Recent Posts

1

Projects, Designs, and Technical Stuff / Re: Insulation between motor laminations?

« Last post by TimNJ on Today at 12:42:09 pm »

I mean, it’s just the stator by itself right now, fairly easy to clean.

2

Power/Renewable Energy/EV's / Re: SMPS input filter cut off frequency

« Last post by mtwieg on Today at 12:40:22 pm »

The reasoning is likely as follows:
The power supply's control loop will attenuate line disturbances below the controller's crossover frequency.
The LC filter will attenuate disturbances above its cutoff frequency.
In order to attenuate disturbances at all frequencies, then these two bands should overlap, thus the LC filter fc should be lower than the controller's crossover fc.

Of course, whether this is actually worthwhile is very application-specific.
For example, if your primary concern is just passing EMC tests, then there's not much reason to attenuate below 150kHz (or whatever the lower test frequency your device requires).

3

Projects, Designs, and Technical Stuff / Re: Insulation between motor laminations?

« Last post by moffy on Today at 12:39:55 pm »

Sanding or wire wheeling will produce metal swarf which can go anywhere, not really desirable.

4

Manufacturing & Assembly / Re: Vacuum Pick-Up Tool for Rework (Includes video of my own design)

« Last post by tooki on Today at 12:34:04 pm »

You may be right, I thought that switch has 12V output. Any recommendation for footswitch that would have directly the 12V output?

How would it? There’s no standardized 12V plug, unlike the 120V mains plug and receptacle.

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Projects, Designs, and Technical Stuff / Insulation between motor laminations?

« Last post by TimNJ on Today at 12:34:02 pm »

Greetings,

I have an old radial arm saw that I’m rebuilding. I’ve cleaned it up, put new bearings in the motor and now want to paint it. The motor has exposed laminations on the body, presumably to save space or something.

As far as I know, there’s usually insulation between laminations, perhaps in the form of “backlack” or other varnish-y type material. Is this insulation also applied to the edges of each lamination? If I were to sand or wire wheel off the existing paint, do I run the risk of removing insulation and causing some lamination to lamination shorts? My thought is that the distance between laminations is already set by the thickness of the insulation between lamination, so I wouldn’t be shorting any together unless i applied severe pressure, enough to deform the laminations “into each other”.

Any thoughts?

Thanks,
Tim

6

Beginners / Re: Convert US standard 115V to International 230V

« Last post by radiolistener on Today at 12:32:28 pm »

Somehow we need to get through to you that you have got to be more receptive to feedback and more accepting of others’ expertise, and to make a real effort to read carefully and thoroughly before responding to threads.

I don't know why you decided that I don't listen to feedback. Regarding to the point that OP uses PSU which is already compatible with both standard, I heard this argument and accepted it. But I didn't agreed that this is enough info to make decision that there is no change required for medical device. IanB tried to ague that the medical device power consumption can be checked with a cheap Chinese meter and that information can be used to decide if used power supply is enough. But I argued that such approach is not acceptable for medical devices. Then Zero999 decided to support IanB mistaken idea that there is nothing to worry about and all can be checked with cheap meter. And then you're join and support Zero999...

As I can see you're didn't listen to my feedback. Instead you're started to blame me that I don't listen.

Usually person starts to blame some other person when he don't have enough knowledge for proper argument on the subject, that's the child way for discussion. And I see that you're started to talking about persons instead of topic subject. Isn't it?

7

Security / Re: Microsoft repackages apps with a telemetry .NET wrapper

« Last post by tooki on Today at 12:30:13 pm »

Some developers use telemetry to figure out how people use their software

Shouldn't that be done in-house, or at minimum with users that agree to be monitored?

But users do agree to it. That’s why software installers literally ask you whether you agree to share usage data or not. Any legitimate vendor makes it clear what is and isn’t collected. (For example, that your data itself won’t be shared.)

Are you happy with your car telling the manufacturer where you went, what speeds you did where, how you used the brakes, your acceleration, where you were looking, how you flash the lights, etc? What time you go to work, the shops, hey - is that the place where Ms Periwinkle's car is parked and it's always 8pm to 10pm?

Completely different from usage statistics.

A correct analogy would be that it shares things like: what percentage of the time is your foot on the gas pedal? How many times do you use the brake on a typical drive? What’s the average length of your drives, in km and in minutes? What’s your acceleration style (jackrabbit starts or slow off the line)? How long is the car idle between drives?

The stuff you list is more like if Word was sending not only that, but also uploading your documents and a live keyboard log.

I am absolutely aware that some companies, like Google and Meta (and the essentially scammers who make “free” phone apps whose main raison d’être is to collect user data), do collect and upload all kinds of sensitive personal data, like location logs, to use for commercial purposes. But not all software companies do, and it’s unfair to extrapolate the true offenders into being typical of the entire industry.

8

Projects, Designs, and Technical Stuff / Re: Heated Ferrite == Useless Ferrite

« Last post by strawberry on Today at 12:28:57 pm »

flyback winding polarity is crucial and proper airgap too
it will lead to blown or overheating switching device (not loaded)
and wrong turns and incorrect layer orders will lead to poor performance or safety (EMI, less power/voltage..)

applying heat ~160deg C may damage winding insulation(cheap wire is rated max op 150)

9

Beginners / Re: Resistor ????

« Last post by Herschel on Today at 12:26:35 pm »

https://www.digikey.in/en/resources/conversion-calculators/conversion-calculator-resistor-color-code?_gl=1*1d14nck*_up*MQ..&gclid=EAIaIQobChMI-LiPqK_ihQMVaYbCCB22yA3REAAYASAAEgI6OPD_BwE

80 ohm 1% ?

is the second band grey or silver? i have never seen a resistor with 2nd silver band like this before...
 
just use a mulimeter...

10

FPGA / Re: Help on translate schematics to Verilog.

« Last post by tggzzz on Today at 12:23:22 pm »

Hi,
I need to translate into Verilog some KiCad schematics and came across the attached symbols.Is the first a tristate buffer and the latter two AND gates tied to a NOR gate?How to code them in Verilog (well, I use Quartus schematics for now...)?Thanks in advance

You should think in terms of "translating" the specification/function implemented by the schematics into the equivalent specification/function implemented in an FPGA.

Trying to translate gates means that - at best - you will end up with the same bugs. Normally you will also end up with a lot of irrelevant detritus which will slow the operation down and be space inefficient.

If you are familiar with software, think of your question as being how to translate an C statement into an ADA statement. The C statement is very permissive w.r.t. overflows, concurrency, valid values. Do you need top ensure the ADA statements preserve those properties?