Need help understanding schematic

Thread Starter


Joined Nov 17, 2018
Hi, I'm a technician attempti g to get this machine running. I have the schematic, which typically i have no problem understanding .But i can't make sense of this one. Hopefully some one else can. Thank you in advance for any insights. I attached the schematic below, i realize there are no specs so hopefully i list all relevant details. The cutter in working on is:
single phase
contactor has 220v coil
Transformer 220>24
Key pad is 24 Vac
relay is 220
There are two motor:
one for rollers
One for cutting
Keypad locks machine out until code is entered

My confusion is the key pad appears to tie into the a2 and high side of contactor. I am wondering how this is possible considering it is a 24 volt keypad, hooked into the 220 power and not fry it. Perhaps I am missing something, can anybody assist or explain to me how this works



Joined Jul 18, 2013
It would appear the keypad would have a relay contact output.
Or possibly a small opto isolated Triac.
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