Whether you can use the current relay to do motor overload protection
Motor can use the temperature protection, voltage protection, current protection is commonly used in motor protection methods, over-current protection is relatively simple to use, the effect is also more satisfactory.
Overcurrent thermal relay was originally used as an overload protection for motors. If you are talking about the current relay, of course, can be used as overload protection, the greater the power of the motor can be connected to the current transformer twice.
Do not use over-current relay to do motor overload protection! The motor current is dependent on the load, short time overcurrent, as long as the motor temperature rise does not exceed the limit, it is safe. So the motor overload protection is the performance of the accumulation of the role. Heat to a certain extent, will occur protection action. If you use overcurrent protection as overload protection, you can not set the overcurrent protection action value. If the rated current of the motor is 10A, you set the overcurrent protection value, if set to 12A. The motor long-term work in the 11.5A occasions, over-current relay will not work, but the motor is likely to damage the high temperature. If you set to 11.5A, when the motor for a very short time encountered a greater load, the instantaneous operating current reaches 13A, the relay action, and this should not be. Short time overload, the coil can not have a substantial high temperature rise, was safe, but you let it stop working, it is not appropriate. So the motor overload protection or should use the heat accumulation effect of the thermal relay, over-current relay can only be used in short-circuit protection of the occasion.
