If the feeder or the blender of auger filling machine does not work, it is likely that the thermal overload relay has been activated (tripped). So how do we distinguish whether the thermal overload relay has tripped? There has a photo following:
As can be seen from the above figure, the Trip Indication will help you visually distinguish whether the thermal overload relay has tripped.
All equipment has a limit to their operating range, a crane that is meant to lift 10 tones cannot lift 20 tones and if we try to do it, it will not only be unsafe, it will damage the crane itself. This analogy can exactly be applied to electrical equipment. Every electrical equipment is designed to specified load (current) and any overloading will meet the same fate as the crane.
A tendency to increase output unknowingly increases the load beyond its capacity and the capacity of the feeding system making it unsafe. Moreover, since electrical parameters are always dynamic and flexible it becomes imperative to use overload relays with electrical equipment where ever possible. Here we will limit ourselves to overload relay about electrical equipment like motors, transformers, etc.
In other words, the thermal overload relay will protect electricity safety and extend the service life of the machine’s motor.
Thermal overload relays are economic electromechanical protection devices for the main circuit. They offer reliable protection for motors in the event of overload or phase failure. The thermal overload relay can make up a compact starting solution together with contactors.
As the picture shows:
The above label A is Contactor.
The bottom label B is Thermal Overload Relay.
The current flows in cable wire from the power supply to the contactor, then from the contactor to the thermal overload relay, and finally to the motor of the load.
Some electric motors need a surge of electricity when they start up. These surges can be up to three times the current the motor uses when running at normal speed. To protect such motor circuits, thermal overloads relay works better than a normal circuit breaker because it withstands these surges without tripping. The thermal overload relay only trips when some other problem arises.
The purpose of any breaker is to protect the wiring in a circuit. A short circuit will trip any breaker, including an overload breaker. A short circuit will draw current above the overload and surge ratings and cause the relay to trip.
Several types of motor faults can cause the motor to consume too much current and trip the overload circuit breaker.
Bearing failure can cause the motor to freeze and burn.
A short circuit in the armature winding consumes too much current.
Gearbox or drive failure can cause the motor to freeze and burn.
The main purpose of the overload circuit breaker is to protect the circuit when the motor fails.
All motors have a rated load or the amount of work they can do. If the motor has to perform more work than it is designed for, it will consume too much current when trying to complete the work. Overload relays can be set to withstand temporary work overloads, just as they withstand inrush currents during startup. But if the overload condition persists, the circuit breaker will trip.
Heat can cause the motor to overwork. If the motor is in a hot climate or in a closed building without proper ventilation or cooling, it may heat up over time. When the motor heats up, even if it is not overworked or damaged, the possibility of damage exists and increases over time. The overload relay senses the increased current due to heat and trips to protect the motor.
The adjustable overload relay may be set incorrectly, causing it to trip due to normal surges or temporary overloads. The overload relay itself may also malfunction.
The 4 buttons are on the following photo: