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Replacing a Mechanical Adjustable Speed Drive with a Variable Speed Drive

 

 
Retrofitting an application using a mechanical adjustable speed drive such as a Reeves Motodrive® to an AC or DC variable speed drive can be done successfully if all the details are understood beforehand. First, let's take a look at what a Motodrive really looks like conceptually. A constant speed motor is connected to a variable diameter sheave (item A in Figure 1) that transmits power through a belt to another variable diameter sheave (Item B). An internal gearbox can then be used to further reduce speed as necessary. The variable sheave/belt assembly will act as a reduction gear up to motor base speed, and then will increase speed beyond that. Sheave B speed will be the same as motor base speed when the diameter of the sheaves are equal, so motor base speed is roughly the midpoint of the speed range of sheave B.
Products & Services
Sheaves are grooved wheels or pulleys used with rope or chain to change the direction and point of application of pulling force. Learn more about Sheaves
Adjustable speed drives alter the speed of a driven shaft to a speed selected by an operator. Search by Specification | Learn more about Adjustable Speed Drives
V-belts and V-ribbed belts are power transmission drive belts with a triangular or trapezoidal cross section. They are available in a variety of belt materials, reinforcement styles, and speed configurations. Search by Specification | Learn more about V-belts and V-ribbed Belts
Material handling and pneumatic conveying blowers move air through an enclosed system to transport materials. They generate tremendous air flow in a tube (often by a vacuum) to pull granular materials, papers, powders, or pellets from one location to another. Search by Specification | Learn more about Material Handling and Pneumatic Conveying Blowers
Variable transmissions are used in industrial applications to alter the speed of an output shaft. Search by Specification | Learn more about Variable Transmissions
Product Announcements
Harrington Hoists, Inc. - Electric Chain Hoists
Harrington's (N)ER enhanced features three phase electric chain hoists are equipped with latest technology in the market today. All models include a low headroom, lightweight body with a fan-cooled... (read more)
Demag Cranes & Components - MPW - Multi Purpose Winch
Demag MPW Built Up Hoists are designed with standardized subassemblies thru 170 ton. Features such as Express Lifting provide efficient handling of your loads. Infinitely variable speed drives are... (read more)
Spectrum Instruments Ltd. - Sheave / Pulley Alignment: Model D160
The Easy-Laser D160 performs sheave / pulley alignment with digital precision. The D160 is magnetically attached in just seconds with the laser transmitter on one of the sheaves and the detector on... (read more)
David Round - Winches - wide selection
David Round is a leading supplier of high quality winch products, with many styles to choose from. (read more)
Alstom - Replacement Parts & Upgrades for Stock® Feeders
Over 2000 replacement parts for STOCK® coal feeders As the alternative OEM for STOCK Feeder parts, the Alstom/Merrick team is well positioned to support your need to improve performance,... (read more)
 
Topics of Interest
1 GENERAL The successful integration of electronic variable-speed drives into a system depends upon knowledge of a number of key characteristics of the application and the site where the system will... (Read More)
AC and DC motor variable-speed drive systems are the main projects of the power electronics . Energy storage in AC and DC motors has recently been investigated and discussed. AC motors can be... (Read More)
AC Motor - AC Motors may be operated at a constant speed, without variable speed control, or may be furnished with a variable frequency controller for variable speed control. Variable speed AC Motors... (Read More)
TYPES OF MOTORS Alternating-Current Motors SQUIRREL-CAGE INDUCTION MOTOR  By far the most common motor used to drive pumps is the squirrel-cage induction motor (Figure 1). This motor consists of... (Read More)
An induction motor can run only at its rated speed when it is connected directly to the main supply. However, many applications need variable speed operations. This is felt the most in applications... (Read More)
See more product announcements for Sheaves
Roller Sheave

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Hilman Rollers


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RUD Chain, Inc.


Knobs, Handles in Metal and Plastic

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