overspeed alarm indicators of electric motor with digital rpm indicator circuit diagram and operation

[jaseela123d]

The overload indicator is built around the operational amplifier CA3140 (IC1). Set the reference voltage (depending on the desired speed) by setting the VR1 preset on pin 2 of IC1. When the voltage developed at the pin 3 of IC1 is greater than the reference voltage at the pin 2, the output pin 6 of the comparator IC1 rises to the sound pickup PZ1 and illuminates the LED 3. The rotation indicator circuit is built around Of the AND gate 74LS08 (IC2). The pin 2 of the gate N1 rises as the motor rotates in the forward direction, whereas the pin 1 of the gate N1 is raised through the resistor R2. When both pins 1 and 2 are high, the output pin 3 of gate N1 is set high to turn on LED1. Similarly, the pin 5 of the N2 gate rises as the motor rotates in the reverse direction. When both pins 4 and 5 are high, the output pin 6 of gate N2 rises to turn on LED2.