors generally do not require feedback but must be ldquohomedrdquo upon powering up so that the
motor knows where it is From there it counts steps to keep track of position Some steppers piggyback
their drives directly on the motor frames
Important Attributes
Semiconductor Device Generally speaking IGBTs and SCRs are used for medium and high voltage devices while MOSFETs are
used in low power applications
Motor Input Phase Motors are generally single or three phase machines referring to the phase of the alternating current
that supplies them Stepper motors are an exception in this regard because phase refers to the
architecture of the stepper motor itself generally described as two or five phase Oriental Motors has a
nice write up discussing the difference cited below
Enclosure Electrical enclosures are specified in accordance with NEMA or IEC criteria for environmental and ingress
protection
Drive Operating Mode As discussed above AC drives are generally designed either as constant torque or variable torque
depending on the application
Related Product Categories
Motors see our Motors Buying Guide
Motor Starters see our Motor Starters Buying Guide
Resources
General Trade groups httpwwwsmmaorgindexhtm httpwwwmotioncontrolonlineorgi4apagesindexcfmpageid=3283 A pump and fan energy saving calculator for evaluating AC variable speed drives httpwwwrockwellenergycalccom A technical discussion of DC motors and drives httpcmsappsseasiemenscomsteppdfsdc_drivespdf Two-phase v five-phase stepper motor comparison httpwwworientalmotorcomtechnologyarticles2phase-v-5phasehtml
Manufacturers and Suppliers httpcatalogorientalmotorcom httpproductsautonicsonlinecomcategorymotion-devices httpcataloge-jpccom httprepair-searchschneiderelectricrepaircomcategoryby-product-type httpservolinearcomthomasnet-navigatorcomproductservo-drive-componentspositioning-controller httpmotionsystemspi-usaus httpbaldorthomasnetcom httpcatalogjamiesonequipmentcomcategoryrs-motor-controls-and-gear-reducers-motor-controls httpcataloge-jpccom httpboydelectricalstagethomasnet-navigatorcom httpcookindustrialthomasnetcomviewitemsindustrial-parts-vfd-s-inverters-cerus-invertersampbc=100|1025|1027 httpcatalogkofflercomcategoryvariable-frequency-drivesampbc=1007C1279 httpwwwgamainccomrc httpautovacthomasnet-navigatorcomcategoryadvanced-motor-controls-software httpdc-drives-motorsgrahammotorsandcontrolscomcategorydc-motor-controllers httpbodineelethomasnetcom httpproductsfifepearcecomcategoryproduct-catalog httpspindle-catalogtdmusaspindlescomcategoryhigh-speed-motor-drives httpcatalogpowertechcontrolscomcategorys-abb-control-abb-drives-abb-low-voltage-ac-drives httppumpsrapidservicecomcategoryyaskawa-vfd-drives
MOTOR CONTROLLERS AND DRIVES A ThomasNet Buying Guide
Motor Controllers and Drives are electrical or electronic
devices that regulate motor speed torque and position
outputs The drive modifies the power input to the motor to achieve the desired output The controller
circuits are commonly integrated with the drive circuits as one stand-alone unit thus the terms motor
drive and motor controller are frequently used interchangeably There are four basic motor controller
and drive types AC DC servo and stepper each having an input power type modified to a desired
output function to match with an application
Motor Controller and Drive Types
AC AC Motor Controllers and Drives are electronic devices that modify
the input power to motors by typically adjusting the frequency of the
power to the motor for the purpose of regulating the output speed
and torque Key specifications include the intended application drive
operating mode motor type inverter type loop system voltage
classification power rating communication interface as well as
input and output electrical specifications AC motor controllers and
drives are used primarily in process applications to control the speed
of pumps fans blowers etc They are known as variable speed
drives adjustable frequency drives or AC inverters The controller
commonly integrated with the drive circuits supplies the control
signals to the drive
DC DC Motor Controllers and Drives are electrical devices that modify the
input power by adjusting the constant or alternating current source to a
pulsed direct current output of varying pulse duration or frequency Key
specifications include the intended application drive operating mode
motor type loop system voltage classification power rating output signal
type communication interface as well as input and output electrical
specifications DC motor controllers and drives are used primarily to
control motor speeds and torques for machine tools electric vehicles
pumps etc The controller commonly integrated with the drive circuits supplies the control signals to
the drive
Servomotor Servo Motor Controllers and Drives are electronic devices that modify
the input power by adjusting the constant or alternating current source
to a pulsed current output of varying pulse duration or frequency Key
specifications include the intended application motor type drive
operating mode loop system power rating output signal type
communication interface as well as electrical specifications Servo
motor controllers and drives are used primarily in motion control
applications in manufacturing and construction environments among
others and used to control motor speeds torques and positions and may be AC or DC driven Servo
motors are used in many applications including machine tools micro-positioning and robotics among
many other types of machinery such as conveyors or spindle drive systems The controller commonly
integrated with the drive circuits supplies the control signals to the drive Servo drives are also known
as servomotor amplifiers
Stepper Stepper Motor Controllers and Drives are electronic devices that modify the input power by adjusting
the constant or alternating current source to a pulsed or stepped current output
Key specifications include the intended application motor type drive
operating mode loop system power rating output signal type
communication interface as well as electrical specifications
Stepper motor controllers and drives are used primarily in motion
control applications in manufacturing and construction environments
among others and used to control motor speeds torques and
position They are used in many applications including machine tools
micro-positioning and robotics among many other types of
machinery such as conveyors or OEM equipment The controller
commonly integrated with the drive circuits supplies the control signals to the drive Stepper drives are
also known as pulse drives and step amplifiers Stepper controllers are also known as motor indexers
Applications and Industries
Unlike servomotors and steppers most AC and DC motors donrsquot require controllers or drives other than
the simplest motor starters and similar protective devices AC motor drives are used when speed control
of an AC motor is desirable because controlling speed in an AC induction motor is not normally donemdash
once a motor has been specified (by number of poles) the operating speed is stated on the nameplate
Brushed DC motors on the other hand are fundamentally speed controllable by merely varying the
voltage going to the motor rotor and field This can be accomplished with a simple rheostat no
controller or drive is necessary Newer brushless DC motors are not mechanically commutated and
hence require controllers and drives to commutate the magnetic field electronically Servomotors and
steppers because they are positioning devices as opposed to rotary motion machines also require
controllers and drivers for their operation
AC motors drives are used to control the speeds of motors that drive pumps fans etc where traditional
valves or dampers might otherwise be used to throttle the flow AC motor drives are used to increase
efficiency by setting pump fan etc speed to exactly match requirements
DC motor drives are used to control permanent magnet DC motors running from AC sources DC motors
have very good low speed torque making them especially suited to winches cranes etc where loads
have to be lifted without a ldquorunning startrdquo Before the advent of electronic DC controls DC motors we
often coupled as motor-generator sets to produce DC current via AC
induction motors
Servomotor controllers and drives rely on feedback from the
servomotors to control position velocity acceleration etc Servomotor
manufacturers generally supply drives that work with their motors
While steppers donrsquot require a feedback loop some use one Stepper
motor makers also usually supply drives for their specific motors Most
servo- and stepper-motor manufacturers provide charts as guides to
which motors will work with which drives
Considerations Choosing motor controllers and drives starts with knowing the motor type Corresponding sub-
categories then align with this basic information
Deciding to use AC drives for induction motors is often an economic decision based on operating
characteristics at specific installations how often the pump or fan is running against throttled valves or
louvered ducts At least one manufacturer offers a calculator (see below) to help determine energy
savings of AC drives based on specific operating scenarios Motors designed for use with variable speed
drives are typically rated for inverter duty
Another consideration for AC drives is the nature of the application with constant torque and variable
torque being major divisions For variable torque applications such as centrifugal fans torque
requirements vary with motor speed For constant torque applications such as conveyors torque
requirements are the same regardless of motor speed AC drives are usually designed for either variable
or constant speed applications
Brushed DC motors running off AC current usually are driven using thyristor-based bridge rectifiers ehich
permit AC current to flow to the motor in one direction only replicating a DC power source More can
be found in the references below Vendors such as Baldor provide DC controls for one way and
regenerative applications for DC motor horsepowers up to 5 and through its parent company (ABB)
offers DC drives up to 3000 HP One-way drives usually require a brake for stopping the motor while
regenerative drives can run the motor in either direction and so provide stopping force by reversing
Generated power is usually bled off through reversing resistors
Brushed DC motors operating on DC systems such as found on electric pallet jacks also use controls for
speed and directional changes Brushless DC or permanent magnet motors also require controllers to
electronically commutate their magnetic fields
Servomotors can be of AC or DC types with DC available as brush and brushless types In all instances
they require controls because they are feedback devices Linear motors are generally servo-based and
require controls too
Stepper motors generally do not require feedback but must be ldquohomedrdquo upon powering up so that the
motor knows where it is From there it counts steps to keep track of position Some steppers piggyback
their drives directly on the motor frames
Important Attributes
Semiconductor Device Generally speaking IGBTs and SCRs are used for medium and high voltage devices while MOSFETs are
used in low power applications
Motor Input Phase Motors are generally single or three phase machines referring to the phase of the alternating current
that supplies them Stepper motors are an exception in this regard because phase refers to the
architecture of the stepper motor itself generally described as two or five phase Oriental Motors has a
nice write up discussing the difference cited below
Enclosure Electrical enclosures are specified in accordance with NEMA or IEC criteria for environmental and ingress
protection
Drive Operating Mode As discussed above AC drives are generally designed either as constant torque or variable torque
depending on the application
Related Product Categories
Motors see our Motors Buying Guide
Motor Starters see our Motor Starters Buying Guide
Resources
General Trade groups httpwwwsmmaorgindexhtm httpwwwmotioncontrolonlineorgi4apagesindexcfmpageid=3283 A pump and fan energy saving calculator for evaluating AC variable speed drives httpwwwrockwellenergycalccom A technical discussion of DC motors and drives httpcmsappsseasiemenscomsteppdfsdc_drivespdf Two-phase v five-phase stepper motor comparison httpwwworientalmotorcomtechnologyarticles2phase-v-5phasehtml
Manufacturers and Suppliers httpcatalogorientalmotorcom httpproductsautonicsonlinecomcategorymotion-devices httpcataloge-jpccom httprepair-searchschneiderelectricrepaircomcategoryby-product-type httpservolinearcomthomasnet-navigatorcomproductservo-drive-componentspositioning-controller httpmotionsystemspi-usaus httpbaldorthomasnetcom httpcatalogjamiesonequipmentcomcategoryrs-motor-controls-and-gear-reducers-motor-controls httpcataloge-jpccom httpboydelectricalstagethomasnet-navigatorcom httpcookindustrialthomasnetcomviewitemsindustrial-parts-vfd-s-inverters-cerus-invertersampbc=100|1025|1027 httpcatalogkofflercomcategoryvariable-frequency-drivesampbc=1007C1279 httpwwwgamainccomrc httpautovacthomasnet-navigatorcomcategoryadvanced-motor-controls-software httpdc-drives-motorsgrahammotorsandcontrolscomcategorydc-motor-controllers httpbodineelethomasnetcom httpproductsfifepearcecomcategoryproduct-catalog httpspindle-catalogtdmusaspindlescomcategoryhigh-speed-motor-drives httpcatalogpowertechcontrolscomcategorys-abb-control-abb-drives-abb-low-voltage-ac-drives httppumpsrapidservicecomcategoryyaskawa-vfd-drives
pumps etc The controller commonly integrated with the drive circuits supplies the control signals to
the drive
Servomotor Servo Motor Controllers and Drives are electronic devices that modify
the input power by adjusting the constant or alternating current source
to a pulsed current output of varying pulse duration or frequency Key
specifications include the intended application motor type drive
operating mode loop system power rating output signal type
communication interface as well as electrical specifications Servo
motor controllers and drives are used primarily in motion control
applications in manufacturing and construction environments among
others and used to control motor speeds torques and positions and may be AC or DC driven Servo
motors are used in many applications including machine tools micro-positioning and robotics among
many other types of machinery such as conveyors or spindle drive systems The controller commonly
integrated with the drive circuits supplies the control signals to the drive Servo drives are also known
as servomotor amplifiers
Stepper Stepper Motor Controllers and Drives are electronic devices that modify the input power by adjusting
the constant or alternating current source to a pulsed or stepped current output
Key specifications include the intended application motor type drive
operating mode loop system power rating output signal type
communication interface as well as electrical specifications
Stepper motor controllers and drives are used primarily in motion
control applications in manufacturing and construction environments
among others and used to control motor speeds torques and
position They are used in many applications including machine tools
micro-positioning and robotics among many other types of
machinery such as conveyors or OEM equipment The controller
commonly integrated with the drive circuits supplies the control signals to the drive Stepper drives are
also known as pulse drives and step amplifiers Stepper controllers are also known as motor indexers
Applications and Industries
Unlike servomotors and steppers most AC and DC motors donrsquot require controllers or drives other than
the simplest motor starters and similar protective devices AC motor drives are used when speed control
of an AC motor is desirable because controlling speed in an AC induction motor is not normally donemdash
once a motor has been specified (by number of poles) the operating speed is stated on the nameplate
Brushed DC motors on the other hand are fundamentally speed controllable by merely varying the
voltage going to the motor rotor and field This can be accomplished with a simple rheostat no
controller or drive is necessary Newer brushless DC motors are not mechanically commutated and
hence require controllers and drives to commutate the magnetic field electronically Servomotors and
steppers because they are positioning devices as opposed to rotary motion machines also require
controllers and drivers for their operation
AC motors drives are used to control the speeds of motors that drive pumps fans etc where traditional
valves or dampers might otherwise be used to throttle the flow AC motor drives are used to increase
efficiency by setting pump fan etc speed to exactly match requirements
DC motor drives are used to control permanent magnet DC motors running from AC sources DC motors
have very good low speed torque making them especially suited to winches cranes etc where loads
have to be lifted without a ldquorunning startrdquo Before the advent of electronic DC controls DC motors we
often coupled as motor-generator sets to produce DC current via AC
induction motors
Servomotor controllers and drives rely on feedback from the
servomotors to control position velocity acceleration etc Servomotor
manufacturers generally supply drives that work with their motors
While steppers donrsquot require a feedback loop some use one Stepper
motor makers also usually supply drives for their specific motors Most
servo- and stepper-motor manufacturers provide charts as guides to
which motors will work with which drives
Considerations Choosing motor controllers and drives starts with knowing the motor type Corresponding sub-
categories then align with this basic information
Deciding to use AC drives for induction motors is often an economic decision based on operating
characteristics at specific installations how often the pump or fan is running against throttled valves or
louvered ducts At least one manufacturer offers a calculator (see below) to help determine energy
savings of AC drives based on specific operating scenarios Motors designed for use with variable speed
drives are typically rated for inverter duty
Another consideration for AC drives is the nature of the application with constant torque and variable
torque being major divisions For variable torque applications such as centrifugal fans torque
requirements vary with motor speed For constant torque applications such as conveyors torque
requirements are the same regardless of motor speed AC drives are usually designed for either variable
or constant speed applications
Brushed DC motors running off AC current usually are driven using thyristor-based bridge rectifiers ehich
permit AC current to flow to the motor in one direction only replicating a DC power source More can
be found in the references below Vendors such as Baldor provide DC controls for one way and
regenerative applications for DC motor horsepowers up to 5 and through its parent company (ABB)
offers DC drives up to 3000 HP One-way drives usually require a brake for stopping the motor while
regenerative drives can run the motor in either direction and so provide stopping force by reversing
Generated power is usually bled off through reversing resistors
Brushed DC motors operating on DC systems such as found on electric pallet jacks also use controls for
speed and directional changes Brushless DC or permanent magnet motors also require controllers to
electronically commutate their magnetic fields
Servomotors can be of AC or DC types with DC available as brush and brushless types In all instances
they require controls because they are feedback devices Linear motors are generally servo-based and
require controls too
Stepper motors generally do not require feedback but must be ldquohomedrdquo upon powering up so that the
motor knows where it is From there it counts steps to keep track of position Some steppers piggyback
their drives directly on the motor frames
Important Attributes
Semiconductor Device Generally speaking IGBTs and SCRs are used for medium and high voltage devices while MOSFETs are
used in low power applications
Motor Input Phase Motors are generally single or three phase machines referring to the phase of the alternating current
that supplies them Stepper motors are an exception in this regard because phase refers to the
architecture of the stepper motor itself generally described as two or five phase Oriental Motors has a
nice write up discussing the difference cited below
Enclosure Electrical enclosures are specified in accordance with NEMA or IEC criteria for environmental and ingress
protection
Drive Operating Mode As discussed above AC drives are generally designed either as constant torque or variable torque
depending on the application
Related Product Categories
Motors see our Motors Buying Guide
Motor Starters see our Motor Starters Buying Guide
Resources
General Trade groups httpwwwsmmaorgindexhtm httpwwwmotioncontrolonlineorgi4apagesindexcfmpageid=3283 A pump and fan energy saving calculator for evaluating AC variable speed drives httpwwwrockwellenergycalccom A technical discussion of DC motors and drives httpcmsappsseasiemenscomsteppdfsdc_drivespdf Two-phase v five-phase stepper motor comparison httpwwworientalmotorcomtechnologyarticles2phase-v-5phasehtml
Manufacturers and Suppliers httpcatalogorientalmotorcom httpproductsautonicsonlinecomcategorymotion-devices httpcataloge-jpccom httprepair-searchschneiderelectricrepaircomcategoryby-product-type httpservolinearcomthomasnet-navigatorcomproductservo-drive-componentspositioning-controller httpmotionsystemspi-usaus httpbaldorthomasnetcom httpcatalogjamiesonequipmentcomcategoryrs-motor-controls-and-gear-reducers-motor-controls httpcataloge-jpccom httpboydelectricalstagethomasnet-navigatorcom httpcookindustrialthomasnetcomviewitemsindustrial-parts-vfd-s-inverters-cerus-invertersampbc=100|1025|1027 httpcatalogkofflercomcategoryvariable-frequency-drivesampbc=1007C1279 httpwwwgamainccomrc httpautovacthomasnet-navigatorcomcategoryadvanced-motor-controls-software httpdc-drives-motorsgrahammotorsandcontrolscomcategorydc-motor-controllers httpbodineelethomasnetcom httpproductsfifepearcecomcategoryproduct-catalog httpspindle-catalogtdmusaspindlescomcategoryhigh-speed-motor-drives httpcatalogpowertechcontrolscomcategorys-abb-control-abb-drives-abb-low-voltage-ac-drives httppumpsrapidservicecomcategoryyaskawa-vfd-drives
hence require controllers and drives to commutate the magnetic field electronically Servomotors and
steppers because they are positioning devices as opposed to rotary motion machines also require
controllers and drivers for their operation
AC motors drives are used to control the speeds of motors that drive pumps fans etc where traditional
valves or dampers might otherwise be used to throttle the flow AC motor drives are used to increase
efficiency by setting pump fan etc speed to exactly match requirements
DC motor drives are used to control permanent magnet DC motors running from AC sources DC motors
have very good low speed torque making them especially suited to winches cranes etc where loads
have to be lifted without a ldquorunning startrdquo Before the advent of electronic DC controls DC motors we
often coupled as motor-generator sets to produce DC current via AC
induction motors
Servomotor controllers and drives rely on feedback from the
servomotors to control position velocity acceleration etc Servomotor
manufacturers generally supply drives that work with their motors
While steppers donrsquot require a feedback loop some use one Stepper
motor makers also usually supply drives for their specific motors Most
servo- and stepper-motor manufacturers provide charts as guides to
which motors will work with which drives
Considerations Choosing motor controllers and drives starts with knowing the motor type Corresponding sub-
categories then align with this basic information
Deciding to use AC drives for induction motors is often an economic decision based on operating
characteristics at specific installations how often the pump or fan is running against throttled valves or
louvered ducts At least one manufacturer offers a calculator (see below) to help determine energy
savings of AC drives based on specific operating scenarios Motors designed for use with variable speed
drives are typically rated for inverter duty
Another consideration for AC drives is the nature of the application with constant torque and variable
torque being major divisions For variable torque applications such as centrifugal fans torque
requirements vary with motor speed For constant torque applications such as conveyors torque
requirements are the same regardless of motor speed AC drives are usually designed for either variable
or constant speed applications
Brushed DC motors running off AC current usually are driven using thyristor-based bridge rectifiers ehich
permit AC current to flow to the motor in one direction only replicating a DC power source More can
be found in the references below Vendors such as Baldor provide DC controls for one way and
regenerative applications for DC motor horsepowers up to 5 and through its parent company (ABB)
offers DC drives up to 3000 HP One-way drives usually require a brake for stopping the motor while
regenerative drives can run the motor in either direction and so provide stopping force by reversing
Generated power is usually bled off through reversing resistors
Brushed DC motors operating on DC systems such as found on electric pallet jacks also use controls for
speed and directional changes Brushless DC or permanent magnet motors also require controllers to
electronically commutate their magnetic fields
Servomotors can be of AC or DC types with DC available as brush and brushless types In all instances
they require controls because they are feedback devices Linear motors are generally servo-based and
require controls too
Stepper motors generally do not require feedback but must be ldquohomedrdquo upon powering up so that the
motor knows where it is From there it counts steps to keep track of position Some steppers piggyback
their drives directly on the motor frames
Important Attributes
Semiconductor Device Generally speaking IGBTs and SCRs are used for medium and high voltage devices while MOSFETs are
used in low power applications
Motor Input Phase Motors are generally single or three phase machines referring to the phase of the alternating current
that supplies them Stepper motors are an exception in this regard because phase refers to the
architecture of the stepper motor itself generally described as two or five phase Oriental Motors has a
nice write up discussing the difference cited below
Enclosure Electrical enclosures are specified in accordance with NEMA or IEC criteria for environmental and ingress
protection
Drive Operating Mode As discussed above AC drives are generally designed either as constant torque or variable torque
depending on the application
Related Product Categories
Motors see our Motors Buying Guide
Motor Starters see our Motor Starters Buying Guide
Resources
General Trade groups httpwwwsmmaorgindexhtm httpwwwmotioncontrolonlineorgi4apagesindexcfmpageid=3283 A pump and fan energy saving calculator for evaluating AC variable speed drives httpwwwrockwellenergycalccom A technical discussion of DC motors and drives httpcmsappsseasiemenscomsteppdfsdc_drivespdf Two-phase v five-phase stepper motor comparison httpwwworientalmotorcomtechnologyarticles2phase-v-5phasehtml
Manufacturers and Suppliers httpcatalogorientalmotorcom httpproductsautonicsonlinecomcategorymotion-devices httpcataloge-jpccom httprepair-searchschneiderelectricrepaircomcategoryby-product-type httpservolinearcomthomasnet-navigatorcomproductservo-drive-componentspositioning-controller httpmotionsystemspi-usaus httpbaldorthomasnetcom httpcatalogjamiesonequipmentcomcategoryrs-motor-controls-and-gear-reducers-motor-controls httpcataloge-jpccom httpboydelectricalstagethomasnet-navigatorcom httpcookindustrialthomasnetcomviewitemsindustrial-parts-vfd-s-inverters-cerus-invertersampbc=100|1025|1027 httpcatalogkofflercomcategoryvariable-frequency-drivesampbc=1007C1279 httpwwwgamainccomrc httpautovacthomasnet-navigatorcomcategoryadvanced-motor-controls-software httpdc-drives-motorsgrahammotorsandcontrolscomcategorydc-motor-controllers httpbodineelethomasnetcom httpproductsfifepearcecomcategoryproduct-catalog httpspindle-catalogtdmusaspindlescomcategoryhigh-speed-motor-drives httpcatalogpowertechcontrolscomcategorys-abb-control-abb-drives-abb-low-voltage-ac-drives httppumpsrapidservicecomcategoryyaskawa-vfd-drives
regenerative drives can run the motor in either direction and so provide stopping force by reversing
Generated power is usually bled off through reversing resistors
Brushed DC motors operating on DC systems such as found on electric pallet jacks also use controls for
speed and directional changes Brushless DC or permanent magnet motors also require controllers to
electronically commutate their magnetic fields
Servomotors can be of AC or DC types with DC available as brush and brushless types In all instances
they require controls because they are feedback devices Linear motors are generally servo-based and
require controls too
Stepper motors generally do not require feedback but must be ldquohomedrdquo upon powering up so that the
motor knows where it is From there it counts steps to keep track of position Some steppers piggyback
their drives directly on the motor frames
Important Attributes
Semiconductor Device Generally speaking IGBTs and SCRs are used for medium and high voltage devices while MOSFETs are
used in low power applications
Motor Input Phase Motors are generally single or three phase machines referring to the phase of the alternating current
that supplies them Stepper motors are an exception in this regard because phase refers to the
architecture of the stepper motor itself generally described as two or five phase Oriental Motors has a
nice write up discussing the difference cited below
Enclosure Electrical enclosures are specified in accordance with NEMA or IEC criteria for environmental and ingress
protection
Drive Operating Mode As discussed above AC drives are generally designed either as constant torque or variable torque
depending on the application
Related Product Categories
Motors see our Motors Buying Guide
Motor Starters see our Motor Starters Buying Guide
Resources
General Trade groups httpwwwsmmaorgindexhtm httpwwwmotioncontrolonlineorgi4apagesindexcfmpageid=3283 A pump and fan energy saving calculator for evaluating AC variable speed drives httpwwwrockwellenergycalccom A technical discussion of DC motors and drives httpcmsappsseasiemenscomsteppdfsdc_drivespdf Two-phase v five-phase stepper motor comparison httpwwworientalmotorcomtechnologyarticles2phase-v-5phasehtml
Manufacturers and Suppliers httpcatalogorientalmotorcom httpproductsautonicsonlinecomcategorymotion-devices httpcataloge-jpccom httprepair-searchschneiderelectricrepaircomcategoryby-product-type httpservolinearcomthomasnet-navigatorcomproductservo-drive-componentspositioning-controller httpmotionsystemspi-usaus httpbaldorthomasnetcom httpcatalogjamiesonequipmentcomcategoryrs-motor-controls-and-gear-reducers-motor-controls httpcataloge-jpccom httpboydelectricalstagethomasnet-navigatorcom httpcookindustrialthomasnetcomviewitemsindustrial-parts-vfd-s-inverters-cerus-invertersampbc=100|1025|1027 httpcatalogkofflercomcategoryvariable-frequency-drivesampbc=1007C1279 httpwwwgamainccomrc httpautovacthomasnet-navigatorcomcategoryadvanced-motor-controls-software httpdc-drives-motorsgrahammotorsandcontrolscomcategorydc-motor-controllers httpbodineelethomasnetcom httpproductsfifepearcecomcategoryproduct-catalog httpspindle-catalogtdmusaspindlescomcategoryhigh-speed-motor-drives httpcatalogpowertechcontrolscomcategorys-abb-control-abb-drives-abb-low-voltage-ac-drives httppumpsrapidservicecomcategoryyaskawa-vfd-drives
Resources
General Trade groups httpwwwsmmaorgindexhtm httpwwwmotioncontrolonlineorgi4apagesindexcfmpageid=3283 A pump and fan energy saving calculator for evaluating AC variable speed drives httpwwwrockwellenergycalccom A technical discussion of DC motors and drives httpcmsappsseasiemenscomsteppdfsdc_drivespdf Two-phase v five-phase stepper motor comparison httpwwworientalmotorcomtechnologyarticles2phase-v-5phasehtml
Manufacturers and Suppliers httpcatalogorientalmotorcom httpproductsautonicsonlinecomcategorymotion-devices httpcataloge-jpccom httprepair-searchschneiderelectricrepaircomcategoryby-product-type httpservolinearcomthomasnet-navigatorcomproductservo-drive-componentspositioning-controller httpmotionsystemspi-usaus httpbaldorthomasnetcom httpcatalogjamiesonequipmentcomcategoryrs-motor-controls-and-gear-reducers-motor-controls httpcataloge-jpccom httpboydelectricalstagethomasnet-navigatorcom httpcookindustrialthomasnetcomviewitemsindustrial-parts-vfd-s-inverters-cerus-invertersampbc=100|1025|1027 httpcatalogkofflercomcategoryvariable-frequency-drivesampbc=1007C1279 httpwwwgamainccomrc httpautovacthomasnet-navigatorcomcategoryadvanced-motor-controls-software httpdc-drives-motorsgrahammotorsandcontrolscomcategorydc-motor-controllers httpbodineelethomasnetcom httpproductsfifepearcecomcategoryproduct-catalog httpspindle-catalogtdmusaspindlescomcategoryhigh-speed-motor-drives httpcatalogpowertechcontrolscomcategorys-abb-control-abb-drives-abb-low-voltage-ac-drives httppumpsrapidservicecomcategoryyaskawa-vfd-drives