Hi there!
It there seems to be a problem to get hold of a 220V AC Infrawave oven in Europe (looks like they are all designed for 110V AC / US). In case we plug in a 110V oven in a 220V socket it will be alot of smoke and that would be too bad for such a nice piece of equipment. So how about modifying the Black and Decker Infrawave oven for Europe use? In case it is possible to wire two of the infraread heaing elements in series, the total series resistance of the elements would double and the the voltage over each element would be half of 220V (220/2 = 110V). One of the elements will be a rough series “regulator” that dissipates a lot of energy (intentionally). The drop over each element should be the same and they will dissipate the same power as when wired in paralell.
Does somebody on this forum have the wiring diagram of the Black and Decker Infrawave oven? In case it uses four identical elements that are originally wired in paralell, and they can be rewired, I guess this could be a solution. Purchasing some ovens on E-bay and sending them via low cost shipment as a group buy isnt such a big deal.
The electronics inside the box would be discarded anyway and the blower etc would have to be taken care of separately.
Anyone with the schematic or even better that could have a look if the unit has paralell wired elements?
Another idea: what about using two of these Philips infrared heating elements with solid state control inside a conventional toaster oven chassis (in case the B&D oven is not at hand): http://uk.rs-online.com/web/search/sear … &R=0272306
Is it shortwave IR that is employed by Black and Decker in their Infrawave ovens ?
From Wikipedia (http://en.wikipedia.org/wiki/Infrared_heater):
"Efficiency of infrared heaters
Theoretically, the efficiency of an infrared heater is 100% as it converts nearly all electrical energy into heat in the filament. The filament then emits its heat by infrared radiation that is directly or via a reflector impinging on the product to be heated. Some energy is lost due to conduction or convection.
For practical applications, the efficiency of the infrared heater depends on matching the emitted wavelength and the absorption spectrum of the material to be heated.
For example, the absorption spectrum for water has its peak at around 3000 nm. This means that emission from medium-wave or carbon infrared heaters are much better absorbed by water and water-based coatings than NIR or short-wave infrared radiation.
The same is true for many plastics like PVC or polyethylene. Their peak absorption is around 3500 nm. On the other hand, some metals absorb only in the short-wave range and show a strong reflectivity in the medium and far infrared. This makes a careful selection of the right infrared heater type important for energy efficiency in the heating process."
Question to the reflow people on this forum: does this mean that shortwave IR should be used to effectively heat metals (pads, solder, bga solderballs, copper etc) instead of longwave infrared? Is that why the Black and Decker Infrawave is preffered to a traditional run of the mill toaster?
By looking at the Philips spec. sheet (click on the link above), it looks like the that IR heater has its spectral peak in the 2500nm range. That means this is shortwave IR. Phillips also have elements in the 2700, 2800 and 2950 nm range (more longwave elements) by the way.
Marius
