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    SCR Motor Controller

    Seems straightforward enough. Isee the ht-32 is discontinued but any diac with current handling and voltage rating will work, right? I see the 250k pot. I imagine the 15k resistor is for reducing trigger voltage to the gate. May I ask what is the purpose of the 3.3k resistor in series with...
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    SCR Motor Controller

    Thanks Minder. I'll study that and look up part numbers and try and understand.
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    SCR Motor Controller

    So I read a couple articles / schematics and it looks like although the triac can be triggered by both halfs (+/-) of the waveform (convenient), it also allows AC to pass through the terminals, which is undesirable for a DC motor, no? Although this will all be rectified anyway, so it won't...
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    SCR Motor Controller

    Is a triac controlled the same manner as the SCR then? Basically you recommend this: 120vac > rectified > triac with gate controlled with pot/cap > motor? No danger running the 110VDC on rectified AC, because it's average received voltage will be much lower, correct? Apologies for the crude...
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    SCR Motor Controller

    My lathe controller is pooched, so I'm going to build a new one. AKA, I'm trying to control the speed of a 110VDC 250W motor. I'm thinking SCR because it seems simple and affordable. I'm going to rectify but not filter the AC power, thereby giving me DC pulses. I'll have the SCR gate...
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    DC Motor Controller Problem (SCR/Thyristor Controller)

    I started a thread two days ago, which turned out to be caused by user error. My bad there. So I was happily using my 7x12 mini lathe for about 12 hours yesterday when suddenly it made a nice pop sound and stopped. Fuse blew. Replaced fuse. Blew again. Open up the control box and one of the...
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    What Value is this Ceramic Resistor?

    Unbelievable. Months of not being able to use this lathe and taking it apart here and there, all because of a safety switch that I didn't know existed. The two blue wires (K3 and K4) run into the head stock of the lathe which made me wonder why. Turns out there's a switch on the Chuck guard so...
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    What Value is this Ceramic Resistor?

    A few more angles if it helps. The two lower heatsinks are both d8020l, as is the top left. The two top right are both BT151's
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    What Value is this Ceramic Resistor?

    Don't mind the crummy solder job... Not a pro by any means. The heat sinks are connected to three D8020L rectifiers and two BT151 thyristors. I noticed the heatsink of one of the D8020L is electrified/not insulated. Not sure why one and not the others, but it is.
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    What Value is this Ceramic Resistor?

    Update, you're right. That wasn't the problem. This DC motor controller just stopped working one day. Can't seem to figure out why. It's off a lathe.
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    What Value is this Ceramic Resistor?

    Hmm just noticed the other part of your reply. The other resistor is ohming out correctly. The rest of the board is completely clean. It's the only obvious sign of failure I can see... I'll try the replacement and see if it doesn't fix it.
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    What Value is this Ceramic Resistor?

    Thanks. I'm replacing with a 0.05 ohm 10w resistor as that's the smallest I could source locally. This is part of a DC motor controller board which has given up the ghost. Hoping for the best.
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    What Value is this Ceramic Resistor?

    Hi all, I'm confused by a power resistor. Here is the picture. I see it's 5W but then the 0-Ohm-01J confuses me. Is this a 0.01 ohm resistor? The resistors im familiar with have decimal ratings, followed by either Ohm or R. I'm replacing it because it is burned out (other pic)
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    How to supply 5v at higher current?

    OK I didn't know that. I understood ripple and noise to be two different things. I though ripple was repeating pulses from the power supply (like when rectifying AC to DC) as part of the waveform, and that noise was like random spikes here and there caused by the way switch mode PSU's work. I...
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    How to supply 5v at higher current?

    OK. So maybe it's not figured out yet then. I'm certainly still open to suggestions. Dorke: the board has its own 3.3 regulator, so 4.6v (5v @ 92%) is still sufficient there. Ripple & noise is what I'm most concerned about here. I understand a substantial cap (bigger the better, yeah?) will...
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    How to supply 5v at higher current?

    I'm looking at the Mean Well LPV-100-5. Seems like a decent quality unit and will fit with some space to spare. Datasheet: http://www.meanwell.com/mw_search/lpv-100/LPV-100-SPEC.PDF
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    How to supply 5v at higher current?

    Sorry guys I'm not trying to be insulting by being secretive. I'm working on a new idea. Dorke, I did see those and similar units while researching. They might be a good option. My worry is voltage drop / ripple / bad power generally. Part of the load is a microcontroller that is adversely...
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    How to supply 5v at higher current?

    Ultimately, the power is coming from the mains (120v). The expected load is around 30 watts (5v @ 6A). I'd like room to grow, though, as I may add more load in the future. This is why I am looking for a 50w solution.
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    How to supply 5v at higher current?

    Hey folks... I'm trying to find a solution to supply 5 volts at a minimum of 50 watts--more would be better. The caveat is that it must be no taller than 1.5 inches (goes inside a pre-existing enclosure). Suggestions welcome :)
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    Photography Xenon Studio Flash Unit

    adamq submitted a new Showcase Item: Photography Xenon Studio Flash Unit Read more about this showcase item here...
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