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    [PIC] How to implement soft start in pump starter ?

    Hi

    I am designing a PIC16F887 based Submersible pump starter. Actually I am reverse engineering a product. The original product used Renesas microcontroller. It has two PCBs, one main controller board and another relay board. It also has two capacitors and on one it is mentioned start capacitor and I think the other is run capacitor.

    Capacitors

    36 MFD 440V AC
    START = 120-150 MFD 440V

    The starter has one 12V 750 mA Transformer, a bridge rectifier, a 7805 based circuit and a 3 digit seven segment display, 3 tact buttons (SET/RUN, INC/OFF, DEC/ON), one rocker for auto/manual modes selection. It has a connector and the connections mentioned are

    L, N, R, Y, B

    L and N are Line and Neutral inputs to Panel.

    RYB connects to pump.

    I have reverse engineered the controller board and have added additional functionalities.

    The original board has a current transformer which is used for auto current calibration

    Now the problem is with Relay board. Till now I had not seen the back side of the relay board.

    The relay has both quick connect terminals and PCB mount terminals. it is a 240V 30A contact relay. The line (L) goes to relay and comes out of relay. So, it is a SPST relay.

    There is a 4 Way Termianl block on the relay board and the 4 wires of the capacitors connect to the terminal block.

    On the relay board there is a MOC3021 fairchild make and two TRIACs ( I guess )at the back of the relay board, I guess because MOC3021 is on the relay board.

    Now can anybody explain the connections of the capacitors ?

    My client says that there is soft start option that is if ON button is pressed for 3 seconds then after 3 seconds expires then pump starts.

    Is this a capacitor start and run motor ?

    I found that the 2 middle pins of the 4-Way terminal block on the relay board is shorted and connected to Y terminal of RYB connector.

    The line goes to relay and comes out of the relay quick connect terminal and goes to R connector of the RYB connector.

    The B connector of the RYB connector goes to neutral and CT reads the current from neutral.

    There is a 1/2W resistor between Yand B terninals of the RYB connector.

    Can somebody explain the connections of the relay board with 2x TRIACs in detail with a diagram ?

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    Re: [PIC] How to implement soft start in pump starter ?

    If it deserves the name, reverse engineering would start with extracting a complete schematic, at least of the power circuit.


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    Re: [PIC] How to implement soft start in pump starter ?

    I will trace the Relay board connections and capacitor and connector connections to relay board and post it here in 1 or 2 days.

    For now I checked that only 4 wires from controller board connects to relay board and they are marked

    RL
    +
    S
    G

    and I guess RL is for relay driving transistors base which is a BC547.
    + is 5V for relay coil
    S is I guess signal for MOC3021 (gate signal for triacs)
    G for GND

    The MOC3021 and TRIAC labels are scratched. Only on MOC3021 I was able to see a little head part of the label. TRIAC is completely scratched but I guess I can use any 600V 30A TRIACs.



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    Re: [PIC] How to implement soft start in pump starter ?

    I found that relay used is SHENLE HAT904CSDC12. Please provide datasheet for this relay.

    Also I found by applying chalk on the scratched devices that MOC device is actually MOC3063 and the 2 TO220 package devices are SCRs 25TTS12

    Please also provide datasheet for this SCR. I need these datasheets to complete the circuit.



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    Re: [PIC] How to implement soft start in pump starter ?

    Quote Originally Posted by Okada View Post
    Please also provide datasheet for this SCR. I need these datasheets to complete the circuit
    Did you really search HAT904CSDC12 anywhere ?
    With a quick search I could find it on a local supplyer:
    http://br.onlinecomponents.com/datas...spx?p=11506877

    - - - Updated - - -

    The same with the 25TTS12 device, whose datasheet is available on the alldatasheet.com website:
    http://www.alldatasheet.com/datashee...F/25TTS12.html
    --------------------------------------------------------------------------------------------------
    Part of the world that you live in, You are the part that you're giving ( Renaissance )


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    Re: [PIC] How to implement soft start in pump starter ?

    @andre_teprom

    I actually googled but found only 3 links and they did not had the datasheets.

    Thank you for the relay datasheet. I downloaded it. The SCR datasheet page did not open for me. If possible please post the SCR datasheet here.


    Edit: Thank you. I was able to download the SCR datasheet also.
    Last edited by Okada; 24th November 2016 at 13:09.



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    Re: [PIC] How to implement soft start in pump starter ?

    Hi

    I am designing a pump starter. Attached is the relay board circuit. Question is related to this thread only.

    RL is 20V and when pump is off +ve pin is also 20V. Relay is 12V type.

    Two SCRs are used to connect start and run capacitors to pump.

    25TTS12 are the SCRs.

    Attached is the circuit of the relay board given to me.

    I guess that +ve pin voltage goes to 1.4 V (diode drop (0.7) + transistor Vbe drop (0.7)) when relay is ON.

    S pin is signal to transistor

    G is ground.

    I want to know how this circuit works. Also I think client made a mistake while drawing the SCR circuit especially the SCR connected to pin 4 of MOC3063. Am I right ?

    The diodes in the SCR circuit are 1N4007 and the one connected to base of BC337 is 1N4148.

    - - - Updated - - -

    I have made some changes after referring this circuit.

    http://www.bristolwatch.com/ele/triacs.htm

    Is the attached circuit (Proteus Circuit) correct ? If yes, how it works ? If not, what changes I have to make ?
    Last edited by Okada; 5th February 2017 at 13:06.



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