A stationary element is provided with side members and electrode plates.
The side surfaces of one electrode plate are brought into contact with
inner walls surfaces of the side members. In addition, the electrode
surface 61 of the other electrode plate is brought into contact with the
side surfaces of the side members. One of the electrode plates is adhered
to the side members by applying an adhesive to the side surfaces of the
electrode plate and the side surfaces of the side members. The other
electrode plate is adhered to the side members by applying an adhesive to
the side surfaces of the electrode plate and the side surfaces of the side
members.
