What does the letters and numbers of generator protection rating do mean?

What does IP21, IP22, IP23, the IP and numbers do? Below our company's technical engineer explained in detail:

IP (INGRESS Protection) protection rating system is drafted by IEC (International Electrotechnical Comms]). The electrical appliance is graded according to the characteristics of its dust-proof moisture. The IP protection level is composed of two numbers. The first number represents the device is off, prevents the ingredients of the external object, indicating the degree of the equipment moisturizing gas, waterproof invasion, and the number, the value of its protection level. The higher it.
The meaning of the first number:
0: No protection, no special protection
1: Solids greater than 50 mm can prevent solid foreign matter having a diameter greater than 50 mm into the shell. It is possible to prevent a large area of the body from accidentally or unexpectedly touching the inner charges or moving parts, but it is not possible to prevent consciousness.
2: Solid protection is greater than 12 mm, which prevents solid foreign matter having a diameter greater than 12 mm into the shell. Can prevent fingers from touching or moving in the shell 1
3: Solid protection is greater than 2.5 mm, prevent solid foreign matter having a diameter greater than 2.5 mm into the shell. Can prevent thickness or a tool, metal wire, etc., etc., metal wire, etc., etc.
4: The protective body is more than 1 mm, which prevents solid foreign matter having a diameter greater than 1 mm into the shell. Can prevent diameter or thickness of more than 1 mm wire or strip to touch the inner charge or operation of the case
5: Dust, prevent dust from entering the extent that affects the normal operation of the product, completely preventing the in-shells in the shells or moving parts.
6: Dust secret, can completely prevent dust from entering the shell, completely preventing the in-shell charging or moving portion
The meaning of the second number:
0: No protection, no special protection
1: Dripping, vertical drip should not be directly enteredgeneratorinternal
2:15 degree anti-drop, the drip within the 15 degree angle of the lead, should not be directly entered into the generator
3: Anti-watery, lys in the range of 60 degrees in the range of lead, should not directly enter the interior of the generator
4: Splash, splashing water in any direction on generator should have no harmful
5: Spray water, water spray in any direction on generator should have no harmful
6: anti-sea or strong water spray, violent waves or strong sprinkle on generator should have no harmful effects
7: immerse water,generatorImmersed in the water at the specified pressure and time, the amount of water injection should have no harmful effects
8: Diving, generator is immersed in water for a long time in the prescribed pressure, and its water supply should have no harmful effects.
The most common protection level in generator applications has IP11, IP21, IP22, IP23, IP44, IP54, IP55, etc.