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Simple and reliable three-phase motor phase loss protection circuit

Published on Apr 18 2011 // Protection Circuits

Simple and reliable three-phase motor phase loss protection circuit.

Figure, buttons SB1, SB2 and composition of motor contactor control circuit K through SB1, SB2 to control the motor run and stop. J for the installation of the phase and phase sequence protection relay, J1 and J2, respectively, for normally open and normally closed contacts. Power normal state of the relay J is the pull, if the motor in the run-time phase for some reason, J immediate release, J1 disconnect, contactors K release, cut off the motor power supply, which play a role in protecting the motor. J2 connected at the same time, the indicator light L, S buzzer rang. Power if the motor before the start of phase, wrong does not equal the normal, the protection circuit can prevent the motor starting, and can alarm.
  J XJ3-G relay lack of phase with the phase sequence protection relay, which uses integrated circuits and new technology, the voltage sampling method, and is independent of the protected motor power, without any current level of tuning and adjustments to the motor before the start of any phase occurred in the operation phase, the wrong protective effect equal to failure. In addition, when the three-phase voltage asymmetry is greater than 13% can move, play a protective role.
  J, 1,2,3 termination relay three-phase power, 5,6 end is normally open contact, 7-8 end is normally closed electric shock. If the motor does not start after installation, indicating XJ3-G differential phase sequence relay has been work, just XJ3-G relay 1,2,3-side swap any two lines, the electric motor that is able to start properly, then the phase sequence already identified.
  The circuit is easy to install, protected, reliable, low cost. Three-phase asynchronous motor can play a very good protection. Since the phase protection circuits using the above six months, the motor is running has been very stable, protection circuit is also very good.