Recent Posts

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Changfa Engines / Re: jiang dong R108d flange/pulley
« Last post by glort on February 06, 2019, 09:36:45 PM »

Exactly what I had made up... only without the raised section to clear the crank nut.  :embarassed:

Looks exactly what I need. I'll have to try and convert measurements to see if they would fit.  Exchange rate and ridiculous US shipping charges would make one a $200 Proposition no doubt. 
Getting one made here.....  who knows.

They look beautifully made though and real work of engineering art.  More to those than meets the eye.
Generators / Re: 4.5kva output
« Last post by glort on February 06, 2019, 09:20:24 PM »

An AM radio with loud static between stations is an effective ''poor man's near field sniffer'' for checking home power EMI.

You have mentioned this before and I have been keeping an eye out to get a little transistor radio for this purpose but the things have become rare as hens teeth now. I saw a new one at an electronics store recently but it was clearly marked Digital and the was writing on the box indicating the digital circuitry made it much clearer and eliminated static. Apart from that the price was $100 which I couldn't believe for a little mono radio. I wondered who would want one now and Imagines an old bloke listening o the races or something but couldn't imagine  them paying exactly $100 for a little pocket radio.

I always keep a look out at markets etc but the only ones I have seen in the very few  did not look like they were capable of making a sound, static or otherwise. Why people would even offer busted radios I don't know but considering the other complete rubbish on offer.... 

I remember buying my grandmother a little transistor radio for Christmas. I think it cost me about $2 which was then for me a months pocket money. She sure got her moneys worth out of it though. Every morning she would sit and have her breakfast and listen to the news and talk back.  That little radio literally outlasted her and was going for years.  I'd love to be able to go back in time to that shop I bought it from. Was a dept store that sold practical things and I spent a lot of time in there with my mother and grandmother then later on wandering around myself. going to their large cafeteria  was always a treat as was getting a drink from the swirly machine up the front of Pineapple crush.  It was next to the hot roast chickens they would pull off the rotisserie for you and they did beautiful baked potatoes  and Boiled veggies.  You could get a real meal take away and even my grandmother thought they were cheap and good food.

Think I'll always feel I was born a couple of generations too late.

Generators / Re: 4.5kva output
« Last post by BruceM on February 06, 2019, 04:17:02 PM »
Shitty switching supplies are the cause of much home power EMI.  There is no regulation of appliance emissions, and often the home wiring is a strong broadband radio transmitter for something as idiotic as a washing machine that is "off", or a cheap china battery charger left plugged in.  Or a new fancy digitalized heat pump system, etc., etc.  I think it's a foolish way to spend down your health.  It was idiotic to wrap ourselves in the unshielded power cables of our homes, but that is what we've done.

FYI-  Hackaday did a tear down on three LED bulbs.

The GE Basic and Classic bulbs have no switching supply, just bridge rectify the mains to an electrolytic capacitor, with a linear current regulator to the leds in series.  The results of this design-  fairly low EMI, just the emissions of the unsnubbed bridge diodes at 50ma of current.  It could be a Lister flicker problem if your voltage dips too much on the compression stroke, but it's likely OK for SOM's or those with AVRs.

The Cree bulb they tore down has a crappy little switching power supply, so lots of EMI but likely no Lister Flicker. 

An AM radio with loud static between stations is an effective ''poor man's near field sniffer'' for checking home power EMI.  The AM band is in the range of typical switching EMI harmonics.  If your home wiring is affecting much of the AM band, over 2 feet from the wires, you've got a serious problem that should be addressed.  Common mode chokes or other suitable commercial passive filters are one cheap and simple fix, that go between the offending equipment and the outlet. Those without a digital meter can quickly isolate problems by listening to the AM radio at the main power panel as you switch breakers off.  With a digital or smart meter, you can't do that as easily since the meter itself often has a laughably bad switching supply without any filtration at all; the power company doesn't have to meet any emissions specs, so dollar was saved.

Most computer switching supplies will at least meet conducted emissions standards, though that isn't saying much.  Appliances aren't regulated for conducted emissions, so anything goes.


Changfa Engines / Re: jiang dong R108d flange/pulley
« Last post by veggie on February 06, 2019, 04:16:20 PM »
Does this size and bolt pattern fit your engine?
I have 2 for sale.
You can mount a standard pulley of any size to get the correct drive speeds.


Look here... in our "for sale" section
Petteroids / Re: PETTER - PAZ1 - New project
« Last post by sirpedrosa on February 06, 2019, 10:05:06 AM »
Hi Everyone

Just updating the hidr. press task...

Have a nice day.
Generators / Re: 4.5kva output
« Last post by glort on February 06, 2019, 09:21:47 AM »

Only when using shitty switching power supplies

You REALLY don't like switching power supplies do you Bruce?  :laugh:

I have a whole largish box of the things from different equipment that's come and gone. They do come in useful for some projects.

.1 would be a pretty low power factor but that is exactly how I have seen it stamped on nameplates more than once.
Generators / Re: Brush Wiring Diagram E9840322
« Last post by SimonC on February 06, 2019, 09:05:19 AM »
Thanks for the quick reply Bob and for the help with pictures (I was trying to follow the instructions regarding the gallery). I have attached some photos of the slip rings and rectifiers - the engine is manual start only - no battery. The output is switched either 115VAC or 230VAC. I haven't traced the wiring yet but think the 115v side is the twin rectifier/resistor setup with the larger single resistor being on the 230V side.

Many thanks
Generators / Re: 4.5kva output
« Last post by mike90045 on February 06, 2019, 07:01:52 AM »
And remember, that big old robust gear was built when a half gallon was 64 oz, not 60 oz like nowdays.

Generators / Re: 4.5kva output
« Last post by BruceM on February 06, 2019, 02:26:57 AM »
VA and watts the same at a PF of 1, which is what it's rated for, not 0.1. 

For linear loads like resistive heaters and such, Watts and VA are the same.  Only when using shitty switching power supplies and lots of crappy low PF light bulbs will you see a big difference, though induction motors aren't so hot sometimes either and could use some more capacitance in parallel to reduce the VA.  Simple enough, just monitor V and A and add caps to minimize the total V times A.  It's very worthwhile to reduce often run motor VA for inverters- they do draw real PV or battery power to generate every VA, real or reactive.  I've confirmed that with a design engineer at Magnum and also myself on my own inverter design.  For motor generators, bad PF loads only cost you 15% more in fuel, but mostly it just eats your total capacity and motor starting capacity. 
Generators / Re: 4.5kva output
« Last post by listeroil on February 05, 2019, 11:56:26 PM »
Heres a picture
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