Guineafowl's latest activity

Got it. Trace 1 to show CH1+CH2, invert 2 to get CH1-CH2.

Fluke manual. https://media.fluke.com/c3705bf5-ce6e-4b79-8f55-b10800bf4fdc_original%20file.pdf

Yes, it’s been two house moves since I last saw the Hameg manual. As I remember it, the ADD/CHOP button selects dualling options: ADD...

I’m not sure either of these have the subtract function, but willing to be corrected. My earthing is TN-S, ie N and E linked at the...

One final problem: the VFD output is mains-referenced, so connecting the probe across phases will trip the RCD. Unless the motor earth...

Cheap and cheerful, I’m afraid: https://www.aliexpress.com/item/1005006427487406.html I have a Hameg HM203-5 20 MHz CRO, and a...

Thanks - I see the difference between an RC LPF and the snubber. I’ve ordered a 20-pack of ferrite rings at those dimensions, and have...

Here is a crude first guess at what you need. It has max attenuation at VFD 3 kHz, 0 dB at 50 Hz. The motor model is a guess, now...

No circuit diagram, even in the manual for the decent VFD. At some point, I’ll get around to dismantling one of them as you suggest, but...

If possible connect the Y of snubbers mid-point to the neutral, avoid a ground connection. If no neutral, design delta a snubbers, or...

Something like this?: I’m not sure if the star point of the snubber should be earthed; all circuits in my shop are RCD-protected to...

No, because the sound isn’t a problem - it’s not annoying - and happens on even the newer motors. On some battery drills, when you just...

There are several motors that might need this modification, one being a Newman ‘Elf’ from 1961, for which I can’t find a datasheet. It’s...

I can hear the 3 kHz switching frequency, yes...

I have a couple of old CROs, but not the right probes for connecting up. The VFD/old motor problem is described here...