Does anyone know what the "Z" lying down symbol is that is in parallel with the normally closed relay contact CRB? I have searched several electrical symbol sites but no luck. The circuit is controlling 24 Vdc power for a motor brake. There is a back EMF arc when this contact opens so the symbol could represent a snubber which in this case may have failed. It will be this weekend before I can physically go in and look for this device. One other bit of info, this machine was built in Japan about 30 years ago.
I think that is a metal oxide varistor (MOV) or another TVS (Transient Voltage Supressor). Look at this symbol table.
The MOV symbol is near the middle of the table, with an image.