Monthly Archives: July 2017

The Motor Circuit Breaker – Information

The function of the motor circuit breaker is the protection, because it interrupts the passage of the current when overload occurs, this will happen with a thermal trip. Overloading occurs when a current exceeds the nominal current over a prolonged period, damaging the cable and the equipment.

The protection provided by the circuit-breakers saves costs, physical space and enables a quick reaction condition in the event of short circuits, turning off the engine in a matter of milliseconds.

The motor circuit breaker protects the main circuit, and combines control and protection in a single device. They work to turn the electric motors on and off manually, and ensures protection against short circuits, overload and phase failure.

ac motors at mrosupply

Circuit breakers are reclosable and do not require replacement and can be used as a session key. They have high interruption capacity and even in installations with high short-circuit current can be used, ensuring total protection. It must be set to the nominal value according to the motor.

If it undergoes overload the blade system will become deformed by turning off the circuit. In this case the protection will happen through a magnetic device, turning it off almost immediately.

The Three Phase Motors

The three-phase induction electric motor is the most used type, not only in industries, but also in the domestic environment because it has most current three-phase AC power distribution systems. The use of three-phase induction motors is indicated from 2 KW. For smaller power units, the use of single phase power supplies is indicated. The three-phase induction motor offers advantages to the single-phase, for example, has easy start-up, very low noise level and reduced price for power above 2KW.

The squirrel cage engine is the most used in the industry today, since it is cheaper in relation to single-phase motors, not only in its construction, but also in its use. Otherwise, if you make the ideal choice of the boot method, it will have a wider range of applications. The squirrel cage rotor is formed by a core of ferromagnetic plates, isolated from each other, in which are placed the conductors, disposed parallel to one another and joined at their ends by two aluminum conducting rings, which generates a short- Circuit in the conductors.

Convenient Loading of Engines

An electric motor is designed so that it can provide a nominal torque Cn, at a nominal speed Nn. That is, for a nominal power Pn, we consider the expression Pn = Cn x Nn. It is important to note that the electrical losses, also known as thermal losses, change according to the square of the resistant torque, which is the load.

In a well sized motor PL112600, this rugged torque must be smaller than the rated torque. If it is equal to or slightly higher, the resulting heating will be considerable. However, a motor considered underloaded will exhibit a noticeable reduction in performance. The ideal loading would have to match the workload that will be done, which is often not easy to determine.

If the work required of the driven machine has temporary overloads,

The engine power needs to be slightly higher than the power required. It is also important to limit the increase in losses by performing proper maintenance of the machines and their mechanical drive components, such as clearance regulation, proper lubrication and alignment checking, among others.