Yikes! A 254nm, 2-watt lamp at point blank range will erase most EPROMs in less than two minutes.
This is for those who can't count. You can easily recalculate power and time according to the datasheet of M27C512.
It is suitable if the emitted energy is 2 watts, not consumed.
Yes, I found it. For a UVC254 E17 3W lamp, 90 sec erasing has been tested in practice.
This lamp has a huge UV power - 160 mW! If the space around it is folded into 1 sq. cm, then the erasing time is 100 seconds.
I probably made a mistake when calculating the power before. Data for other lamps show that at a power of 4 W the radiation is ~100 µW.
Nevertheless, I believe that if there is a lamp, even if it is not suitable, but it erases UVPROM in 10 hours, then that is enough for me, I am not in a hurry.