Tower Electric Motor Company - Three Phase Motor

TEMCo is a Motor Control Specialist Company You Can Trust - a Member of The Better Business Bureau. TEMCo  Is an Accredited Member of the Better Business Bureau.  Offering Stock and Motor Controls.

TEMCo is a Standard and Custom Electric Motor Supplier you can trust - a member of the Better Business Bureau.

Variable Frequency Drives

VFD Sales

Variable Frequency Drive Sale On Now! Call 1(510) 490-2187 For Sale Pricing
Lowest Prices on Variable Frequency Drives - Guaranteed!      Call 1-510-490-2187  or  1-800-613-2290

Baldor Motors Worldwide Electric Motors Leeson Motors Weg Motors US Motors Motor Prices AC Motors DC Motor Inverter Motor Variable Frequency Drives Three Phase Motors Magnetic Motor Starters Motor Control Power Factor Correction Electric Motor Home

Tower Electric Motor company sells a wide range of quality variable frequency drives at discount prices. We carry single phase and three phase, AC and DC VFDs. Whether your need is to control speed, torque, direction, breaking, motor slip compensation, multi-speed, etc., call TEMCo to choose the right variable frequency drive. If we don't have a stock variable frequency drive model available to meet your need we also do custom built VFDs. Quality Guaranteed.

Motor Products
Power Transformers
Three Phase Generators
Three Phase Converters


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Electric Motor Home
Your source for the widest selection of quality electric motor powered products at the lowest prices - guaranteed!
Rotary Phase Converters
Need 3 phase electricity and only have a 1 phase power source?  TEMCo is the most trusted manufacturer of Rotary 3 Phase Converters.

Rotary Converter Sizing Charts
Determine the size of phase converter that you need based on the amount of power you need for your 3 phase equipment.

Static Phase Converters
Read about this technology and what electric motor loads it can be used to start and when it is better to use a rotary phase converter instead.

Electrical Transformers
TEMCo has the broadest supply of electrical voltage transformers at the lowest prices - guaranteed!

Power Generators
We offer power generators for all applications from PTO generators to industrial diesel generators - you can rely on TEMCo as your power generator supplier

Three Phase Generators
With TEMCo's knowledgeable three phase specialists TEMCo can help you get the best model and best price on your three phase generator!

Order Electric Motor
Call our electric motor specialists today and place your electric motor order today.  Rest assured that you received the best motor product and the very best rates too!

Variable Frequency Drive Sales

Tower Electric Motor Company carries quality Variable Frequency Drives from Weg, Baldor, Leeson and many other quality brands. Our Variable Frequency Drives have a wide range of available controls, protective features and displays. TEMCo has a full range of motor controls and drives including variable frequency drives, soft starters, etc., to meet your motor starting, protection, and variable speed application needs.

Call (510)490-2187 for additional variable frequency drive details and to order.
Special sale on now!

Variable Frequency Drives

An overview of the development and application of Variable Frequency Drives.  

Several common applications that require speed control are conveyors, large pumps, boiler fans and many others.  In the past variable motor speed was achieved with several inefficient means such as wound rotor motors and variable rotor resistors.  The new more efficient and effective way to achieve this variable speed today is with variable frequency drives.

The speed at which and electric motor spins is directly relations to the frequency, phase and number of poles that and electric motor uses.  These three electrical factors do determine the speed of an electric motors rotating electric field.  In the US the standard frequency of most utility supplied ac power is 60Hz.  

By developing the technology to vary the frequency of the current supplied to special AC electric motors in modern time we have developed the much more efficient variable frequency drives

This technology became affordable to produce variable-speed drives which are now possible because of modern advances in solid-state electronics. A new product developed called an insulated gate bipolar transistor (IGBT) made it possible to switch large current levels at high-kHz rates, this lead to pulse-width-modulated (PWM) inverter drives. These units have relatively low distortion, are compact in form factor and have high operating efficiency.

Pulse-Width-Modulated-Inverters (PWM inverters) control the kHz-chopping rate of a wave; varying its envelope in voltage and fundamental frequency; to control the motor acceleration and running of the induction motor. The pulse rate can be set high enough to make audible noise of vibration, stimulated in the motor by the Variable Frequency Drive (VFD), inaudible. You can arrange the range of fundamental frequencies through which the drive accelerates and operates the electric motor to skip critical frequencies where resonance in the mechanical equipment and structural supports might be excited to levels that could cause damage.

The circuitry of a variable frequency is similar to other system applications of solid-state motor controllers and uninterruptible power supply systems, as used for large computer systems and data centers.

Variable Frequency Drive Categories

There are two general categories of Variable Frequency Drives (VFD) designs: Voltage source inverter (VSI) and Current source inverter (CSI.) Manufacturers of Variable Frequency Drives VFDs seemed to use one style or the other. The two types differ in the manner in which power is passed to the motor after being processed by the drive. The VSI drive treats the motor as a parallel-connected load and controls the overall performance envelope by adjustments to the output voltage of the drive. The CSI drive centers on motor impedance (inductive reactance) since it is driving current through the motor as part of the performance envelope. You must match CSI drives with their motors.

This motor matching is less important for VSI drives. Some use Variable Frequency Drives (VFDs) with motors of unknown origin, particularly in retrofits. However, one source should specify, purchase, and install Variable Frequency Drives (VFDs) with their associated motors whenever possible. Keep track of the thermal budget for the operating motor, and even for rooms housing large groups of drives.

For more variable frequency drive technical information call (510) 490-2187.

Tower Electric Motor Company has experience selling and maintaining variable frequency drives, electrical motors and manufacturing single to three phase converters over the years since 1968. All our electrical products are made to the highest quality standards and are backed by industry standard warrantees. When you want an electric motor, phase converter, power generator, or quality motor supply, turn to TEMCo.

Variable Frequency Drives - Order (510) 490-2187

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