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    ST70 power supply questions

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    peterh

    Posts : 816
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: ST70 power supply questions

    Post by peterh on Wed Oct 26, 2016 7:05 am

    No i have not. But it seems much more motivated with a soft start then a delayed start.
    Did you find this softstart as a module or board somewhere ?

    ureche

    Posts : 12
    Join date : 2016-09-11

    Re: ST70 power supply questions

    Post by ureche on Wed Oct 26, 2016 11:07 am

    I found the schematic somewhere on a forum, i can't remember where. I want to incorporate the design directly onto a psu pcb, along with the tdr.

    In Proteus it seams to work pretty nice. I've asked because i was wondering if this circuit would arise any problems Smile.

    I want to place an inrush thermistor on the ac side, to limit the spike to the cold heaters. Then 20-30 seconds delay to allow the heaters to get hot, and then raise the B+ in about 5 seconds.

    ureche

    Posts : 12
    Join date : 2016-09-11

    Re: ST70 power supply questions

    Post by ureche on Fri Nov 11, 2016 10:26 am

    Hi, i have a question regarding the power transformer and heater winding. Are there any disadvantages in paralleling the two 6.3v heater winding? Connecting both channels would induce hum?

    Also are there any disadvantages in ordering a PT with only one winding but with the rating of 10A ?

    Thanks.
    avatar
    peterh

    Posts : 816
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: ST70 power supply questions

    Post by peterh on Fri Nov 11, 2016 11:40 am

    ureche wrote:Hi, i have a question regarding the power transformer and heater winding. Are there any disadvantages in paralleling the two 6.3v heater winding? Connecting both channels would induce hum?

    Also are there any disadvantages in ordering a PT with only one winding but with the rating of 10A ?

    Thanks.
    I don't think it's a good idea to parallell 2 windings. And differences will cause huge
    currents to load the transformer to no use.
    Note i say "parallell". Serial connected windings are ok ( but limited in current
    to the winding with lowest current capability)


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