Type B Vital Relays - Alstom

General Description
1.2.3. Relay Prongs and Plugboard
All Type B relays plug onto plugboards. Relay contacts and coil(s) are brought out
through the base of the relay as prongs. The plugboard has wedge shaped plug
insulators. There are two terminals per insulator, one on each side. The terminals are
installed from behind the plugboard. See Figure 1–4 for a simplified mating diagram. For
exact dimensions, see Table 1–2.
TOP TERMINAL
PLUGBOARD
RELAY
CONTACT
BLOCK
WIRES TO
WIRE HARNESS
RELAY
SPRINGS
INSULATOR
SLIDING
CONTACT
BOTTOM
PRONGS
TERMINAL
Figure 1–4. Plug Connection
Table 1–2. Plugboard Dimensions
Dimension B1 B2
Overall Height 9-7/16 in. 9-7/16 in.
Overall Width 2-1/2 in. 5 in.
Overall Depth 10-1/2 in. 10-1/2 in.
Diameter of mounting holes (clearance for 1/4 in. bolt) 9/32 in. 9/32 in.
Vertical distance between centerlines of mounting holes 8-13/16 in. 8-13/16 in.
There should be about a 5-inch clearance behind a plugboard to give room for wire
distribution in a relay rack.
P1457, Rev. Nov/07 1–5 Alstom Signaling Inc.