IL04906001E
Effective 03/07
2
IL04906001E
Effective 03/07
2
load (M2) is turned off, the Alternating Relay toggles back to the LOAD A position, and the process can
be repeated again. On relays with DPDT contacts, two pilot lights can be used for remote indication of
LOAD A or LOAD B status.
To eliminate any bounce condition of the Control Switch, the addition of a second switch (OFF) along
with two auxiliary contacts is recommended as shown in the Anti-Bounce Installation.
DPDT Cross-Wired Alternating Relays
Figure 3.
Typical Installations for DPDT Cross-Wired Alternating Relays
In the OFF state, both the LEAD Control Switch and the LAG Control Switch are open, the Alternating
Relay is in the LOAD A position, and both loads are off. When the LEAD Control Switch closes, it ener-
gizes the first load (M1). The red LED marked “LOAD A” glows. As long as the LEAD Control Switch
remains closed, M1 remains energized. If the LAG Control Switch closes, it energizes the second load
(M2). When the LAG Control Switch opens, the second load (M2) is turned off. When the LEAD Control
Switch opens, the first load (M1) is turned off and the Alternating Relay toggles to the LOAD B posi-
tion. When the LEAD Control Switch closes, it turns on the second load (M2). The red LED marked
“LOAD B” glows. If the LAG Control Switch closes, it will energize the first load (M1). When the LAG
Control Switch opens, the first load (M1) is turned off. When the LEAD Control Switch opens, the sec-
ond load (M2) is turned off, the Alternating Relay toggles back to the LOAD A position, and the pro-
cess can be repeated again.
To eliminate any bounce condition of the Control Switch, the addition of a second switch (OFF) along
with two auxiliary contacts is recommended as shown in the Anti-Bounce Installation.
DPDT Cross-Wired for Three-Switch Applications
Figure 4.
Typical Installations for DPDT Cross-Wired Relays for Three-Switch Applications
In the OFF state, all three switches are open, the Alternating Relay is in the LOAD A position, and both
loads are off. No action happens with the Alternating Relay or either load when the STOP Switch
closes. When the LEAD Switch closes, Load #1 (M1) turns on. When the LAG Switch closes, Load #2
(M2) turns on. Both loads remain on as long as all three switches are closed.
When the LAG Switch opens, Load #2 (M2) remains on because the STOP Switch is still closed. When
the LEAD Switch opens, Load #1 (M1) remains on because the STOP Switch is still closed. When the
STOP Switch opens, both Load #1 (M1) and Load #2 (M2) are turned off simultaneously. The Alternat-
ing Relay toggles to the LOAD B position. The entire cycle is then repeated, but with Load #2 (M2)
energized first followed by Load #1 (M1).
This type of operation is known as “Sequence On – Simultaneously Off (S.O.S.O.)” — the two loads
are energized sequentially, but remain on together until the STOP switch is opened.
If both the STOP Switch and LEAD Switch fail to close and turn on the first load, both loads will be
turned on simultaneously when the LAG Switch is closed.
Troubleshooting
If the unit fails to operate properly, check that all connections are correct per the appropriate wiring
diagram. If problems continue, contact EATON TRC 1-800-809-2772 for assistance.
L1
Lag
Lead
Lag
Off
Lead
Cross-Wired
O/L
O/L
1
2
8
3
7
6
L2
L2
L1
M1
Cross-Wired
M2
1
2
3
7
6
M1
M1
M2
M2
8
Standard Installation
Anti-Bounce Installation
L1
Motor
1
Motor
2
L2
L3
L1
M1
M1
M1
M2
M2
M2
M2
M1
L2
L1
Lag
S
witch
Lead
S
witch
S
top
S
witch
L2
L3
1
2
4
8
7
3
6
O/L
O/L
load (M2) is turned off, the Alternating Relay toggles back to the LOAD A position, and the process can
be repeated again. On relays with DPDT contacts, two pilot lights can be used for remote indication of
LOAD A or LOAD B status.
To eliminate any bounce condition of the Control Switch, the addition of a second switch (OFF) along
with two auxiliary contacts is recommended as shown in the Anti-Bounce Installation.
DPDT Cross-Wired Alternating Relays
Figure 3.
Typical Installations for DPDT Cross-Wired Alternating Relays
In the OFF state, both the LEAD Control Switch and the LAG Control Switch are open, the Alternating
Relay is in the LOAD A position, and both loads are off. When the LEAD Control Switch closes, it ener-
gizes the first load (M1). The red LED marked “LOAD A” glows. As long as the LEAD Control Switch
remains closed, M1 remains energized. If the LAG Control Switch closes, it energizes the second load
(M2). When the LAG Control Switch opens, the second load (M2) is turned off. When the LEAD Control
Switch opens, the first load (M1) is turned off and the Alternating Relay toggles to the LOAD B posi-
tion. When the LEAD Control Switch closes, it turns on the second load (M2). The red LED marked
“LOAD B” glows. If the LAG Control Switch closes, it will energize the first load (M1). When the LAG
Control Switch opens, the first load (M1) is turned off. When the LEAD Control Switch opens, the sec-
ond load (M2) is turned off, the Alternating Relay toggles back to the LOAD A position, and the pro-
cess can be repeated again.
To eliminate any bounce condition of the Control Switch, the addition of a second switch (OFF) along
with two auxiliary contacts is recommended as shown in the Anti-Bounce Installation.
DPDT Cross-Wired for Three-Switch Applications
Figure 4.
Typical Installations for DPDT Cross-Wired Relays for Three-Switch Applications
In the OFF state, all three switches are open, the Alternating Relay is in the LOAD A position, and both
loads are off. No action happens with the Alternating Relay or either load when the STOP Switch
closes. When the LEAD Switch closes, Load #1 (M1) turns on. When the LAG Switch closes, Load #2
(M2) turns on. Both loads remain on as long as all three switches are closed.
When the LAG Switch opens, Load #2 (M2) remains on because the STOP Switch is still closed. When
the LEAD Switch opens, Load #1 (M1) remains on because the STOP Switch is still closed. When the
STOP Switch opens, both Load #1 (M1) and Load #2 (M2) are turned off simultaneously. The Alternat-
ing Relay toggles to the LOAD B position. The entire cycle is then repeated, but with Load #2 (M2)
energized first followed by Load #1 (M1).
This type of operation is known as “Sequence On – Simultaneously Off (S.O.S.O.)” — the two loads
are energized sequentially, but remain on together until the STOP switch is opened.
If both the STOP Switch and LEAD Switch fail to close and turn on the first load, both loads will be
turned on simultaneously when the LAG Switch is closed.
Troubleshooting
If the unit fails to operate properly, check that all connections are correct per the appropriate wiring
diagram. If problems continue, contact EATON TRC 1-800-809-2772 for assistance.
L1
Lag
Lead
Lag
Off
Lead
Cross-Wired
O/L
O/L
1
2
8
3
7
6
L2
L2
L1
M1
Cross-Wired
M2
1
2
3
7
6
M1
M1
M2
M2
8
Standard Installation
Anti-Bounce Installation
L1
Motor
1
Motor
2
L2
L3
L1
M1
M1
M1
M2
M2
M2
M2
M1
L2
L1
Lag
S
witch
Lead
S
witch
S
top
S
witch
L2
L3
1
2
4
8
7
3
6
O/L
O/L
