ABB MG-6 Instruction Leaflet page 3

MG-6 Multi-Contact Auxiliary Relay
2.2 Armature and Moving Contacts
The steel armature has projecting sections at the sides
near the center, which act as knife-edge bearings
and rest on supports that are a part of the molded
base. A stud attached to the core leg of the lamination
stack extends through a hole in the lower end of the
armature. A self-locking stop-nut on the outer end of
the stud is used to limit and adjust the travel of the
armature in the de-energized direction.
The upper end of the armature has an adjustment
screw (Figure 1, Item 6) to which one end of the
armature restraining spring is attached. In both the
hand and electric reset versions of the relay, a latch
screw (Figure 1, Item 5) is mounted at the extreme
top end of the armature. For the self-reset relays, the
latch screw is replaced by a set screw which serves to
slightly separate the locking plate from the armature.
Located between the spring adjustment screw and
the latch (set) screw is a third screw, which when
tightened, applies pressure to the former screws and
effectively locks them in place.
The ac rated MG-6 relay can be used with any
combination of contacts, but the dc relay can have
Figure 1 - Front and Side Views of MG-6 Relay with Electric & Hand Reset (Cover Removed).
1 = Reset push rod
2 = Stationary contact
3 = Moving contact
4 = Moving contact spring assembly
5 = Latch adjustment screw for armature
ABB
up to four circuit opening contacts with the normal
operating spring adjustment. With more than four
"break" contacts, the operating spring should be
adjusted to give the correct back contact follow (see
Section 6.4 CONTACTS).
The moving contact fingers are mounted on a molded
insulation plate attached to the armature. Silver
contact buttons are on both sides of the fingers so that
they may be used as either circuit-opening or circuit-
closing contacts. The fingers are assembled on guide
pins between two springs so that a definite spring
compression and contact wipe is assured for either
the contact-closing or the contact-opening conditions.
Flexible leads are connected to the contact fingers.
The armature assembly has the contact fingers located
above and below the bearing points so the weight is
partially balanced about the bearings, leaving less
chance for severe shocks to move the armature. The
corresponding stationary, large silver button contacts
can be installed to mate with the moving contacts
when the armature is in either the energized or de-
energized position.
6 = Adjusting screw for armature spring tension
7 = Reset coil
8 = Operate coil
9 = Optional operating coil cutoff contact
IL 41-753.1 N
3