Power Quality and Drives LLC

Site Map for Powerqualityanddrives.com

Ac Drives

AC Drives by Cerus Industrial
AC Drives are available up to 1500 HP.

A Cogging Dc Motor

A Cogging DC Motor.
Probable causes of DC motor cogging are presented.

Books 1

Analysis of Electric Machinery and Drive Systems, 2nd Edition
Drive Systems Analyzed

Books 2

Faulted Power Systems Analyzed
Analysis of Faulted Power Systems by Paul Anderson

Books 3

Cable Systems for High Voltage and Extra High Voltage
Cable for High and Extra-High Voltage: Development, Manufacture, Testing, Installation and Operation of Cables and their Accessories

Books 4

Electrical Insulation for rotors and stators
Electrical Insulation for Rotating Machines: Design, Evaluation, Aging, Testing, and Repair

Books 5

Power Quality Problems, a book published by Wiley
Understanding Power Quality Problems: Voltage Sags and Interruptions

Books 6

Handbook of Electrical Engineering: For Practitioners in the Oil, Gas and Petrochemical Industry
Power system design within the oil, gas, petrochemical and offshore industries.

Books 7

Fluid Mechanics
The Fundamentals of Fluid Mechanics are examined

Books 8

IEEE Publications
Articles published by IEEE are available.

Consulting Services

Consulting and Training Services offered by Power Quality and Drives LLC
Power Quality and Drives LLC offers Training Seminars and Consulting Service

Contact Us

Contact Power Quality and Drives LLC.
Contact us for all your motor control needs.

Dc Motors And Drives

DC Drives and Motors .25 to 2 HP
DC Motors and Drives

Dc Motor Construction

High School Science Project: DC Motor Construction
Basic Construction of a DC Motor


Definitions of terms found in motor control.
Terms commonly used with motor control.

Emi Rfi

AC Drives and EMI/RFI Mitigation
EMI/RFI filters,line reactors, insulated power cable, proper grounding, all contribute to the reduction of EMI/RFI that is generated by variable frequency drives.

Emi Rfi Magnetic Resonance

EMI/RFI and Magnetic Resonance Imaging
EMI/RFI generated by variable frequency drives in a medical facility was causing an MRI machine to give false readings.

Emi Rfi Solutions

EMI/RFI Solutions
Solutions to EMI/RFI problems caused by variable frequency drives are presented.

Energy Savings Pump Vfd Part 1

Elusive Energy Savings: Centrifugal Pumps and Variable Frequency Drives - Part I
Calulating energy savings with variable frequency drives using the pump manufacturer's curves.

Energy Savings Pump Vfd Part 2

Elusive Energy Savings: Centrifugal Pumps and Variable Speed Drives - Part II
The Quadratic Equation is applied to Head vs. GPM pump curves for calculating energy savings.

Energy Savings Starters Vfds

Energy Savings: Solid-State Reduced Voltage Starters vs. VFDs
Two applications in which a reduced voltage starter may give better performance than a variable frequency drive.

Fuses Failed

Fuses failed to give protection a variable frequency drive
Fast-acting fuses can fail to protect variable frequency drives

Fuse Protection

Fast Acting RK1 vs. Semiconductor Fuses
Use of a Class RK1 fuse will give adequate protection to a variable frequency drive. Installation cost will be less than with semiconductor fuses.

Generators Standby Cogeneration

Generators: Standby and Cogeneration
Problems encountered by running motors and drives from generator power are discussed.

Golf Course Irrigation

Golf Course Irrigation
High Pressure Shutdown, Low Pressure Start with Golf Course Irrigation

Harmonic Reduction Calculation

Harmonic Reduction Calculation when using Line Reactors
Measuring Harmonic Orders on an existing system will aid in selecting an appropriate reactor.

Home Page

Variable Frequency Drives and Applications.
Variable Frequency Drives and the problems they create.

Line Reactors Emi Rfi

Positioning of EMI/RFI Filters, Line Reactors, Surge Suppressors and Fuses
General positioning of EMI/RFI filters and line reactors is discussed.

Motor Control

Motor Control Products Available
A variety of control equipment is available for electric motors

Motor Controls

Electric Motor Starters by Cerus Industrial
Nema Rated Starters for Electric Motor Control

Motor Control Burnout

Simultaneous Burnouts: Motor and Control
Protection to prevent both motor and control from burning out simultaneously.

Motor Protection

Electric Motor Protection
Motor Protection by Overload Relays

Overloaded Dough Mixer

Overloaded Dough Mixer
An overloaded dough mixer application is analysed for possible causes of the overload.

Overloaded Vfd Harmonic Current

An Overloaded Variable Frequency Drive Due to Harmonic Current Generation
The additional six percent increase in motor amps due to variable frequency drive generation may cause the motor amperage to exceed both motor full load amps and drive capacity, causing the drive to be overloaded.

Payback Analysis Vfd

Variable Frequency Drives and Energy Savings Payback Analysis
Monetary payback for energy savings achieved by the application of variable frequency drives on variable torque loads is analysed.

Privacy Policy

Privacy Policy
Our privacy policy is given here.

Pump Cavitation

Causes of Pump Cavitation
A problem with pump cavitation is presented.

Pump Control And Protection

Pump Control and Protection
Protection of pumps with electrical control is presented

Reduced Voltage Starting Torque

Solid State Reduced Voltage Starters and Starting Torque
Starting torque developed with the use of a reduced voltage starter must always be evaluated by considering the starting torque requirement of the load.

Sag Correction Without Ups

Voltage Sag Correction for Small Equipment Without Using UPS Systems
Various Techniques for Voltage Sag Correction are given here.

Seminar Problems Encountered

Variable Frequency Drives: Problems Encountered and Basic Mitigation Techniques
Mitigation techniques for problems caused by harmonics and emi/rfi are presented.

Short Circuit Transformer

Short Circuit Capacity: Basic Calculations and Transformer Sizing
Calculations for determining short circuit capacity and and transformer sizing is given here.

Skullduggery Afoot

Skullduggery Afoot!
Caveat Emptor!


Software, PCs and News
A variety of stuff that may be of interest.

Solid State Reduced Voltage

Reduced Voltage Starting Techniques
Advantages of Solid-State Reduced Voltage Starting Versus Across-the-Line, Auto-transformer and Wye-Delta Starting are given here.

Surge Suppressor Technology

Lightning Arrestor/Surge Suppressor Technology
Surge amps, clamping voltages and types of equipment protected by surge suppressors are discussed here.

Terms And Conditions Of Sale

Power Quality and Drives Terms and Conditions of Sale for Industrial Products
Terms and Conditions of Sale

Torque Constant Horsepower

Torque Capabilities of DC and AC Drives in the Constant Horsepower Range Using a Wound Rotor Motor Replacement as a Typical Application Example
Calculations for determining the proper torque and horsepower sizing is presented for AC and DC drives.

Transformers Tap Changing Regulator

Automatic Load Tap Changing and 3 Phase Regulator Transformers
Tap Changing and Regulating Transformers

Transients Disaster Averted

Transients: Disaster Averted by the Grace of God
Transient voltage surge suppression: An actual case history is analyzed to determine what should have been the proper protection against surges on a medium voltage power source.

Transients Equipment Malfunction

Transients: Equipment Malfunction
A variable frequency drive failed due to a transient generated by an equipment malfuction. The history of the failure is analyzed to determine what should have been the proper transient voltage surge suppression protection.

Transients Human Factor

Transients: Variable Frequency Drives and The Human Factor
Proper transient voltage surge suppression is analysed in an actual case history to determine what could have been used to prevent damage to two variable frequency drives.

Transients Lightning Strike

Transients: Lightning Strike
A lightning strike case history is analyzed to determine what should have been the proper transient voltage surge suppression protection.

Transients Power Disturbance

Transients: Incoming Power Disturbance
Effects of incoming power disturbances are discussed.

Transient Surge Protection

Transient Voltage Surge Protection
Various aspects of TVSS is discussed.

Tvss Energy Savings

Transient Voltage Surge Suppressors (TVSS) and Energy Savings?
Claims that transient voltage surge suppressors will cause energy savings are analyzed.

Us Government Agencies

Agencies for Energy Conservation, Science and Technologies
Websites for Science, Technologies and US Government Agencies

Variable Constant Torque

Variable vs Constant Torque Ratings
Most drives will have two ratings: one for variable torque and one for constant torque.

Vfd Nuisance Overload Trip

VFD with Nuisance Overload Trip
Possible solutions to overload trips

Vfd Ride Through Outage

Variable Frequency Drives Ride-Through On Power Outage
Motor Regeneration, Overhauling Loads, and Starting Into a Rotating Motor with Variable Frequency Drives

Vfd Ride Through Sag

Variable Frequency Drives Ride-Through On Voltage Sag and Outage
Methods of allowing variable frequency drives to ride-through during voltage sag.

Vfd Source Impedance

Variable Frequency Drives: Source Impedance and Line Reactors
AC Line Reactors are used to prevent damage to variable frequency drives by limiting inrush current caused by high short circuit capacity of the distribution system.

Vfd Speed Fluctuations

A Variable Frequency Drive and Speed Fluctuations
Possible causes of speed variances with a variable frequency drive were examined.

Wound Rotor Control

Wound Rotor Motor Replacement
Considerations for the proper replacement of a wound rotor motor are presented.

Wye Delta Starters

Wye Delta Reduced Voltage Starters
Starters offered incluse wye-delta.

Power Quality and Drives LLC
P.O. Box 83
Middlebury, CT  06762
Phone: (203) 217-2353
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