Tesla Coils, High Voltage and Electronics
The ALTIVAR 58 (ATV58) family of adjustable frequency AC drive controllers is used for controlling three-phase asynchronous motors. This controller in from the range of: 1–75 hp (0.75–55 kW) constant torque (100 hp variable torque), 400/460 V, three-phase input. In …
Part 2: Teardown of the laser scanner module from a Fujifilm FCR XG-1 x-ray image scanner / digitizer. Also known as Computerized Radiography (CR), it fulfills the job of scanning a x-ray exposed image plate. It uses a laser beam …
I got hold of two electrical panels with a bad wiring job and the worst documentation. Not to say that it is completely out of code (racing fast for illegal). The did however turn out to contain a gem of …
Part 1: Teardown of a AGFA ADC 5155 x-ray image scanner / digitizer. Also known as Computerized Radiography (CR) it fulfills the job of scanning a x-ray exposed image plate. It is scanned with a laser beam and extract each …
I scavenged a old 4 ton stone polisher machine for the best components and got off with a 3 kW AC server motor + drive, 4+0.55 kW variable frequency drives. In this video I teardown the Yaskawa SGMGH-30DCA6F-OY 2900W AC …
I scavenged a old 4 ton stone polisher machine for the best components and got off with a 3 kW AC server motor + drive, 4+0.55 kW variable frequency drives. In this video I teardown the Fuji 7MBP50RA120 IGBT module …
I scavenged a old 4 ton stone polisher machine for the best components and got off with a 3 kW AC server motor + drive, 4+0.55 kW variable frequency drives. In this video I teardown the Yaskawa 3 kW AC …
I scavenged a old 4 ton stone polisher machine for the best components and got off with a 3 kW AC servo motor + drive, 4+0.55 kW variable frequency drives. In this video I try to make the servo motor …
The name means that the electrical polarity of the motor never changes. The axis of the rotating part of the motor is parallel to the magnetic field from the permanent magnet. Lorentz forces is what makes the motor turn, a conductor conducting current through a magnetic field will respond to a external magnetic field and will gain velocity in what direction the fields happen to be aligned. The hand rule applies here.
This motor is restricted to a single turn coil which limits it to small voltages around a couple of Volts and it has a low torque.
Homopolar generator
The homopolar motor will also work as a generator if we remove the battery and apply the motion to the rotating disc. It is only capable of supplying a couple of Volts but at very high currents, generators can be put in series for higher voltages. Very large homopolar generators are used for high current short circuit testing.
Warning: this motor operates at high speeds up to 6000 RPM, the screw can at any time loose contact and fly through the air.
Michael Faraday demonstrated this motor concept in 1821 at the Royal Institution in London. The homopolar motor is the first electrical motor to be built. His construction was a large and crude concept that he himself describes as “This apparatus may be much reduced in size, and made very much more delicate and sensible.”
The original article in Quarterly Journal of Science:
http://www.archive.org/stream/quarterlyjournal12jour#page/186/mode/2up
http://www.archive.org/stream/quarterlyjournal12jour#page/n485/mode/2up
You will need the following four items to make this experiment.
Follow these four steps to make it work.
A quick experiment that can be made from common household items. It is a simple practical demonstration of the basic electro magnetic theory, that would help many understand the force around a wire easier.
Published August 4, 2011. Updated October 31, 2021.
Published November 9, 2010. Updated June 19, 2021.
A coil winder is essential when it comes to making a beautiful coil on large forms.
It takes considerable less time to wind large coils and varnishing the coils while they are rotating gives a much better finish.
Control of speed and acceleration is key issues when building a coil winder.
The best choice is to get a Variable Frequency Drive meant for 3 phased asynchronous induction motors, especially if the motor have a gear.
With a VFD it is possible to control the speed with a potentiometer, control start and stop with a single push and hold button and control ramp up and down times.
Having both hands free to guide the wire onto the form is important
27th March 2010
With materials at hand the motor was secured to a horse with a custom drive wheel with a rubber band to get contact to the form. A gear is attached to the motor with the ratio of 1:14, this makes it possible to run the motor at higher speeds with the VFD. Running at speeds close to its native speed makes cooling more efficient as its self cooled from the rear fan.
The form is pressed against the roller wheels which keeps the form in place.
Controlling the winders motor is done with a Siemens Micromaster Vector 0.37kW VFD, a potentiometer is used to adjust the speed and a foot pedal is used for start / stop. The VFD is programmed with a slow start ramp to avoid breaking the copper wire.
The machine was built without buying any new materials and is quickly put aside as the rollers are hold to the horses with welding clamps.
Further improvements could be a turn counter and automatic wire guide, but with the relatively low number of large coils I make there is other fields I like to focus on.
A time lapse movie of me winding 0.25 mm wire on a 160 mm diameter form.
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