Charms can be protective, one imagines (7)
I believe the answer is:
amulets
'charms' is the definition.
(amulet is a kind of charm)
'be protective one imagines' is the wordplay.
I cannot really understand how this works, but
'be' could be 'am' and 'am' is located in the answer.
This explanation may well be incorrect...
'can' is the link.
Can you help me to learn more?
(Other definitions for amulets that I've seen before include "Ornaments worn as charms against evil" , "Lucky charms" .)