Låsemekanismen åpnes når kodehjulet brukes.

Those endings mark the definite singular form, roughly the same as the in English.

• låsemekanisme = lock mechanism

• låsemekanismen = the lock mechanism

• kodehjul = code wheel
• kodehjulet = the code wheel

In Norwegian, the definite article is usually attached to the end of the noun instead of being a separate word.

• common gender singular often takes -en
• neuter singular often takes -et

So:

• låsemekanismen is a common-gender noun in the definite singular
• kodehjulet is a neuter noun in the definite singular

Because Norwegian usually puts the as a suffix on the noun.

So instead of saying something like the lock mechanism, Norwegian says låsemekanismen.

This is one of the biggest differences from English noun structure. The definiteness is built into the noun itself.

Norwegian makes compounds very freely, much more like German than like English.

So:

• kode = code
• hjul = wheel

Together they form kodehjul = code wheel

In English, we often write these as two words, but in Norwegian they are normally written as one word when they function as a single noun.

Also, the last part of the compound decides the gender and inflection:

• hjul is neuter
• therefore kodehjul is neuter
• definite singular: kodehjulet

The -s ending here marks the passive voice.

• åpne = to open

• åpnes = is opened / opens

• bruke = to use
• brukes = is used

So the sentence is describing what happens to the mechanism and the wheel, rather than focusing on a person doing the action.

This s-passive is very common in Norwegian, especially in:

• instructions
• technical descriptions
• formal or impersonal language

Yes. In fact, both verbs are passive:

• Låsemekanismen åpnes = The lock mechanism is opened
• når kodehjulet brukes = when the code wheel is used

That gives the whole sentence a technical, impersonal style, which is very common in manuals and descriptions of how things work.

Yes, it could.

These are two common ways to form the passive in Norwegian:

1. s-passive

   • åpnes
   • brukes

2. bli-passive

   • blir åpnet
   • blir brukt

So a similar sentence could be:

• Låsemekanismen blir åpnet når kodehjulet blir brukt.

But in technical or instructional language, the s-passive often sounds more natural and concise.

The dictionary forms are:

• å åpne = to open
• å bruke = to use

In the sentence, they appear as present passive forms:

• åpnes
• brukes

So if you look them up in a dictionary, search for åpne and bruke.

Når means when, and in sentences like this it often has the sense of whenever.

So:

• Låsemekanismen åpnes når kodehjulet brukes. = The lock mechanism opens / is opened when(ever) the code wheel is used.

This gives a general rule or repeated relationship: every time the code wheel is used, the lock mechanism opens.

Because når and hvis are not exactly the same.

• når = when / whenever
• hvis = if

In this sentence, når suggests a regular, expected result: using the code wheel leads to the mechanism opening.

If you used hvis, it would sound more like a condition that may or may not happen:

• Låsemekanismen åpnes hvis kodehjulet brukes. = The lock mechanism opens if the code wheel is used.

That is grammatically possible, but når is often more natural when describing how a device normally works.

Because Norwegian often uses the present tense to describe:

• general truths
• how machines work
• instructions
• regular processes

So even though English might sometimes use a more explanatory style, Norwegian simply uses present tense here:

• åpnes
• brukes

This is very normal in manuals and technical writing.

Because the sentence is talking about specific, identifiable parts of a device.

In technical descriptions, Norwegian often uses the definite form for parts and components that are understood from the context:

• låsemekanismen = the lock mechanism
• kodehjulet = the code wheel

Using the indefinite forms:

• en låsemekanisme
• et kodehjul

would sound more like you are introducing those items for the first time in a general way, rather than referring to the known parts of a particular system.

Literally, it is passive, so is opened is a close grammatical match.

However, in natural English, this kind of technical sentence is often translated more smoothly as opens:

• Låsemekanismen åpnes når kodehjulet brukes. = The lock mechanism opens when the code wheel is used.

So:

• grammatically: is opened
• naturally in English: often just opens

Both can be useful depending on whether you want a literal or natural translation.

Yes. You can move the når clause to the front:

• Når kodehjulet brukes, åpnes låsemekanismen.

This means the same thing.

A useful thing to notice:

• In the subordinate clause after når, Norwegian keeps normal subject-verb order:
  kodehjulet brukes
• In the main clause, if something else comes first, Norwegian uses V2 word order, so the verb comes before the subject:
  åpnes låsemekanismen

That is a very common Norwegian pattern.

Yes, absolutely.

This sentence sounds very typical of:

• instructions
• product descriptions
• engineering texts
• user manuals

The clues are:

• the use of definite nouns for machine parts
• the passive forms åpnes and brukes
• the general present tense
• the impersonal, factual style

So this is a very useful model sentence for understanding formal written Norwegian.