R-K Electronics, Inc. Protection Relays & Systems STR-24A-B

The STR is a seal and temperature status relay designed to monitor submersible pump motor sensors for seal leakage or open temperature switches. It accepts 24VAC supply voltage and features pluggable terminal blocks for connection. The relay has two SPDT outputs rated at 5A at 120VAC, 6A at 277VAC, 1/8HP at 120/277VAC, and 5A at 30VDC. It operates in ambient temperatures from -40°C to 65°C for the tabs and -40°C to 60°C for the terminal blocks, with storage from -40°C to 85°C. Mounting is surface mount with epoxy fill, and the unit weighs 1 pound. The relay monitors resistance levels: a seal fault triggers below 330Ω, and a temperature fault triggers above 1,500Ω. Adjustable resistance trip points from 5KΩ to 200KΩ and reset options are available. A 16-character, two-line backlit display shows status.