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 ?
The variable-speed drive is to consist of two clutches and a drive belt:
x 18-ft, variable-speed drive vibrating grizzly feeder.
Each ICL unit consists of a centrifugal compressor, high-speed motor, transformer and variable-speed drive.
It's one part software; one part variable-speed drive.
Larger downflow models are available with optional energy-efficient EC plug fans, while all versions are offered with optional variable-speed drive fans.
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.
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.
Stroke rate is easily automated using a variable-speed drive.
Virtually any part can be deburred, deflashed, burnished, polished, descaled or brightened automatically when the proper media and chemical compound are matched to the vibratory finisher, The machine features a variable-speed drive with vibration frequency from 1200-2600 cycles/min.
Options include weigh-scale hopper or cycle count control systems, adjustable side rails, discharge chutes, hoppers, photo eyes and variable-speed drive.
Siemens Industrial Solutions and Services Group (I&S) has received an order from MAN TURBO AG, Switzerland, to supply three variable-speed drive systems for the underground gas storage facilities in Aldbrough, Great Britain.

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