The starting current of the motor 2

As is known to all, since the decoupling decompression starter the biggest advantage is starting torque is bigger, when the tap at 80%, starting torque can be up to 64% of direct starting. Set the starting torque of the motor is 1.4 times of its rated torque, in the reduced pressure, starting line current perkins diesel generator is 64% of the direct starting, starting torque is 90% of the rated torque. According to the survey, however, since the decoupling decompression starter mostly work in 65% tap place, but also a starting smoothly. According to the analysis, the starting torque of the motor at this time and for direct starting at 42%, compared motor vehicle spare parts with star triangle when starting a third, just big 8 ~ 9%. Can be expected, on this occasion the star delta starter also have not cannot, and indeed there are feed mill, water pumps and other USES star triangle decompression starter and functioning example. If consider the promotion of asynchronous motor with high starting torque, star triangle has wide foreground application more starting ways. Star delta starter can be implemented by way of manual operation and automatic control. Figure 1 is the star delta starter circuit automatically, which is to use a button and ac contactor to realize the automatic operation line, b is the use of time relay and ac contactor to realize the automatic operation line. Now after pressing a line to introduce the working principle of automatic star delta starter. Start, press the start button QA, contactor YC immediately action, its main contact to the stator windings into Y connection for starting: its auxiliary normally open contacts will contact QC coil circuit connected, make it, turn on the main circuit, the auxiliary normally closed contact is to cut off the contactor coil circuit of SC, lest by SC main contactor closing current short circuit accident. So it will be according to the motor, Y connection starting. Because of the time relay SJ in QA press after the electricity. So, after setting the time delay of the often open contacts, to cut off the YC coil circuit, make the YC release, SC, and motor run full pressure under the delta connection. At this point, the starting process is over, time relay coil circuit has been cut off by auxiliary normally closed contact of SC. QX3 series automatic star delta starter basic technical data listed in table 1. The starter set for overload protection of bimetal thermal relay and bimetal used www.facebook.com/guohong.trading as delay time relay, contactor is also used to connect and breaking circuit, so also has the protection of pressure loss. Since QX3 series automatic star delta starter is braking is used for motor control, natural its circuitry is consistent with the circuit shown in figure 1 b.