Circuit Breaker Demonstration
Investigate the working principle of circuit breaker type fuse, with this demonstration model. The apparatus is built on a robust plastic base and includes resistive loads to simulate external wiring circuits. Applications of the thermal response of bimetal strips and also electromagnetism (movement from a solenoid) are clearly demonstrated in this model.
When a 12VDC supply is connected (not supplied) the LED lights to show that current is flowing in the external circuit and the bi-metal strip can be seen to bend as its heater coil raises the temperature. After a few minutes the bending is sufficient to trip the mechanism and the current path is broken. At any current selection a short circuit situation can be initiated by pressing the red button and this produces an immediate response from the solenoid to disconnect the supply.
Earth, Neutral And Live Board Demonstration
This apparatus is an effective demonstration of how the earth wire and fuse act together to protect both the user and the appliance.
When the appliance is connected correctly and the LEDs in the appliance will illuminate to show the appliance is working. A fault is then demonstrated by swapping the live wire from inside the appliance to the case to show either the fuse melts (protecting the user and appliance) or in the case of no earth wire,the LEDs illuminate to indicate the passage of current through the person to ground. The fuse is easily visible and can be seen to ‘blow’ when a fault occurs.The unit is supplied with 10 metres of fuse wire and full instructions. A 12V D.C. power supply is required. Connections are made via 4mm shrouded sockets.