Locked Rotor Alarm Signal Output (yellow wire lead): Under normal conditions a locked rotor alarm signal outputs a constant signal frequency... if the fan stops spinning or "locks", it then outputs a "LOW" condition signal. If the fan starts spinning again, the "LOW" condition signal will go away.
 
Features:
 
Dimensions: 120 x 120 x 25mm (4.7 x 4.7 x 1")
Mounting Center: 104.8mm (4.13")
Rating: 24VDC
Current: 0.18 Amps
Power: 4.32 W
Bearing: Sleeve
Speed: 2500 RPM
Noise: 43.84 dBA
Max Air: 74.5 CFM
Max Pressure: 3.8 mmH2O
Temperature: -10 to +70 C
Hours: 20000-30000
Termination: Wire leads
Weight: 150g
Impeller: Glass fibre reinforced plastic 94V-0
Frame: Die-cast aluminum