Talk:Liquid rheostat

Comment

It's a very long time since I've used this type of load bank, for locos, it brought back some memories. They did have the advantage of simplicity, requiring no external power sources or supplies, other tnan water, and were so low tech that they could be fabricated on site. Suckindiesel (talk) 07:37, 13 May 2009 (UTC)

Suckindiesel - please add some comments form your personell experience here:

http://www.claverton-energy.com/turn-your-standby-generation-into-profit-making-assets.html#comment-889

some ill-informed people are unaware of how useful these devices are in remote areas and quite safe in the right hands....Engineman (talk) 11:20, 14 May 2009 (UTC)

They're no more dangerous than Electric heating#Electrode heaters, which work on the same principle, but with plain water, provided the correct precautions are used. This requires connecting the container to both ground & neutral and breaking all poles with a linked overcurrent circuit breaker. BS 7671:2008 spells it out. Suckindiesel (talk) 23:44, 15 May 2009 (UTC)

Is this correct?

Quote: "Power dissipation was about 1 MW, at a voltages of about 700 kV and current of about 1,500 A". I don't know what application is envisaged here but 700 kV sounds over the top. I suspect it should be 700 volts. Biscuittin (talk) 00:26, 2 November 2009 (UTC)

Yes, your're correct, should have read 700 V. Suckindiesel (talk) 15:51, 2 November 2009 (UTC)

Thank you, I have amended it. Biscuittin (talk) 17:39, 2 November 2009 (UTC)

Corrosion

I'd have thought the corrosion problem could be minimised by using sodium carbonate instead of sodium chloride. This would avoid production of chlorine gas. Biscuittin (talk) 00:32, 2 November 2009 (UTC)

Sounds plausible, would it produce "suds" when water heated? The production of chlorine gas wasn't such an issue, as large vats tended to be used outdoors, at least when used as load banks by thee rail industry. Suckindiesel (talk) 15:58, 2 November 2009 (UTC)

This reference [1] states "Washing soda is often a convenient substance to use instead of salt". However, the author was using much smaller currents. Biscuittin (talk) 17:55, 2 November 2009 (UTC)

wouldn't a water resistor just produce the same effects of Electrolysis? (Oxygen and Hydrogen) --Logicwax (talk) 20:14, 6 May 2010 (UTC)

Generally used on AC, not DC, so electrolysis should not have been a huge problem. I have no hands-on experience, but there must be some gassing. I worked with an electrical foreman who in his apprentice days was tasked with dumping a bucket of seawater into some rheostats. --Wtshymanski (talk) 20:55, 6 May 2010 (UTC)

Name

Is/was the name "Salt water rheostat" in general use in the engineering industry? I am familiar with these as laboratory instruments but they were usually called "Liquid rheostats". Biscuittin (talk) 08:59, 2 November 2009 (UTC)

The term wasn't used in rail applications as far as I remember, but that was a very long time ago. Suckindiesel (talk) 15:59, 2 November 2009 (UTC)

Thank you. Would you object if I re-named the article Liquid rheostat? Biscuittin (talk) 17:49, 2 November 2009 (UTC)

Not at all, probably more apt, particularly if washing soda can also be used. I suspect every user had their own name, we called them "tubs", as in tubs of water. Relatively simple to make up on site & a lot cheaper than their later resistive grid type replacements. Suckindiesel (talk) 23:00, 2 November 2009 (UTC)

Thank you, I have re-named it. Biscuittin (talk) 23:10, 2 November 2009 (UTC)

Uses

Although used, historically, as a simple load bank, current uses include speed control of wound rotor 3-phase motors. Suckindiesel (talk) 23:17, 2 November 2009 (UTC)

Yes, they were also used on some Kando electric locomotives. Biscuittin (talk) 19:08, 3 November 2009 (UTC)

'Rapid starting cadenza'?

What is a rapid starting cadenza? Can't find it anywhere. I would discourage using overly flowery language that only confuses the reader. 173.164.209.28 (talk) 18:51, 16 December 2019 (UTC)