FAQ VFDs Blog - Page 4 of 6

Eaton VFD Troubleshooting

March 10, 2014/in FAQ VFDs, Field Experiences, Industrial/by Ryan Chamberlin

Eaton VFD troubleshooting begins with technicians working with the VFD in production. Eaton VFD troubleshooting can be time consuming, so manufacturers tend to keep spare Eaton drives on hand for production lines that cannot afford downtime.When Eaton VFD troubleshooting cannot be resolved in the plant, technicians in the field are known to send their Eaton VFD to the original equipment manufacturer or Eaton VFD repair centers for repair and replacement options. The original equipment manufacturer of Eaton drives and Eaton VFD repair centers usually only offer a replacement for failed drives, but this isn’t usually the most economical solution for manufacturers.

Eaton VFD troubleshooting and VFD repair centers are an asset to manufacturers who use Eaton drive products, and Precision Electric is the best source for Eaton VFD troubleshooting and Eaton VFD repair.Precision Electric has been performing Eaton VFD Troubleshooting and Eaton VFD Repair since 1983.Precision Electric has helped save manufacturers thousands of dollars by repairing their failed Eaton VFD drives in lieu of of replacing Eaton VFD drives.

When Eaton VFD troubleshooting leads to Eaton VFD repair, the repair process should be taken with extreme caution. Eaton VFD repair should only be performed by technicians who have required training and experience to work with electrical equipment. Precision Electric strongly recommends to consult an expert in the field when repairing and troubleshooting Eaton VFD equipment.

The troubleshooting techniques for each brand of VFD can be unique, but the overall structure of troubleshooting always remains the same.The ultimate goal when performing Eaton VFD troubleshooting is to diagnose, repair and re-commission the unit as quickly as possible, and these are the steps that Precision Electric follows before anydis-assembly takes place.

1. Take Notes –Eaton VFD Troubleshooting

This is often a subject that is passed by many individuals who are attempting to troubleshoot industrial electrical equipment. Before Precision Electric begins to perform Eaton VFD troubleshooting, qualified technicians take note of many important aspects of the equipment including, but not limited to:

Eaton VFD Model Number
VFD Serial Number
Reason for Service
Urgency (Rush Overtime or Standard)
Visual Inspection of External Device

2.Diode and IGBT Tests –Eaton VFD Troubleshooting

When Eaton VFD Troubleshooting exceeds parameter changes, Precision Electric tests the input and output power sections of the Eaton VFD. This step is essential prior to applying power to the VFD unit. If for any reason there is a short on the input side or output side of the VFD, further damage can be caused to the unit if power is applied to it.

For this reason, Precision Electric uses meters to properly test the input and output power sections of the Eaton VFD prior to applying power to the actual unit. If a short is found, the unit can be disassembled and the cause of the short can be diagnosed and quoted for repair. If the repair is too costly, then a replacement is offered to the customer.

3. Power Up –Eaton VFD Troubleshooting

If the input and output power sections test healthy during this step of the Eaton VFD troubleshooting and repair process, Precision Electric will power up the unit and perform amp reading and output frequency tests. Precision Electric prefers to slowly increase power voltage to the unit until the rated input voltage of the VFD is achieved.

Depending on whether or not the VFD provides a display will determine what further action(s) will be taken. If display is unavailable, dis-assembly and diagnosis of the internal power supply of the control section of the VFD is likely necessary to further evaluate cause of failure and establish cost and lead time for the Eaton VFD repair.

4. Run A Motor – Eaton VFD Troubleshooting

If the previous three tests have passed during the Eaton VFD troubleshooting and repair process, then it is time to run a basic jog function of the VFD with a simple template program. Often when a VFD comes into our facility, we make sure to backup whatever program is currently stored in the VFD prior to inputting a template program and running a test procedure. This is to ensure we have a backup copy of the program.

The best method for backing up depends on the brand of drive, but after it has been backed up, we either reset the Eaton VFD to factory defaults through the keypad and recommission a basic start, stop and job application or closed loop if an encoder is involved. If the motor will not run, it will be necessary to check the output voltages and current ratings going to the motor to see if the VFD is functioning properly to rotate the motor.

5. Contact Customer – Eaton VFD Troubleshooting

At this point we have determined the cause of failure, estimated lead time and cost of the Eaton VFD troubleshooting and VFD repair. If the VFD has tested good entirely, then further underlying issues are communicated with the customer. This is when Precision Electricwill gather application specific information from the customer to establish whether or not it may be some outside issue associated with the system including, but not limited to, PLC communications, faulty IO, bad wiring or even bad cabling. There is no single way to do this step, as it depends on a wide variety of variables.

6. Send Service Tech – Eaton VFD Troubleshooting

If the customer cannot establish failure on any other aspect of the machine and the Eaton VFD troubleshooting tests appear to be good, then it may be necessary to send a Precision Electric field service technician on site to establish cause of failure. Precision Electricfield service technicians are trained to troubleshoot any issue ranging from standard VFD repair to advanced robotics, servo systems, electric motor issues and more. Precision Electric field technicians are trained to establish cause of failure and come up with solutions as quick as possible.

To learn more about Eaton VFD Troubleshooting or for Eaton VFD Repair Quotes, contactPrecision Electric, Inc.

VFD Manufacturers

February 18, 2014/in FAQ VFDs/by Ryan Chamberlin

When choosing VFD manufacturers for motor speed control equipment in production, it is recommended by Precision Electric to choose VFD manufacturers who offer extensive technical support for their products.Precision Electric recommends using VFD manufacturers in the United States, such asABBorLenze Americas. VFD manufacturers in the United States such as ABB and Lenze Americas have a reputable past for providing extensive technical support and troubleshooting for their VFD products.

USA VFD Manufacturers – ABB Low Voltage Drives

ABBlow voltage AC and DC VFD products are manufactured in the United States and are used across all industries and applications.ABBVFD products offer application specific functionality control for different types of motors as well as flexible connectivity to automation networks. ABB VFD products, inverters and converters are proven and reliable solutions backed by global production and life cycle services.

ABB VFD products provide scalable motor control from standard to demanding applications for a wide range of industries, especially in the process industries such as pulp and paper, metals, mining, cement, power, chemical, oil, gas, and more.

ABB VFD products are packed with advanced drive technology developed by ABB engineers and are capable of tackling even the most demanding requirements. A wide voltage and power range with various drive configurations and options enable one drive platform to be used for all needs.Precision Electric works closely with VFD manufacturers such as ABB.

Precision Electric offers retrofit solutions with the integration ofABBlow voltage VFD products to increase production time, and to increase energy efficiency for manufacturers across the nation. Precision Electric also offers ABB low voltage VFD distribution, technical telephone support, repair services and certified ABB VFD start up solutions. The ABB VFD Certified Start Up adds an extra one year warranty to anyABBVFDproduct that is installed by qualified Precision Electric service technicians.

USA VFD Manufacturers – Lenze Americas

Lenze AmericasVFD products are manufactured and stocked in the United States.Lenze AmericasVFD and automation technology is used in a wide variety of industries; including materials handling, packaging industry, robotics and automotive. Lenze Americas products are carefully coordinated and matched, and can be combined as required to provide the right solution for production needs. Lenze Americas automation solutions with integrated software and system engineering, and a global customer service, makes Lenze Americas a leader in their industry.

Lenze Americas reliability combined with the quality of their products and services consequently increases the productivity of industrial manufacturing. Precision Electric has been working with Lenze Americas for over 25 years. Precision Electric offers Lenze VFD retrofit solutions to industrial manufacturers to increase energy efficiency and production for manufacturers across the nation. Precision Electric offers Lenze VFD repair services, distribution, and technical support forLenze Americasproducts.

Precision Electric aims to increase production time, while maximizing energy efficiency to manufacturers across the nation.ContactPrecision Electric today for free VFD Repair or VFD Replacement Quotes.

Shipping A VFD

February 6, 2014/in FAQ VFDs/by Ryan Chamberlin

Shipping a VFD (variable frequency drive) safely is important because electronic components can be easily damaged due to poor packaging. When shipping a VFD, the first step to safely package the VFD is to locate an appropriatesize box for everything you intend to ship. When using larger boxes, keep in mind this will mean higher shipping fees from the carrier, and large boxes are unnecessary if you’re shipping small items.

When shipping a VFD, always either use a box supplied by the VFD manufacturer, specifically designed for the VFD, or a cardboard box with thick sidewalls that will not break during shipment.Once an appropriate box has been located, gently place the items in the box and use plenty of packaging materials within the box to keep the VFD safe during shipment. You can use Styrofoam, newspaper, bubble wrap, or any other type of shipping material that will keep the VFD protected within the box during shipment.Once the variable speed drive has been safely boxed up, seal the box with clear shipping tape. Masking tape and duct tape are not recommended and will not be accepted by most shipping carriers. Clear packaging tape is easy to find and holds cardboard better.

Precision Electric receives VFD Drives that are damaged during shipping nearly every day, but for the most part, VFD Drive users are aware that it’s important to package equipment safely when shipping a VFD, no matter how far of a distance the drive will be shipping. Call Precision Electric for VFD Drive repair quotes or variable speed drive replacement quotes.

Benefits of Using a Variable Speed Drive

January 23, 2014/in FAQ VFDs/by Ryan Chamberlin

Approximately one third of the world’s electrical energy is supplied by electric motors in fixed-speed centrifugal pump, fan, and air compressor applications. This proves thatsignificant energy efficiency improvement opportunities are available by applying variable speed drives to electric motors.

Variable speed drives have over the past decade allowed to become a cost efficient way to reduce energy costs and increase system production efficiency. Today variable speed drive manufacturers around the globe are finding more ways to benefit production processes by applying variable speed drives to manufacturing equipment .

Variable speed drives can reduce energy costs up to 50% by speed reduction on applications where the full speed (RPM) of the electric motor is not required.This energy savings is often significant enough to pay for the variable speed drive within a couple of months.

Variable Speed Drive Applications

Variable speed drives are used in many applications such as swimming pool pumps, air compressors, conveyor belts, lathes, mills, food processing production lines, waste water treatment pumps, HVAC fans and blowers, and many more applications in the industrial manufacturing world. Variable speed drivesare often used in manufacturing facilities to increase or decrease the acceleration and deceleration times on alternating current (AC) motors. Adjusting the acceleration and deceleration timeon an AC motor can add years to the lifespan of an AC motor, and can also improve efficiency on production demands. Variable speed drives can also provide the ability to be programmed to control the frequency of starting and stopping an AC motor.This ability provides a means by which an AC electric motor is only operating when needed for the equipment it’s rotating. AC electric motors have a longer lifespan if they are not continuously operating when they don’t need to be.

Variable speed drives have an average lifespan of up to about 8 years from fractional horsepower through about 10 horsepower, but larger horsepower drives have a longer lifespan which creates a market for manufacturers to use variable speed drive repair centers. Variable speed drive repair centers work closely with manufacturers to keep production at a maximum while reducing production downtime.To learn more about variable speed drives or for variable speed drive repair and replacement quotes, contact Precision Electric, Inc.

ABB Frequency Converters

December 3, 2013/in FAQ VFDs/by Ryan Chamberlin

ABB Frequency Converters are used to change the frequency and magnitude of the constant grid voltage to a variable load voltage. Frequency converters are especially used in variable frequency AC motor drives.

Figure 1 shows the behavior of an induction motor with several motor input voltages. The bold blue curve represents the electrical torque as a function of rotor speed when the motor is connected directly to a constant supply network. The blue portion of the torque curve shows the nominal load region (-1+1 [T/TN]), which is very steep, resulting in low slip and power losses. Similar motor torque behavior with other motor input frequencies can be achieved by feeding the induction motor with a frequency converter and keeping the ratio of the magnitude and frequency of the motor voltage constant. As a result, the shape of the torque curve remains unchanged below the nominal speed (constant-flux region -1+1 [n/nN]). In the field weakening region the motor voltage is at its maximum and kept constant, resulting in the torque curves being flattened.

Fig. 1. Operation principle of the frequency converter fed induction motor.

ABB Frequency converters can be classified according to their DC circuit structure to voltage-source (Fig. 4), current-source (Fig. 3) and direct converters (Fig. 2). With a voltage-source converter the variable frequency and magnitude output voltage is produced by pulse-width modulating (PWM) the fixed DC voltage, whereas with a current-source converter the output voltage is produced by modulating the fixed DC current. With a direct frequency converter the variable output voltage is formed directly by modulating the constant input voltage. At low voltage applications (<1000 V) the voltage-source topology is mainly used.

Fig. 2. Main circuit of the direct converter

Fig. 3 Main circuit of the current-source converter

Fig. 4 shows a typical voltage source frequency converter structure where a constant DC voltage is formed by using an input diode rectifier. The output voltage with variable frequency and magnitude is produced by pulse-width modulating the inverter bridge. In more sophisticated frequency converters the input diode bridge can be replaced with a PWM bridge enabling a higher DC voltage, reactive power control, nearly sinusoidal supply network currents and regenerative operation of the inverter.

Fig. 4. Main circuit of the commonly used voltage-source frequency converter.

Fig. 5a shows the operation of the inverter bridge with two different output voltages. The desired output voltage is achieved by changing the width and polarity of the output voltage pulses. The higher the instantaneous value of the output voltage, the wider the output voltage pulse needed. Although the output voltage contains a lot of high order harmonic voltages due to the PWM, the motor current is nearly
sinusoidal since the motor inductances filter out the high order current harmonics.

Fig. 5b shows the construction of negative voltage pulses, circled in Fig.5, during one PWM period. The graphic on the right shows the switching states of the phases and the resulting U-V voltage. The graphic on the left shows the space vector presentation of the eight switching states of the voltage-source converter. These switching vectors are commonly used to achieve PWM (vector modulation). The + and - signs mean that the phase is connected to the positive or negative rail of the DC link respectively.

Fig. 5a and 5b Operation of the voltage-source inverter with two different output voltage references and the principle of pulse width modulation.

To learn more about ABB Frequency Converters or to download technical information, visit the ABB Website.

Information References:

Types of Variable Frequency Drives

November 6, 2013/in FAQ VFDs/by Ryan Chamberlin

There are 3 general types of variable frequency drives:

Eddy Current Drives
DC Drives
AC Drives

Each type of variable frequency drive can be divided into different variations. Every variable frequency drive system operates an electric motor and a speed control unit. Variable frequency drive technology in today’s manufacturing processes mainly consist of solid state electronic components in a single control system. Older variable frequency drive systems use mechanical moving parts that in short periods of time, result in equipment failure due to worn parts from constant motion.

DC Motor Drives

DC motors have a rotating armature winding (winding in which a voltage is induced) but non-rotating armature magnetic field and a static field winding (winding that produce the main magnetic flux) or permanent magnet. Different connections of the field and armature winding provide different inherent speed/torque regulation characteristics. The speed of a DC motor can be controlled by changing the voltage applied to the armature or by changing the field current. The introduction of variable resistance in the armature circuit or field circuit allowed speed control. Modern DC motors are often controlled bypower electronicssystems called DC drives.

DC drives are also known as DC Motor Speed Control Systems.The speed of a DC motor is directly proportional to armature voltage and inversely proportional to motor flux; either armature voltage or field current can be used to control the motor speed. DC Motors have become expensive and today most DC motor speed control systems are retrofitted with an AC induction motor and AC variable speed drive. AC variable frequency drives are less expensive than DC Drive systems, are more available and are more energy efficient than DC Drive systems.

Eddy Current Motor Drives

An eddy currentdrive consists of a fixed speed motor and an eddy current clutch. The clutch contains a fixed speed rotor and an variable speed rotor separated by a small air gap. A direct current in a field coil produces a magnetic field that determines thetorquetransmitted from the input to the output rotor. The controller provides closed loop speed regulation by varying the clutch current, allowing the clutch to transmit enough torque to operate at the desired speed. Speed feedback is provided by an integral AC tachometer.

Eddy current drives are less efficient than all other types of variable frequency drives.Nearly all eddy current motor drive systems are obsolete today. Eddy Current motor drives were designed and manufactured decades ago and there are very few manufacturing facilities across the globe that still use them in production. When an Eddy Current motor drive system fails, it’s usually too expensive to repair and impossible to replace. When an Eddy Current motor drive reaches the end of its life cycle and can no longer be repaired, manufacturers retrofit the Eddy Current Drive system with an AC Induction Motor and an AC Variable Frequency Drive system.

AC Motor Drives

AC variable frequency drives are also known as, VSDs (variable speed drives), inverters, AFDs (adjustable speed drives), and micro drives. AC variable frequency drives are used in many applications such as AC Servo Systems, Air Compressors, Conveyor Systems, Lathes, Mills, Food Processing production lines, Waste Water treatment systems, Submersible Pumps, HVAC fans and blowers, and many more applications in the industrial manufacturing world.

Approximately one third of the world’s electrical energy is supplied by electric motors in fixed-speed centrifugal pump, fan, and air compressor applications. This proves thatsignificant energy efficiency improvement opportunities are available in the industrial manufacturing world if older DC motor speed control systems and eddy current drive systems are retrofitted with AC variable frequency drive systems.Most industrial manufacturers replace their eddy current and DC variable frequency drive systems with AC variable frequency drive systems. Today, technology has reduced AC variable frequency drive systems’ cost, physical size, and has improved performance through advances in semiconductor switching devices, simulation, control techniques, and control hardware and software.

Manufacturers across the globe capitalize on AC variable frequency drive technology to save money on their utility bills, increase quality control, decrease production downtime, and improve overall efficiency on production lines.

Information References:

What is a Variable Speed Drive?

May 8, 2013/in FAQ VFDs/by Ryan Chamberlin

Variable speed drives are also known as variable frequency drives, VFD’s, adjustable speed drives, and inverters. Variable speed drives are solid state motor control systems used mainly for industrial manufacturing. Variable speed drives are designed to control the speed of an electric motor. Variable speed drives can reduce energy costs up to 50% by speed reduction on applications where the full speed (RPM) of the electric motor is not required.

The energy saved on a utility bill from using a variable speed drive is often significant enough to pay for the variable speed drive within a couple of months from installation date. Variable speed drives are commonly used on pump, fan, and air compressor applications, and are often used in manufacturing facilities to increase or decrease the start up time on alternating current (AC) electric motors.

Increasing and/or decreasing the start up time on an AC current electric motor via a variable speed drive can add years to the motor’s overall lifespan. Using a variable speed drive can also improve efficiency on production demands. Variable speed drives provide the ability to control the frequency of starting and stopping an AC electric motor.This ability provides a means by which an AC electric motor is only operating when needed. AC electric motors have a longer lifespan if they are not continuously operating when they do not need to be.

Types of Variable Speed Drives

The most common type of variable speed drive is known as a V/Hz (volts per hertz), and are applied to applications such as fans, pumps, air compressors, and other related applications wherehigh starting torque is not required. V/Hz variable speed drive applications typically do not require full torque when the AC motor is operating at less than the base speed (RPM) of the electric motor. V/Hz variable speed drives are the most inexpensive type of variable speed drive. V/Hz variable speed drives do not provide full motor torque at low RPM.

Open-Loop vector drives are also known as s”ensorless vector” variable speed drives. Open loop vector drives adapted the name “sensorless vector” because they do not use an external encoder for speed feedback to the motor.Open loop vector drives are used in applications where high starting torque and full torque at low speed (RPM) is required. Open-Loop vector drives operating a motor a zero RPM should not be used on crane or hoist applications. Most open-loop vector drives are used on CNC machines, mixers, mills, lathes, and other applications where high starting torque or full torque at low RPM is needed.Open loop vector drives are usually more expensive than a V/Hz variable speed drives.

Closed-Loop vector drives are used in applications where precise speed control (0.01%) is needed, or in applications where extensive programming is needed. Closed-Loop vector drives use an encoder on the motor to provide constant shaft position indication to the drive’s microprocessor. The encoder feedback allows the drive microprocessor to constantly control torque no matter how many RPM the motor is operating at. Closed-Loop vector drives are used to provide the motor to operate at full torque even at zero RPM. Closed-Loop vector drives are commonly used on hoist and crane applications because crane and hoist motors must produce full torque prior to it’s brake being released, or the load will drop and it will not be able to stop.

Variable Frequency Drive Basics

June 28, 2012/in FAQ VFDs/by Ryan Chamberlin

Variable frequency drives are also known as (VFDs), variable speed drives (VSDs), adjustable speed drives, and inverters. Variable frequency drives are solid state controllers used in AC or DC electric motor applications. Most variable frequency drives are applied on alternating current (AC) electric motors in the industrial manufacturing world. There are some direct current (DC) electric motor applications that apply variable frequency drives, but most manufacturers seek AC motors because DC motors are expensive and often fail. Variable frequency drives can also be used as a phase converters when three phase motors need to be operated from single phase power.

Variable frequency drives can be used in small appliances, large mills, lathes, air compressors, conveyors, and many other electric motor applications in the industrial manufacturing world. Over 30 percent of the world’s electrical energy is consumed by electric motors in fixed-speed fan, pump, and air compressor applications. The basic idea for using a variable frequency drive on mills, air compressors, and fans is to reduce the amount of electrical energy being consumed which consequently reduces electricity costs on unused power.

Energy Savings

About 3% of the total installed AC electric motors in the United States use variable frequency drives.An estimated 60-65% of electrical energy in the United States is used to supply electric motors, and 75% of that electrical energy is consumed by fan, pump and air compressor applications.

Approximately 18% of the electrical energy used in the 40 million motors in the United States could save power consumption via efficient energy improvement by using variable frequency drives on these electric motor applications.

Performance and Operation

Variable frequency drives are applied to alternating current (AC) electric motors to increase quality control in manufacturing processes in the industrial manufacturing world. Variable frequency drives increase quality control in the industrial manufacturing world via monitoring the electric motors’ speed, pressure, temperature, torque, and tension.

Fixed-speed electric motor loads subject the electric motor to a high starting torque and electrical current surges that are up to eight times the full-load motor current. When a variable frequency drive is used on an electric motor, the variable frequency drive gradually ramps the electric motor up to full load operating speed, and this decreases mechanical and electrical stress, which minimizes motor maintenance and motor repair costs which ultimately, extends the life of the electric motor and manufacturing equipment.

Variable frequency drives’ unique programming capabilities allow for application specific patterns to minimize electrical and mechanical stress on the electric motors’ they’re operating. Every variable frequency drive manufacturer uses a unique parameter selection designed so that every manufacturing facility can seek out the product designed for their industry.

Repair and Replacement

The internet has brought high demand of quality repair processes and competitive pricing in the industrial manufacturing world.Maintenance technicians began seeking alternative solutions via the internet for their need of variable frequency drive repair and replacement because maintenance technicians do not always receive the services needed to be a leader in their industry.

A highly trained repair facility is the backbone of successful production. Precision Electric has been repairing industrial electronics, rewinding electric motors, and servicing all other industrial-related equipment since 1982. Customers on the coasts of the United States send Precision Electric repair work everyday such as variable frequency drives, servo motors, servo drives, encoders, printed circuit boards, electric motors, and all other related equipment.

Precision Electric offers free quotes for all repair work and has a reputation for keeping manufacturers’ downtime to an absolute minimum while increasing production processes for 30 years. Equipment repaired by Precision Electric is more reliable than brand new equipment purchased from the manufacturer, because Precision Electric uses the most advanced testing equipment and replaces generic components with the best components in the industry. Precision Electric offers an in-service warranty on all repair work completed. The Precision Electric in-service warranty begins the day repaired work is put into service and ends 12 months thereafter.

Types of Variable Speed Drives

June 11, 2012/in FAQ VFDs/by Ryan Chamberlin

There are three general types of variable speed drives- DC Motor drives, Eddy Current Drives, and AC Motor drives.Each type of variable speed drive can be divided into different variations. Every variable speed drive system will include an electric motor and a speed control unit. Variable speed drive technology today mainly consists of solid state electronic components in a single system. Older variable speed drive systems used mechanical parts that over time, resulted in failure due to moving and worn parts.