Electric valve motor control circuit

The electric valve control circuit consists of the following three parts: main circuit, control circuit and energy consumption braking line aa. , The main circuit includes the power switch
    scene.
QF, the main contacts of three-phase AC contactors KM1 and KM2, components of thermal relay FR and three-phase AC motors, etc. The control circuit includes
control buttons SB1-SB5, lines BH of AC contactors KMl-KM3 and their auxiliary contacts, power transformers Tl and T2, signal
indicators HL1-HIA, flash switches Sl and S2, and status selection switches SA1 and SA2. And position switches sQl, SQ2, etc. The energy consumption circuit includes
the bridge rectifier uc, the current limiting potentiometer RP, the energy storage capacitor C and the main contact of the AC contactor KM3, etc. The electric valve motor control
circuit is shown in Figure 4-35.
    When the line is in hot standby state, you can determine whether the main line is controlled or uncontrolled by selecting the switch positions of SA1 and SA2. When SA1
(SA2) is on the left, the coil of KM1 (KM2) exits. Run t When SAl (SAZ) is on the right, the coil of KMl (KM2)
is put into operation. When SA1 (SA2) is on the left, the signal indicator light lights up. The operator or maintenance personnel can use this gear to check
whether the control circuit is working properly. When SA1 (address) is on the right, the signal indicator light does not light up. Only after the valve motor is started, the signal indicator lights
HL1 and H12 (HL3:, .HIA) will flash. Turn on the power switch QF, place the selector switch SA1 to the right, press SB1 (or
SB2), and the current will pass through Vll - SBl (or SB2) - KM2 contacts (2-3) - KM1 coil --s02-- SAl - FR contacts (7-9)
- KM3 contacts (9-10) - SB5 - Wll. The KM1 coil is electrically activated and self-magnesium, and the valve motor rotates to open the valve. After the contact (5-6) of KM1
is connected, the flash switch sl works, and the red light HL1 and green light HL2 are used as flash indication. When the valve opens to the limit position,
SQ2 is disconnected, the coil of KM1 loses power, its main contact is reset, the power supply of the valve electric coil is disconnected, and the valve motor stops working.
  Place the selector switch SA2 to the right, press SB3 (or SB4), and the current will pass through Vll-SB3 (~a'SB4) -*KMl's ​​contacts
(13-14)---KM2 coil-,-SQl- *SAZ - FR contacts (7-9) - KM3 contacts (9-10) - SB5 - Wll, the KM2 coil is electrically attracted
and combined with the self-linked cabinet door motor to rotate and close the valve. After the contacts (12-15) of KM2 are connected, the flash switch S2 works, and the red light HL3
and the green light fflA serve as flash indications. When the valve is closed to the limit position, the position switch sQl is turned off. The coil of KM2 loses power, its main contacts are reset, and
the power supply to the valve motor is disconnected.
  During the opening and closing process of the valve, if the stop button SB5 is pressed, its moving contact will be disconnected, causing the KM1 or KM2 curve coil to lose power
and release, and the motor will lose power. at the same time. The moving contact (19-W11) of SB5 is closed. The KM3 coil is electrically closed, and its contacts (9-10) are opened to
prevent KM1 or KM2 from malfunctioning. The main contacts of KM3 are closed, allowing the output of the bridge rectifier and the energy storage of the capacitor to act on the winding of the motor at the same time
. Generates braking torque, causing the motor to stop instantly. In this way, the door can be stopped at the designated location accurately and as required.
    In Figure 4-35, the potentiometer RP plays the role of current limiting. The braking current can be obtained by adjusting RP. Usually the energy consumption braking current is 4.5A. In Figure 4-35
, the electrolytic capacitor can be selected according to the power of the valve motor. If the power of the valve motor is below 2kW, a capacitor of 100-ZOOlJLF' can be used
; if the power of the valve motor is between Z~5.5kW, a capacitor of 100-Z001JLF' can be used. Choose a capacitor of about 400t, F. The withstand voltage of the capacitor is above 600V.