Comparison Nowa W-3500 Professional vs Vega WH-450

The turn-on time of the filter in the chameleon mask (see "Type"), in other words, the time between striking the arc and darkening the filter to the operating level.

From a safety point of view, the turn-on time should be as short as possible: the faster the "chameleon" works, the less bright light from the arc enters the welder's eyes. On the other hand, reducing the reaction time affects the cost of the product. So for relatively small volumes of work, it is quite acceptable to use relatively “slow” masks — for 100 μs or more(especially since even in the simplest models, the reaction time does not exceed 1200 μs, while theoretically the maximum allowable value is 2000 μs). But for more serious use, you should pay attention to more "fast" options; nowadays, you can find masks with response times from 75 to 100 µs, from 50 to 75 µs, and even less than 50 µs.

Class is a complex indicator that determines the overall quality of the light filter in a chameleon mask (see "Type"). The class is indicated by 4 numbers, each of which describes a specific optical parameter. So, the first number indicates the overall clarity and lack of distortion; the second is the degree of light scattering; third — uniformity of blackout (presence/absence of visible blackout spots); the fourth is the angular dependence (how much the filter brightens when the angle of view deviates from the perpendicular). In each case, the larger the number, the worse this parameter is. The perfect indicator is considered to be 1/1/1/1, but in fact it is very difficult to achieve an perfect angular dependence, and there is no need to. Therefore, an indicator of 1/1/1/2 is considered quite sufficient even for a high-end professional filter.

The size of the transparent part of the light filter — the "working window", the area through which the welder sees the place of work. A larger working window provides ease of use and a wide field of view, but it significantly affects the cost of the mask and somewhat reduces the strength of the light filter.

The ability to change the sensitivity of the sensors responsible for the operation of the light filter in the "chameleon". Thanks to this function, you can adjust the filter in such a way that it is guaranteed to turn on from the arc and at the same time does not react to extraneous light sources. sensitivity adjustment is especially useful when there is numerous extraneous "flare" (for example, when several welders work close to each other, in bright sunlight, etc.).

The ability to manually set the delay time between the disappearance of the arc and turning off the filter in the chameleon mask. Such a delay is highly desirable in the light of the fact that even after the arc is turned off, the heated metal continues to glow for some time; therefore, it is advisable not to turn off the filter immediately. Adjusting the delay time allows the welder to independently choose the time to return to the non-working (maximally transparent) state.

A special mode of operation of the chameleon mask, in which the light filter sensors are completely turned off — thus, it constantly remains transparent and does not respond to any flashes. This mode is useful for jobs that can produce fairly bright flashes of light, but do not require dimming. A classic example of such work is grinding with a “grinder” or a machine tool, when sparks can fly from the workpiece; hence the name of this function — "grinding" mode.

— Backlight. Illumination system built right into the mask. This feature is very convenient when working in low light conditions: the backlight does not take up the hands (unlike hand-held flashlights) and does not create problems with wearing a mask (unlike headlamps), while the beam of light is always directed to where the welder's head is turned. On the other hand, such a system requires its own power supply. Therefore, it is used only in "chameleons", while the operation of the backlight additionally consumes battery power.