Motor protector 10

Published:2011/4/27 20:49:00 Author:Ecco | Keyword: Motor protector | From:SeekIC

The motor protector described in the example can cut off the power supply when any phase of power in three-phase AC motor being lacking, it can prevent winding overheating damage due to broken phase operation. The working principle The motor protector circuit is composed of the voltage detection circuit and protection controlling execution circuit, it is shown as Figure 8-46. Starting control circuit is composed of stopping button Sl, starting button S2 and AC contactor KM (the original motor starting circuit). Voltage detection circuit is composed of the diodes VDl-VD3, Zener diode VSl-VS3, resistors Rl-R6, capacitors Cl-C3 and optocouplers VLCl-VLC3. Protection control circuit consists of transistors V, relay K, the diode VD4 and resistor R7. Rl, R3 and R5 use 1-2W metal film resistors; R8, R4, R6 and R7 use 1/4W carbon film resistors or metal film resistors. Cl-C3 select aluminum electrolytic capacitors with voltage in 16V. VDl-VD4 use 1N4007 silicon rectifier diodes. VSl-VS3 select lW, 9 · IV silicon voltage regulator diodes. V uses S8050, 3DG805O, BC136 or other models NPN silicon transistors. VLCl-VLC3 use 4N25 or MCT2E, TL206 coupler. K uses 9V DC relay.



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