| Article #kba128arp |
| Typical Applications for Alternating Relays |
| Issue |
| What are some typical applications for Alternating Relays? |
| Solution/Resolution |
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. |
| This article applies to the following Macromatic products: |
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Last Reviewed: 01/25/2010 |