المولد متاح.

If المولد here means generator, the full MSA pronunciation is:

al-muwallidu mutāḥun
Arabic with vowels: المُوَلِّدُ مُتاحٌ

In normal pausal pronunciation, you will often hear:

al-muwallid mutāḥ

Two helpful notes:

• ال is pronounced al- here because م is a moon letter, so the l sound is pronounced clearly.
• The spelling المولد is ambiguous without vowels, so context tells you how to read it.

Because Arabic usually does not use a present-tense verb to be in sentences like this.

So:

• المولد متاح = literally the generator available
• Natural English translation = The generator is available

This is called a nominal sentence in Arabic.

If you wanted a past or future meaning, Arabic would use a verb, for example:

• كان المولد متاحًا = The generator was available
• سيكون المولد متاحًا = The generator will be available

Because متاح here is the predicate of the sentence, not an adjective directly modifying the noun.

In Arabic, the predicate of a nominal sentence is usually indefinite, even when the subject is definite.

So:

• المولد متاح = The generator is available

But if you want available to directly describe generator inside a noun phrase, then both words should be definite:

• المولد المتاح = the available generator

That is a very important difference:

• المولد متاح = a complete sentence
• المولد المتاح = a noun phrase, not a full sentence by itself

Yes. In this sentence, متاح functions like a predicate adjective: available.

More technically, it is also a common passive-participle-type form used adjectivally in Arabic. Learners do not need to analyze that every time, but it helps to know that Arabic often uses forms like this as adjectives.

Here it simply describes the state of المولد:

• المولد متاح = The generator is available

Yes. It agrees with المولد in gender and number.

Here:

• المولد is masculine singular
• so the predicate is متاح = masculine singular

Examples:

• المولدة متاحة = The generator/device is available if the noun is feminine
• المولدات متاحة = The generators are available

One subtle point:

• It agrees in gender and number
• but it does not need to match in definiteness here, because it is the predicate, not an attributive adjective

In fully vocalized MSA, the sentence is:

المُوَلِّدُ مُتاحٌ

Both words are in the nominative:

• المولدُ = the subject of the nominal sentence
• متاحٌ = the predicate

In everyday reading and speaking, final short vowels are often not pronounced in pause, so you will commonly hear:

المولد متاح

If you change the structure, the endings can change. For example:

• ليس المولد متاحًا = The generator is not available Here متاحًا becomes accusative after ليس.

Because Arabic is often written without short vowels, and that means one spelling can represent more than one word.

The spelling المولد could be read differently in different contexts. For example:

• المُوَلِّد = the generator
• المَوْلِد = the birth / birthplace / Mawlid

So the intended meaning and context tell you which reading is correct.

That is very common in Arabic, and learners get used to it over time.

Two common MSA options are:

• المولد غير متاح = The generator is unavailable / not available
• ليس المولد متاحًا = The generator is not available

A simple way to think about them:

• غير متاح is often the most straightforward way to say unavailable
• ليس ... متاحًا is a full verbal negation with ليس

Both are correct, and both are common in Modern Standard Arabic.