Variable-Speed Drive

variable-speed drive

[′ver·ē·ə·bəl ¦spēd ′drīv]
(mechanical engineering)
A mechanism transmitting motion from one shaft to another that allows the velocity ratio of the shafts to be varied continuously.

Variable-Speed Drive


a separate or built-in unit of a machine for the smooth alteration of the gear ratio. The drive consists of one or several infinitely variable transmissions and devices that ensure their operation. The basic characteristic of the variable-speed drive is the range of regulation—that is, a ratio of the largest gear ratio to the smallest (usually 3-6; less frequently 10-12).

Variable-speed drives provide optimal speed conditions of a machine under various operating conditions. For example, on a machine tool the best cutting speed for the various parts of a blank can be maintained when processing a rotating surface of varying radius. On subway escalators, variable-speed drives serve to closely match the speeds of the handrails and the stairs. These drives are used on machine tools, machines, and mechanisms of the textile, paper, and chemical industries, and in transportation. A widespread construction is a V-belt variable-speed drive with a built-in electric motor. The use of such drives as infinitely variable speed regulators (with programmed control when necessary) is rising significantly in connection with the possibility of using them for the automation of the control of production processes.


References in periodicals archive ?
Uses advanced controls and variable-speed drive to take advantage of 99% operating hours with off-design conditions.
ABB announced it is launching an advanced control package embedded within a variable-speed drive. Called SmartMill, it utilizes real-time data for continuous control of individual grinding mills, easing the burden on the operator's experience and judgment.
It is often said that using a variable-speed drive is the best way to save energy, no matter what the application.
A variable-speed drive converter also eliminates the current spikes generated during acceleration and torque surges, ensuring less wear on the mechanical system components.
* A combination of a variable-speed drive with an AC induction motor.
Each ICL unit consists of a centrifugal compressor, high-speed motor, transformer and variable-speed drive. The scope of the contract also covers spare parts, training and turnkey installation.
It's one part software; one part variable-speed drive.
Has variable-speed drive motor and can also be controlled and monitored using PolyLab monitoring software.
The left spindle features a new belt-driven cartridge-style gearless headstock featuring a high-torque 25hp or 35hp AC GE Fanuc spindle motor with a variable-speed drive. Two spindle options allow you to match the spindle speed and size to specific production needs.
Table speed is controlled in both fore and aft directions by an AC variable-speed drive with a minimum speed of 5 ft/min and maximum speed of 180 ft/min.
in New Berlin, Wis., has built a "swinging choke" for its ACS550 variable-speed drive to combat the harmonics that such drives produce in line-side, upstream circuits.
Stroke rate is easily automated using a variable-speed drive. A single ball check valve, standard on both suction and discharge side of the pump, provides accurate metering and fast response.

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