Is there a preferred rationale for naming constraints?

Is there a relevant name length maximum?

I was thinking about tagging the name of the table to the end of my constraint names to make them unique -- always (I'm thinking) below 40 characters. The table name for the below eg. is bioprocessors.
CONSTRAINT biomasstypeID_fk_bioprocessors
     FOREIGN KEY (biomasstypeID)
          REFERENCES biomasstypes (biomasstypeID)