The heater of the four beer cans
The study of magnetic slow waves were developed some unusual devices. One of them is the heater on the aluminum battery with a capacity of 100W, and energy saving up to 30%. Its disadvantage is rather strong squeak emitted by the radiator and relatively expensive materials. In the following proposed design, these disadvantages do not exist: the battery used 4 cans of beer, and a specially developed pulse generator turned out to be incredibly simple and reliable. Despite the seeming simplicity of this heater gives good performance and just like its predecessor, saves up to 30% of electricity.
Its circuit diagram is depicted in the following figure. Her work is almost indistinguishable from the classic blocking-generator, but in contrast here the mode is selected in which the coil L1 occur slow magnetic waves. They, together with the magnetostrictive effect, and give the required economic parameters for the device. Resistor R1, together with the Zener diode ZD1 form a voltage offset for transitory VT1 and R2 — stabilizes the operation of the entire scheme, and helps her to come to a mode of resonance of the second kind. It will depend on the following parameters: - resistance VT1, the resistance R2, inductance L1 and capacitance C1. Coil L2 is also involved in this process, but its main task — the creation of a positive feedback.
Waveforms of voltage and current in coil L1 is presented here. The yellow graph is the voltage at the ends of this coil, the magnitude of which is denoted by Um, and the green current. The table below summarizes some of the dependency of supply voltage, power consumption from the power source and the amplitude of the voltage (Um) in the coil L1. Heat capacity is found by multiplying the column average by 1.3.
|The voltage, V (XS1)||Power consumption, W||The amplitude in the L1, In (Um)|
Experimenting with different mosfet-transistors, the author came to the conclusion that this scheme is best suited to those that have the lowest resistance of open transition. At the same time, maximum voltage, drain-source they should be at least 250V. Perfect — IRFP260. Capacitor C1 must be rated for a voltage below 600V and have good frequency characteristics. Well capacitors MKP10 or similar — from induction cookers.
The list of schema elements:
- VT1 — mosfet transistor IRFP260;
- ZD1 — Zener diode 1N4733;
- R1 — resistance at 0.5 watts. It can be replaced by two series-connected resistors 330ω and 0.25 W;
- R2 — resistance at 0.5 Ohm and 5W. Well suited ceramic resistor option, for example like this;
- XS1 — standard connector to the power supply at 12V, for example such.
Wire for L1 and L2: diameter 0.63 mm lacquer isolated copper. Coil L1 is wound on the four pre-glued together beer cans (see picture below) is almost at full height; optional turn to turn, but in a single layer. Banks in the middle, leave a small gap for winding 9-10 of the turns of the coil L2. All the winding are held in one (any) side. Although the surface of the beer is well insulated, but still it would be better between it and the wire to lay a layer of building paper.
Scheme is going on a small Board and is inserted between the cans in the middle. The transistor VT1 is mounted on a small heatsink.
The setting is in the proper phasing of the windings: if the enable generating circuit not, then you need to swap the terminals of winding L2. If the oscilloscope become between the common wire and the drain of VT1, it is possible to obtain such a waveform (yellow line). The current graph (green) is obtained if one of the terminals of the coil L1 to wear current transformer and connect an oscilloscope to its conclusions. Otherwise, the scheme finds the operating mode and does not require adjustment.
Another unusual indicator of proper operation can be measuring temperatures inside and outside the heater. Due to the induction nareva and the magnetostrictive effect, the temperature in the center should be slightly higher than on the outer surface of the cans. If the coil L1 is connected directly to the DC source, the situation will change: the external surface will be much hotter inside and that will cause the device to mode with the usual efficiency.