Detail AUXILARY REALAY MVAA AREVA / ALSTOM
The type MVAA is a low burden
auxiliary relay which can be used
where a scheme demands several
contacts for event recording, alarm
initiation, contact logic
The relay can be supplied fitted with
normal duty contacts and/ or with
heavy duty blow-out contacts.
MVAA relays are voltage operated
attracted armature units of compact
design with a positive action and a
high degree of mechanical stability.
Voltage is applied to the relay coils
via an internal diode bridge which
enables relays to be energised from
ac or dc power supplied. All relays
comply with IEC 60255.
Figures 2 and 3 show typical
diagrams of relay types MVAA 11
and MVAA 14 respectively.
Contacts are constructed from
silver/ copper alloy, shaped and
positioned to ensure very reliable,
low resistance operation.
Normal duty make, break and
changeover contacts and heavy
duty magnetic blow-out contacts are
available in various combinations.
See Tables 1, 2 and 3.
Heavy duty magnetic blow-out
contacts are recommended for
breaking heavy or highly inductive
dc loads. When these are fitted, the
number of contacts available may
be reduced. See Table 3.
Breaking capacity curves for these
contacts are shown in Figure 4.
Each relay element is supplied with
an optional hand reset operation
indicator. The indicator consists of a
mask which on operation drops to
expose a broad red strip positioned
diagonally on a rectangular white