Energy efficiency has taken a quantum leap, aided by federal legislation, and the revolution continues as an evolution. The impetus behind this is the 30% waste of all energy generated.

Synchronous motors have gone digital, eliminating the effects of temperature variations, drift, and start-up tuning variations. From complete motors to retrofit kits, the technology is available in a wide range of motor sizes.

The AC flux vector drive is a hot development that gives an AC motor the high performance and high response of a DC motor while retaining its robustness and efficiencies. Consequently, the motor will have better dynamic performance, more predictable starting torque, less noise at low speeds, and fewer restrictions on application.

Motor testing by the manufacturer has gone from crude to high-tech and continues to advance. Some of the tools include CAE/CAD, automated testing equipment, three-dimensional graphic modeling, Finite Element Analysis, and material design analysis (magnetics, insulation, paints, varnishes, windings, laminations, coatings, etc.).

Manufacturers are optimizing winding and lamination designs, air gaps between the rotors and stators, ventilation systems, and rotor slot configurations. They are also using quality controls in the annealing process, all in an effort to bring losses down and efficiencies up. As a result, motors are continually getting better.

The introduction of adjustable AC motor drives to overhead cranes has given cranes more precise positioning capability, increased torque under load, and low maintenance. Replacing the contactors controlling an existing wound rotor motor (typically found on older cranes) will improve speed control and torque dramatically, even without spending the $2500 to $4000 to replace a functioning motor.

Brushless servo motors are now available in 2- and 3-in. frame sizes, in both NEMA and metric mountings, with UL and European compliance ratings. Some of these have the industry's highest torque per frame size, with a medium inertia design for improved load inertia matching.

Can't find a motor that fits your old production equipment? Dimension matching is here. Now, you can order a motor custom-built to exact dimensions, thus avoiding the need for an adapter base. This is appropriate in large motors with fabricated frames. In smaller cast motor applications, you can order a custom transition piece that makes aligning easy. Consider main conduit boxes when retrofitting: You can have these custom-built, as well.

Explosion proof motors now come in inverter-compatible configurations.

Almost all motors require motor-drive matching due to drive-induced corona effects and bearing currents. New technology allows design engineers to reduce both corona effect and bearing currents, lengthening the life of the motor. Drives have two other disadvantages: They take up space, and they send spikes through windings. Regarding the winding stress from those transients, some manufacturers now use special wire that is highly resistant to spike damage. One particular type of wire is 100 times more resistant to damage than standard wire.

It's now possible to get a motor with a matched drive incorporated into its housing, thus freeing up space formerly taken by a discrete panel and its mounting apparatus. Such a motor can be set up and operated with a locally mounted or remote keypad.

Category Ten


These items have appeared over the past year in EC&M's Product News section and received the highest reader response in their category.

High-performance drive

The compact, new ACS 300AC drive provides sophisticated control for AC motors ranging from 0.75 hp to 15 hp. Features easily programmable I/O configurations and serial communication interfaces that allow integration with higher-level automation systems or connection to various fieldbus protocols to enhance control capability. Includes, as standard, RFI filters that screen out electromagnetic disturbances, and is designed to conform to the new '96 EMC (Electro-Magnetic Compatibility) standards.

ABB Industrial Systems

Digital AC drive

The high horsepower CDE AC digital drive is a variable-speed drive (200 to 1000 hp) that features high performance and minimal harmonic interference. Can be operated as a standard V/Hz AC drive, or in open loop flux vector mode for improved speed and torque performance. Comes standard as a 6-pulse drive, and has been designed to easily incorporate a "zigzag" transformer with two 6-pulse rectifiers to configure a 12-pulse rectifier for reduced input harmonics.

Control Techniques Drives

Motor controller

The solid-state motor controller, the SMC Dialog Plus, builds upon the Smart Motor Controller (SMC) product line by adding advanced motor protection, power monitoring, and communication capabilities. The motor controller has a built-in programmable motor overload that saves panel space. Features include over/under current and voltage, jam, stall, phase reversal, and phase unbalance detection.


Inverter and vector motor controls

This broad range of 575V inverter and vector controls is now available. The Series 15H inverters, from 1 to 150 hp, are available for constant and variable torque applications. Series 18H vector controls are available from 1 to 150 hp and include the "Auto Tune" feature, which enables the control to adjust itself to a motor's performance. The 18H vectors provide full rated torque down to zero rpm and encoder feedback speed regulation of up to .001% of set speed.

Baldor Electric

Heavy-duty motor

The 841XL series of severe-duty AC motors offers reliability, energy efficiency, and performance. Designed and manufactured to meet or exceed IEEE 841 Standards, these motors provide an extra tough, long-life solution for severe-duty applications. Available in a wide range of ratings - from 1 1/2 through 500 hp and 200, 230, 460, or 575V. Features all cast iron construction to reduce vibration and ensure accurate mounting dimensions.

Reliance Electric

Motor drives

Now available is the 1336 Plus AC drive for 7.5 to 10-hp motors. The new version is 35% smaller than its predecessor. Third generation isolated bipolar transistor (IGBT) technology enables significant space reduction and matches the high functionality of this drive family. The newly packaged drive measures 13.78 in. high by 10.24 in. wide by 8.35 in. deep.


Category Ten


AC motor drives

The 1305 AC drive comes in preconfigured packages, combining control, communications, and power. The PWM inverter motor control for 0.5- to 3-hp applications at 230V, and 0.5 to 5 hp at 460V, provides energy-efficient operation. Flexible configuration eliminates mounting and interwiring of separate enclosures. Preprogrammed units are available in NEMA type 1, 4, or 12 enclosures.


Overload relay

The CR324X solid-state overload relay provides added motor protection where uptime is vital. Features include integral phase loss protection; solid-state surface mount technology; and selectable 10/20/30 trip class.

GE Electrical Distribution & Control

Elevator starter

The Series 72DP solid-state elevator starter is an alternative to the traditional electromechanical wye-delta starter. Requiring less maintenance, these starters allow for easy interchangeability with existing electromechanical wye-delta starters. The current limiting soft-start of the product reduces motor inrush during starting and provides smooth acceleration of the motor. Design also eliminates the contact wear and switching spikes.

Furnas Electric

Special-purpose AC drive

The GPD 505 adjustable-speed AC drive is a definite-purpose product intended to reduce system cost in applications that don't demand the maximum overload capacity or adaptability. The drive's software-based PID control eliminates separate cost. Since the drive is rated at 120% starting torque, the user doesn't pay for unnecessary overload ratings. Available in 5 to 200 hp, 230VAC, and 5 to 500 hp, 460VAC, and in NEMA 1 and 12 enclosures.


Pneumatic clutch

The FMCE is a totally enclosed, BISSC-certified, pneumatic clutch for installation in sterile environments. Accommodates all NEMA C-faced motors and reducers, frame sizes 56C, 143TC, and 145TC and operates with an axially traveling pressure plate engaging with a friction interface. Designed to be corrosion-resistant and splashproof.

Horton Mfg.

Motor controls

The Spectrum Motor Control Enclosures are UL-classified for Class I, Group B applications. The product line, which may be used with any manufacturers' control and/or circuit protection device, is also UL-classified for high AIC ratings in hazardous locations. Rated for 240V at 65,000A rms symmetrical; 480V at 50,000A rms symmetrical; and 600V at 25,000A rms symmetrical. For Class I, Div. 1, Groups B, C, and D.

Crouse-Hinds Div./Cooper Industries

Motor controls

The Contender Series of factory-sealed control stations and pilot lights is used in conjunction with contactor and magnetic starters for remote control of motors. Can be used in classified areas where flammable vapors, gases, or highly combustible dusts are present. Installed on standard, rigid conduit runs. Ratings are 10A, 600VAC.

Appleton Electric

Safety plug

The extension cord style SAF-Start-Plug, Models Nos. 1994 and 1995, are a low-cost solution to the OSHA and NEC requirement that machines cannot restart automatically after a power interruption. Rated at 120V, 15A.

JDS Products

Digital AC drive

The Unidrive digital AC drive incorporates standard V/Hz, open loop vector, closed loop vector, and AC servo technology. The control mode can be changed manually on the front panel or by using the firm's Windows-based configuration software. Available in ranges from 1 to 1000hp.

Control Techniques Drives

Multipurpose dynamic brake

This is a new microprocessor-based Multipurpose Dynamic Brake. Traditional DC injection brakes lack reliability due to welded contacts and blown fuses. This occurs when DC is applied before the residual AC voltage in the winding has dissipated. Permits braking only after the voltage in the motor reaches a safe level, thus eliminating a large current surge.

Baldor Electric

Inverter motor drive

The G3 inverter offers a drive system that can be handled by a standard, off-the-shelf, AC induction motor and the G3 inverter. Inverters offer high ampacity with a small mounting area, reliability with self protection, and a reduction in discrete components. The G3 inverter allows the standard AC induction motor to maintain a 0.1% speed regulation without an external tachometer or feedback device.

Toshiba International

Motor controller

The Spectrum EBM motor control enclosures (all sizes) are UL-classified for High AIC Ratings (UL Subject 2062) in hazardous locations. Rated to 240V, 65,000 rms symmetrical A, 480V 50,000 rms symmetrical A, and 600V 25,000 rms symmetrical A. Suitable for Class I, Groups C and D; Class II, Groups E, F and G; Class III; NEMA: 3, 3R, 4, 7CD, 9EFG, and 12 applications.

Crouse-Hinds Div./Cooper Industries

Motor monitor

The Model 423 Motor Load Monitor features monitoring of overload and underload conditions, while displaying the severity of the condition on a front panel-mounted analog meter. The analog meter can be used as an instant visual reference for the high and low setpoints. Usable over a wide range of motor voltages and horsepower ratings (typically from 0.5 hp to 100 hp).

Time Mark

Motor drive system

The MC Microdrive Series includes the following new models: 10, 15, 20, 25, and 30 hp at 480/590V and 7 1/2, 10, 15 hp at 230V. Other models included are 1/4, 1/2, 1, 2, 3, and 5 hp at 230VAC and 1, 2, 3, 5, and 7 1/2 hp at 460 and 575VAC. Several enclosure options are available. A C Technology

AC motor drive

The 1336 Impact AC drive is designed for 0.5 to 650 hp (0.37 to 485kW), stand-alone motor control applications. There is an AC vector control for single drive applications. Optional sensorless mode eliminates need for an encoder as a speed reference signal between motor and drive.

Allen-Bradley/Rockwell Automation

Motor drive system

The Universal AC Inverter combines four control methods in one compact drive, including both flux vector and conventional V/f control. For applications ranging from 3/4 hp to 500 hp, and available in both 230V and 460V.


Overload relay

The Model 777 Overload Relay is a fully programmable electronic device with RS 485 communications capabilities, ground fault protection, and a low price tag. Protects valuable machinery from damage due to overload, single phasing, high voltage, low voltage, and voltage unbalance.


Inverter-duty motor

The Black Max features high torque-to-inertia ratio, which enables its shaft to reverse direction, accelerate, and decelerate quickly with full torque. The motor is fitted with a high-performance winding that provides constant horsepower to twice its base speed. Available in 4-pole from 1/2 to 15 hp and in 6-pole from 1 to 10 hp.

Marathon Electric

VFD drive-compatible motors

The new line of motors, dubbed Speed Engineered and E-Plus Speed Engineered, prevents the destructive phenomenon called corona from occurring in the motor. Although most motors are designed to withstand corona when operated on line voltage, corona exists to a greater degree when operated from some inverters. Can also be modified to reduce bearing current.


Multimotor starter panels

The KTA3 Motor Circuit Controller can reduce multiple motor starter panel space by up to 60%. The KTA3 connection system reduces installation labor. The product is labeled for group motor installations in compliance with NEC Sec. 430-53.


Motor drives

ACH 500 AC drives with systems connectivity designed for the HVAC market provide motor control from 2 hp to 400 hp. Equipped with preprogrammed macros, including fan and pump applications, allowing configuration of I/Os and performance parameters.

ABB Industrial Systems

Modular design motor

The direct current thyristor motors, in IEC (metric) frames from 71 through 100, utilize a modular design. The basic round-body motor is provided with a universal end fitting that accepts B14 face or B5 flange mounts in IEC 71, 80, 90, 100, or 112 frame dimensions. Provisions for a bolt-on B3 foot mount.

Leeson Electric