The \ʌ\ in 'money' and 'mother' is the same. Your list is wrong - you have 'mother' in both parts. Here are some words which have the \ʌ\ vowel:
fun
sun
cup
son
come
love
done
The following words have \ʌ\ in the first syllable and a schwa \ə\ in the second syllable. This is because the first syllable is stressed while the second syllable is unstressed. We use \ə\ (a schwa) for unstressed syllables - it is shorter and weaker than the vowel in the first syllable:
London /lʌndən/
mother
other
cupboard
butter
As for the different pronunciations of 'some', this rule applies to any word which is sometimes stressed and sometimes not. For example, the preposition 'to' is /tu:/, but we only ever pronounce it in this way when it's stressed ( For example, "No. I didn't say I was travelling TO London - I said I was travelling FROM London!). In all other cases, 'to' is pronounced /tə/ because it's unstressed. For example, the sentence "Come to London" is pronounced / 'kʌm tə 'lʌndən/, with the two stressed syllable in their full form /kʌm/ and /lʌn/, and the two unstressed syllables reduced to schwas / tə/ and /dən/.
In your first sentence, "Some 80% of all residents took part in the vote", the word 'some' is stressed, so it has its full pronunciation - \sʌm\
In your second sentence, the word is unstressed, so it is reduced to \səm\. That's the only reason why the pronunciation is different. It's an issue of stress rather than meaning.
I hope this explanation was helpful to you.