Alternating Relays are used in duplex control (pump control) applications where the optimization of load usage is required by equalizing the run time of two loads. They are also used where additional capacity is required in case of excess load requirements. This alternating action is initiated by a control switch, such as a float switch, manual switch, timing relay, pressure switch, or other isolated contact. Each time the initiating switch is opened, the output relay contacts will change state, thus alternating the two loads. Two LED indicators show the status of the output relay.

Alternating Relays are available in three output configurations: SPDT, DPDT and DPDT cross-wired. See "Typical Installations" below for more information.

Each version is available with an optional three position selector switch. This allows the unit to alternate the two loads as normal, or lock the relay to one load or the other. By locking the Alternating Relay to one load, the other load can be removed for service without rewiring the first load for continuous operation. The selector switch has a low profile to prevent any accidental changes in status.

• For Duplex Control (Pump Control)
• Control Voltages of 12, 24, 120 & 240VAC
• Compact plug-in case utilizing industry-standard 8 or 11 pin octal sockets
• Three 10A output contact configurations: SPDT, DPDT, or DPDT Cross-Wired
• Optional low profile selector switch to lock in one sequence
• 2 LED's indicate relay status
• with socket

Application Data

Voltage Tolerance: +10%/-15% of control voltage at 50/60hz.
Load (Burden): 3VA.

Output Contacts:
DPDT 10A Resistive @240VAC/30VDC, 1/2HP @240VAC

Life:
Mechanical: 10,000,000 operations
Full Load: 100,000 operations

Temperature:
-28^o to 65^oC (-20^o to 150^oF)

Transient Protection: 10,000 volts for 20 microseconds

Indicator LED's: 2 LED's marked LOAD A and LOAD B

Optional Selector Switch Settings:
ALTERNATE
LOAD A
LOAD B

Approvals:

with socket

Dimensions

Typical Installations

The loads in the following examples could be pumps, compressors, or air conditioning/refrigeration units:

SPDT & DPDT

In the off state, the Control Switch is open, the Alternating Relay is in the LOAD A position, and both loads (M1 & M2) are off. When the Control Switch closes, it energizes the first load (M1). The red LED marked "LOAD A" glows. As long as the Control Switch remains closed, M1 remains energized. When the Control Switch opens, the first load (M1) is turned off and the Alternating Relay toggles to the LOAD B position. When the Control Switch closes again, it energizes the second load (M2). The red LED marked "LOAD B" glows. When the Control Switch opens, the second 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.

DPDT Cross-Wired

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 energizes 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 position. 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 second load (M2) is turned off, the Alternating Relay toggles back to the LOAD A position, and the process can be repeated again. NOTE: if the Lag Control Switch does not close while the Lead Control Switch is closed, the Alternating Relay will act as a normal unit.