Electromagnetic speed control motor maintenance example
Electromagnetic speed regulating motor, due to its economical and practical, easy to operate, is still in use in some occasions requiring stepless speed regulation. A few days ago, a 3 kW electromagnetic speed-regulating motor has been operating normally since its installation. The electromagnetic speed controller fuse is blown when driving this day.
1. Fault phenomenon When the switch is closed, the red indicator of the controller lights up after the power is turned on. The squirrel-cage asynchronous motor is operating normally and there is no abnormality in the controller. When the controller external body potentiometer w1 is operated, when the speed is to be changed, the fuse is immediately blown.
2. Analysis of the cause of the failure may be caused by a problem inside the controller.
First, the freewheeling diode GZ and the thyristor KZ are soldered from the circuit board, and the multimeter is inspected, and the varistor Ry is also normal. After that, the phase shifting, pulse and other related components were checked, and the parts were also normal. After diangon.com, the DC output terminals 3, 4 of the controller are disconnected from the excitation winding of the electromagnetic clutch, and the incandescent lamp with 220 volts and 100 watts is tested. As a result, the brightness of the incandescent lamp changes smoothly with the knob adjustment of the potentiometer. The tube was not blown, and thus the controller was no problem.
It can be basically determined that there is a problem with the coil of the electromagnetic clutch. The excitation coil is measured with a multimeter, and the resistance is less than 20 ohms (normally the coil is about 40 ohms).
3. Trouble-shooting Remove the electromagnetic clutch coil, taking care not to damage the winding of the tachogenerator, and properly store the parts, and then re-wind the data according to the field winding. After the dipping paint is dried, it is installed in the original position. And use epoxy resin to fix it to prevent loosening. After the installation is completed, it can be used directly on the market. There is also a situation, reminding peers to note that the controller power supply (220V) phase line must be taken under the autonomous motor contactor to avoid burning the excitation coil!
