Motor Controller | Electronic Project Circuits

Posts Tagged ‘Motor controller’

AC Motor Speed Control by SCR

This circuit will allow you to control the speed of an AC motor, for example an electric drill. The way that this circuit works is as follows. The bridge rectifier produces dc voltage from the 120vac line. A portion on this current passes through the 10K ohm pot. The circuit comprised of the 10k pot, the two 100 ohm resistors and the 50uf capacitors delivers gate drive of the SCR. The diode D1 protects the circuit from reverse voltage spikes. The ratings of the bridge rectifier and the SCR should be 25 amps and PIV 600 volts. The diode D1 should be rated for 2 amps with PIV of 600 volts. The circuit can handle a load up to 10 amps. The SCR should be very well heat sinked.
If you want the convenience of creating this project.
Please looking to AC Motor Speed Control

Source:http://home.maine.rr.com/randylinscott/aug99.htm
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Be the first to comment - What do you think? Posted by admin - February 26, 2008 at 12:20 am

Categories: Electronic Control, Motor controller Tags: AC dimmer, Electronic Control, Motor controller

Controlling the speed of 3 phase induction motors

The speed of a normal 3-phase induction motor is a function of the frequency of the supply voltage. Changing the speed of such a motor hence requires building a 3-phase power frequency convertor. The driver can be realised using power mosfets (or IGTB’s) capable of handling high voltages and fast switching speeds. The generated frequency can be programmed in a small PIC controller and even in a fast Basic Stamp.

Note that at lower than normal frequencies, the voltage should be decreased proportionally. If you forget this, the motor may overheat and eventually even burn out. (See note at the bottom of this paragraph). The circuits shown here serve mere educational purposes (although they do work!) and are not always the most suitable nor safest sollution.

Read More Source:http://www.logosfoundation.org/kursus/2113.html
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Be the first to comment - What do you think? Posted by admin - February 25, 2008 at 9:13 am

Categories: Electronic Control, Motor controller Tags: Electronic Control, Motor controller

Fan Controller by 741

The amplifier gets quite hot while in use, so decided to use a fan to cool it. The fan, however, adds a lot of noise. To get the best of both worlds, I thought I’d turn the fan on only when required. The circuit shown uses two forward-biased diodes, one as a sensor diode (at JP2) and the other as a reference diode (D2). The small difference in forward voltage drop is amplified by IC1 and used to drive T1. T1 turns on a fan when the temperature on the reference diode exceeds that at D2. D1 prevents inductive kickback from killng T1. B1 and C2 provide a rectified, regulated supply from the transformer’s auxiliary 12V winding. This prevents noise from the fan motor getting coupled to the rest of the amp.
R1 is used to adjust the temperature cutoff point. This is done by first adjusting it to remain permanently off (turn it both ways, whichever way causes it to turn off, turn it all the way there). Now let the amp run for a while at a reasonably loud volume, so that the output devices heat up. Now place the reference diode on the heatsink of the output devices and back down R1 until the fan just turns on. Make sure that the fan is positioned such that after a while, it cools down the output devices enough to turn itself off.
This and the next circuit are built on the same board, and use the same auxiliary 12V supply, to avoid loading the 78L12 and to prevent fan noise from being coupled into the amp.

Source:http://wiredworld.tripod.com/tronics/mixer.html
Thank you.