Hi Russell,

Use a cheap UPS? May have better regulation (repeat, may). Your 
generator, if it's the same one I'm thinking of, I think also has a 12VDC 
output, use it to charge the battery in the UPS. 425VA UPS is around 
US$67, or 660VA around US$76. Have thought of the same idea for keeping 
my UPS/PC running during longer power outages.

Brent

> I can and will try this for myself but, as I need the result in 48 
> hours time I'll also ask here. Someone should have invented this wheel 
> already.
> 
> I have an exceedingly cheap and cheerful petrol motor powered 
> alternator rated at about 700 watts max. (Cost about $US65 new).
> 
> Voltage stability at constant load is "OK" but if you step-change the 
> load it surges extremely badly. Variation is enough for incandescent 
> bulbs to dim badly and/or get VERY bright for a second or so. I 
> measured the surges a while ago but don't recall the results - very 
> nasty is enough to know. Some loads don't mind this while others would 
> die.
> 
> I need to run a PA system and bass guitar amplifier for a concert 48 
> hours from now. Required wattage is liable to be under 100 watts.
> 
> I could:
> 
> 1 - Pray
> 
> 2 - Add a large swamping load first and try to ensure nobody step 
> changes the load.
> 
> 3 - Add a manually multi step switched load and use this to phase in 
> and out real loads. Actually quite easy to do.
> 
> 4 - Make an electronic stabiliser - eg smoothly winds in a large 
> resistive load, then step adds true load and matches it by dropping 
> off resistance and then slowly winds off most of the DC load. Could do 
> this only when load is added or removed at known points or leave some 
> resistor load in to allow auto action to handle step changes along the 
> way.
> 
> 5 - Add a "spinner" - an unloaded motor which acts as a rotary 
> capacitor.
> 
> 6.    Use a DC/AC converter - with a lead acid battery charged by the 
> alternator (if needed)
> 
> 7- Some combination (especially 1 :-) ).
> 
> ______
> 
> 1.    On an 'as required' basis.
> 2.    Should be effective with vigilance.
> 3.    Is easyish and effectiveish.
> 4.    is not hard and arguably the best long term solution BUT there's 
> too much else to do unless it's essential to do it this way,.
> 5    I'm not sure how well this works on 1 phase due to the quasi 
> rotating field compared with 3 phase.
> 6    Cheating. Probably easiest at the power level concerned.
> 
> Thoughts ?
> 
> 
>         Russell McMahon
> 
> 
> 
> -- 
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
> 

-- 
Brent Brown, Electronic Design Solutions
16 English Street, Hamilton 2001, New Zealand
Ph: +64 7 849 0069
Fax: +64 7 849 0071
Cell/txt: 027 433 4069
eMail:  brent.brown@clear.net.nz


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist