Motor speed control on AC motor?

XD351 reminds us:

I can't reproduce any of the pages on this project here - copy- right infringements .

This is generally true, but there is an escape clause in the copyright rules (at least in the UK, and I believe much wider). A copy made for private research purposes is not an infringement - so when you have stuff that would interest one (or a few) individuals, you can copy to him (them) but not on a forum which tells lots of people.

This is one use of the 'private message' system used on this site (and others).

I hope this helps to remove barriers to the sharing of knowledge lawfully.

Cheers, Tim

'Copies for research' should be single copies or short extracts only, and made for your own use.

I.e you can borrow a friend's copy and scan/photocopy an article or extract.

You can't make multiple copies or share them.

Strictly speaking you can't make a copy for someone else, but you can lend them your item to copy.

Sorry, if I have restored the barriers to sharing of knowledge.

Neil

www.copyrightuser.org/understand/exceptions/private-copying/

www.copyrightuser.org/understand/exceptions/research-private-study/

Not quite!

Well it is 100% safe when its not plugged in to the mains, but its then not a lot of use.

Even if all your sockets are wired correctly, the Variac output is not isolated unless you have an isolating transformer. With care, and in controlled situations it might be acceptable for someone who knows what they are doing, to work on non isolated equipment, but I doubt it would be described as good practice.

Theoretically neutral is at 0 volts and is usually linked to the the earthing system, but RCDs or ELCBs will still be triggered when neutral is shorted to ground.

Providing the equipment you are feeding with the Variac is double insulated or is intended to be plugged in to a normal mains socket then a non isolated Variac has no effect on safety (unless there are other consequential problems from running something outside its rated voltage ratings).

Ian P

All i know is it clearly states in the column next to the editorial :

All material is copy write © . No part of this publication may be reproducd without the written consent of the publisher.

Good enough for me !

Besides that i'm pretty sure the publisher of MEW/ME wouldn't be too pleased if i started posting pages or articles out of those magazines on this or another forum for all and sundry to read for free ! 

Ian.

Edited By XD 351 on 31/01/2018 04:23:48