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    Closed: Re: 3 phase transformer diagnosis

    Nevermind, I figured it out. Used 22 ohm 50W resistors and timed it for 0,6 seconds and it works.
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    Closed: Re: 3 phase transformer diagnosis

    Ok, thank you. Might try that. Any idea what size resistors should be and maybe about the connection?
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    Closed: Re: 3 phase transformer diagnosis

    Would star delta motor starter work to limit inrush current? Primary coil is in delta connection as standard. Or it only works for motors..
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    Closed: 3 phase transformer diagnosis

    Hi,

    Hopefully someone in here is familiar with transformers and could help me diagnose issue with one 3 phase transformer. So I bought machine which runs on 200VAC and we have 400V electrics. With...
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    Closed: Re: SmartScope ZIP 250 Z-axis

    I bought that motor I linked on second post. I connected the power only and it actuates the motor and works. But the thing is that it does not work automatically as it is not getting the encoder...
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    Closed: Re: SmartScope ZIP 250 Z-axis

    I got the service manual and it states for the motor to be Type 23, tachless. Did some google search and found that tachless would mean that it senses the speed from motor back emf, so if I...
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    Closed: Re: SmartScope ZIP 250 Z-axis

    Some more information. There is another connector for the motor. 5 wires: Chassis, one shared wire with Z-axis top & bottom limit switches (NC) and 3 other wires. I assume this is some sort of...
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    Closed: SmartScope ZIP 250 Z-axis

    Dear All,

    I saved from going to dumpster benchtop measuring device SmartScope ZIP 250. It is complete device except that it is missing Z-axis drive motor and otherwise in working condition. I was...
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    Closed: Driving stepper motor

    Hi,

    I made a small program to drive stepper motor with PIC 16F1847, TB6600 driver and 17HS2408 motor. Motor is driven 36° in every button push which equals 160 microsteps. I had no problem just...
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    Closed: Re: OP amp output oscillating

    I've taken your valuable feedback into account and added low pass filter. Signal should be somewhat steady DC voltage but in vehicle use I guess there is many interference sources.
    150840

    What...
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    Closed: Re: OP amp output oscillating

    Thank you all for helping me. This might be just bit off topic, hopefully ok. Bear with me please. I decided to ditch the idea of LM2902 & relays etc. as it was possible to achieve what I was looking...
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    Closed: Re: OP amp output oscillating

    I terminated the not used op amp, but it didn't make any differences. Could it be then so that on breadboard this is not possible to make work?
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    Closed: Re: OP amp output oscillating

    Tried cap parallel to R3, no help. I added also cap to the ic supply pin, after taking this picture. Sorry, picture is huge for better visibility.
    150776

    0.049V starts oscillating. 0.054V stable....
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    Closed: Re: OP amp output oscillating

    I isolated the microcontroller and put only BC547 transistor which controls 30mA led. Still oscillating. It is the signal from the amplifying U1:A which is noisy. As I had extra OP amp available I...
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    Closed: Re: LED light power supply fix recommendations

    Just found out that our national authority for electical safety has announced that this power source is dangerous and should be pulled off from sales. Great, not only that it is bad it is also...
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    Closed: Re: LED light power supply fix recommendations

    Just fed from lab power limited 10V and 300mA current was limiting it and voltage was 9.05V so Vf 3V. Then with 350mA voltage was 9.13V. So I need to limit the current and this should work:...
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    Closed: Re: LED light power supply fix recommendations

    I might have found the led type. Pretty certain that it is:
    https://www.cree.com/led-components/products/xlamp-leds-discrete/xlamp-xb-d

    Dimensions and outlook match. Print on that AL board XBD...
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    Closed: LED light power supply fix recommendations

    Dear All,

    Bit over 3 years ago I bought four Trio Tiber outside LED wall lights which half of them have failed. First they started blinking and then went very dim. Opened one of them and the COB...
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    Closed: Re: OP amp output oscillating

    4MHz is the crystal frequency as well. It could be that crappy breadboard or jumper wires. I've already found few not conducting jumper wires..

    Voltages are created by Lab power which can go to...
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    Closed: Re: OP amp output oscillating

    It is noisy as well and oscillating.
    Here is the oscillating:
    150738

    Here is the noise:
    150739
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    Closed: OP amp output oscillating

    Dear All,

    Here's my circuit
    150735

    When input voltage gets to 47mV LM358P OP AMP U1:A strengthens that voltage by 48 times and OP AMP U1:B compares it against reference voltage 2.18V and turns...
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    [SOLVED]Closed: Re: PIC12F683 pin high problem

    Sorry, got bit confused. You mean maybe in some other case eg. PIC16F1847 which has TRISA and TRISB and if those are set "1 = PORTA pin configured as an input (tri-stated)" it needs resistor? In this...
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    Closed: Re: Short circuit protection in PCB design

    I came across PTC multi fuse. That seems like super simple and automatically resetting and no other components needed. Is that viable option? Only thing I noticed it has around ~2ohm resistance, but...
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    [SOLVED]Closed: Re: PIC12F683 pin high problem

    Ok, that's no brainer. PIC datasheet says sink current is as well 25mA as source current so that's plenty for most transistor base currents..
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    [SOLVED]Closed: Re: PIC12F683 pin high problem

    May I borrow bit this same thread even though this is bit unrelated. Do you need pull down resistor for NPN transistor base when controlling it through PIC output? I'm pretty certain that the pic has...
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