ST Head Waveform Regulation

[Tom Reed]

Well on an ST5 1500 watts is a pretty good percentage of the 2500 watt per leg output. I've seen as much as a 20 volt difference between legs. I've got a load balancing transformer sitting in the engine shed, guess I should try hooking it up some time and see how well it works.

[cujet]

We just tried 2000mF on the rectifier output on a friends ST-5 6/1 setup. The pocket O-scope (fleabay special) clearly shows a nasty rectifier output. 1000mF was sufficient to smooth the ripple out to DC, so we installed 2ea. 1000mF caps in parallel.

The bottom line: The ST-5 output sine wave form is nasty. It cleans up by some small amount under a 3000 watt resistive load. The caps "might" help the 115V output wave form some, but it is not significant. I'm fairly sure that there was some sort of difference between the caps "not connected" and "connected". But it was so small compared to the wave form distortion, I'm not sure it matters.

[Horsepoor]

I am the "other friend Chris has" and I just finished experimenting on my ST 15 gen head loaded at 40 amp and 230 VAC. Ended up with 8000 uF which raised my output ST voltage to 238 VAC and a better overall wave form. I am pleased with the results for what it is.

Another benefit is an increase in voltage. My ST VAC  was always a little low. Now the AVR has something to regulate and I can, if desired, adjust it down some. Here are some crude photos using my $5 volt meter and $75 pocket O-Scope, nothing but the best for my ST & listeroid. Also, ignor the units on the O-Scope, I am still learning how to use the device but the wave form is valid.

[cujet]

Hey Horsepoor,

I only have 2 friends! 

Is the pic above before or after? And, do you have before/after pics?

Also, what was the load?

Chris

[Horsepoor]

Chris,

Only two friends who will admit they know you ... The before O-Scope pictures were posted last week forum, look in recent posts fo the full sized O-Scope green sceen back ground with a very light load, on the ST at about 1500 warrs. I posted the worst O-Scope image we could get at that time "without" and filtering circult.

Back to current events, I didnt want to experiment on my ST system, so I talked Rocketboy into testing all this stuff on his unit with your assistance. Sorry, but I deleted the photos after posting on the forum. Overall, I dont think my wave form changed that much primarily because it wasnt that bad to begin with. I am extremely pleased with the VAC increase so that my AVR now has something to regulate. One leg of my ST 15 had a low voltage reading (109 VAC) under load up at the main house 200+ feet away which has now been corrected - happy days are here.

I realize 8,000 uF is a rather large amount of capacitance which will lag behind resulting in higher voltage after a large load has been disengaged, and a slower rise in voltage when a large load is added, but this is the way I figure it at on my ST 15 @ 230 VAC. Going from 45 Amp to 35 Amp as one air conditioner kicks off is no big deal, likewise going from 30A to 45A as the electic hot water heat kicks in should be no big deal due to relative high loads normally on the system. I hope I am correct.

Bruce

[Horsepoor]

I just installed a whole house electrical remote monitor. I highly recommend you buy one of these.

http://www.energymonitors.com/product.php?product=175282

Took every bit of 60 seconds to clamp the sensors onto the current lines, it really works well and has great range. Sitting here watching the whole house load change in real time with appliances engaging and tuning off, really cool.

Check eBay, just saw a new one for $89 plus shipping. I paid $144 but it was worth it. I can now easily monitor load from 100+ feet away. Oh, it has an adjustable alarm for load too. What a neat item.

Bruce