SPM Series Temperature Switch Relay

The SPM Series temperature switch relay monitors a compatible normally closed temperature switch in a pump or motor control system. Its non-volatile bistable relay retains its state through a power failure, helping preserve a latched over-temperature indication until the required reset sequence is completed.

Select SPM-120-ACA for an SPDT output and green/red status LEDs, or SPM-120-ADA for a DPDT output with no indicators. Both use a 120 VAC, 50/60 Hz control supply and an external manual reset.

Benefits for Pump and Motor Monitoring

• Keep the relay condition through a power interruption: Non-volatile latching retains the bistable relay state during power failure.
• Require acknowledgement after the switch returns to normal: The relay remains latched until the temperature switch re-closes and the reset button is pressed.
• Match the control contacts to the panel: Choose one changeover contact with ACA or two changeover contacts with ADA, using the model-specific ratings below.
• Provide local status on ACA: When powered, its green LED indicates normal conditions and its red LED indicates fault conditions. ADA has no indicators.

How Latching and Manual Reset Work

1. Normal condition: The temperature switch is closed and the relay is de-energized.
2. Temperature-switch trip: When the monitored switch opens, the relay energizes and latches.
3. Retained state: The bistable relay retains its state during a power failure. Re-closing the temperature switch alone does not clear the latch.
4. Reset: After the temperature switch re-closes, press the external reset button to return the relay to its normal de-energized state.

The reset inputs of multiple units may share one push button when the wiring polarity shown in the specification is observed.

Compare SPM-120-ACA and SPM-120-ADA

Shared Specifications and Selection Checks

Control supply / duty

120 VAC, 50/60 Hz; 2 VA; continuous duty

Temperature-switch circuit

12 VDC; 2 mA maximum

Series resistance

0–2 kΩ in series with the temperature switch

Response times

Approximately 10 ms operate; approximately 1 second release

Operating ambient

−4 to 131°F (−20 to +55°C)

Storage temperature

−40 to 185°F (−40 to +85°C)

Enclosure / socket

11-pin plug-in Style A; RB-11/PF113A shown in the wiring diagrams

Confirm the motor's temperature-switch opening and re-closing behavior, available control supply, required SPDT or DPDT contacts, contact load, socket and reset wiring. The SPM monitors switch state; the operating ambient range above is the relay's environmental rating.

Panel Mount Bracket A (100054330) can be used with the Style A housing. Follow the wiring diagram for the selected ACA or ADA model.