Feedback power regulator. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Clocks, timers, relays, load switches
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It is often necessary to reduce the speed of an electric drill or other power tool with an AC commutator motor. In most cases, power controllers control the active load well, while the regulation of the reactive load has its own characteristics. Usually, either the number-pulse or the phase-pulse principle of regulation is used.
These issues are quite fully reflected in publications of different years, for example, in [1...3].
The proposed scheme provides current feedback control of the AC collector motor, due to which, with an increase in load, the torque on the shaft increases accordingly. The scheme was implemented to drive a sewing machine in a production environment. To regulate the speed of sewing machines, coal (tablet) rheostats are used, which are very short-lived. The regulator shown in the figure consists of a power switch on a trinistor VS1, rectifier valves VD1, VD2 and a variable resistor R2 in the control circuit. A rectifier bridge is provided at the output. All elements of the regulator are mounted on the board by surface mounting and covered with a shockproof case. Overheating of the trinistor was not observed, so it is installed on a mounting rack without a heat sink.
Some difficulty is presented by the mechanical assembly that transmits the force from the pedal to the axis of the potentiometer, but this can be overcome if a gear sector and a gear are used.
A characteristic feature of the regulator is its load feedback. As the load increases, the torque on the motor shaft increases. Thanks to this, the machine easily passes thickenings in the form of seams, it works more smoothly. Sparking on the collector was not observed.
When using a regulator for more powerful engines, it is necessary to select a rectifier bridge for current and install a trinistor on a radiator.
Literature
- Bastanov V.G. 300 practical advice. - 1989.
- Radio.- 1990.- №1.
- Radio amateur. - 1996. - No. 12.
Author: I.Semenov, Moscow region, Dubna; Publication: N. Bolshakov, rf.atnn.ru
See other articles Section Clocks, timers, relays, load switches.
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Comments on the article:
Michael
Well thank you.
kkbkinfo5site
Thank you so much!
Eugene
Collected, works. The variable resistor is needed only wire.
Ivanov E.I.
What's the point of putting a bridge at the exit? There and so only one half-cycle is positive. If we put it, then at the entrance, in order to use both half-cycles.
a guest
There are six extra diodes in the circuit.
Michael
There are no low speeds, which is bad for sewing.
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