Safely discharging a capacitor

[Tony Williams]

Relatively constant speed operation under variable load, without the expense of speed-sensor and controller?

[david lang]

Odd. The only experience I have is with high pressure cleaners. The el cheapo DIY jobbys have brush motors which make a terrible screaming noise - but they use them to reduce costs.

I can see the logic in that, but I've always assumed (from my HPC experiences) that induction motors were much more expensive.

Dave

[soup]

To stop the clothes getting tangled, also the stopping then going the other way will help stop areas of stagnation (and hence slow drying) occuring. Mine a "Tricity Bendix TM 220 W" certainly has this drum reversing indeed it is sold as a feature of this model and is called "reverse action".

[Andrew Gabriel]

I've got this terrible urge to dig out some perspex sheet I've got left over in the garage...

I built a Van de graff generator when I was at school, but that was rather disappointing. (On later reflection, I'm not sure the belt material I used was a good enough insulator.)

Then I built a high voltage generator using a car ignition coil, EHT valve rectifier, and a capacitor made from kitchen foil and a large roll of cellulose acetate overhead projector film. I got really 'cracking' 4"-5" sparks from it for a day, until the cellulose acetate broke down.

[Andy Dingley]

Induction is cheaper for a specific power, or for almost all large motors. Brushed is cheaper for small low powered motors that still need high torque. If you can go to a direct-drive design, then using a brushed motor and no gearbox is usually cheaper, but you need a motor that can provide the required torque on its own shaft.

[James Sweet]

Well damn, I cleaned up and tested out the Creda dryer which is the mate for the washer I've been refurbishing and it does in fact reverse the drum periodically. Nifty little machine, not like anything I've used before. If the washer was a bit larger capacity and I didn't have a big Neptune front loader already I'd definitely keep this pair but a friend of mine has more of a need for them than I do.

[Ascro]

I think that you need to understand the market they are trying to sell into. When you see the claim "A CAPACITOR stores current." you see what level they are aiming at!