Here is a Column validation formulas for time value only input in a single line of text field:
Formula for hours, minutes and seconds(e.g.02:30:00):
=AND(TIMEVALUE(FieldName)<>TEXT(FieldName,"HH:MM:SS"),LEN(FieldName)=8)
Formula for hours and minutes(e.g.02:30):
=AND(TIMEVALUE(FieldName)<>TEXT(FieldName,"HH:MM"),LEN(FieldName)=5)
Formula for hours, minutes and seconds(e.g.02:30:00):
=AND(TIMEVALUE(FieldName)<>TEXT(FieldName,"HH:MM:SS"),LEN(FieldName)=8)
Formula for hours and minutes(e.g.02:30):
=AND(TIMEVALUE(FieldName)<>TEXT(FieldName,"HH:MM"),LEN(FieldName)=5)