Lister Engine Forum

Lister Engines => Lister Based Generators => Topic started by: Jordan on June 23, 2019, 11:02:10 AM

Title: Alternator Hz tip
Post by: Jordan on June 23, 2019, 11:02:10 AM
I heard a suggestion for fine-setting of engine speed to obtain the required Hertz.

Assuming pulleys of theoretically near-correct ratio are installed on engine and alternator shafts:
Paint a white line on the alternator pulley, so that with a lamp shining (powered from grid, on a house circuit for example) the line will appear stationery when correct speed is achieved.
It's the same principle that was often seen on hi-fi record player turntables.
Has anyone else heard of this method?
Title: Re: Alternator Hz tip
Post by: BruceM on June 23, 2019, 04:45:52 PM
https://www.amazon.com/Neiko-20713A-Digital-Tachometer-Contact/dp/B000I5LDVC/ref=sr_1_4?keywords=rpm+meter&qid=1561304547&s=gateway&sr=8-4


Plan B

Title: Re: Alternator Hz tip
Post by: mike90045 on June 23, 2019, 11:01:55 PM
But that requires you have stable Grid power to check it with.   Which is fine if you are on grid.  I use the frequency meter on my inverter to set no-load to 63hz, and full load ends up at 58hz
Title: Re: Alternator Hz tip
Post by: BruceM on June 23, 2019, 11:16:42 PM
It's going to be difficult to use an incandescent bulb as a strobe; there is too much heat retention in the tungsten filament, even with a dark room.   Buy the tachometer.
Title: Re: Alternator Hz tip
Post by: Jordan on June 24, 2019, 01:54:21 PM
I've gotta try it, as all it needs is to paint a line on the pulley.
It would be fun if it works (maybe better under fluoro light?), and could be handy as it's always there.
I shall report!
Title: Re: Alternator Hz tip
Post by: guest23837 on June 24, 2019, 03:58:38 PM
https://www.ebay.co.uk/itm/Digital-Tachometer-Laser-Photo-Non-Contact-RPM-Tach-Meter-Motor-Speed-Gauge/323731716541?epid=9009591220&hash=item4b5fe9f9bd:g:~toAAOSwSk9chjwa

cheap and chips and fairly accurate
Title: Re: Alternator Hz tip
Post by: Jordan on June 24, 2019, 11:32:23 PM
Don't panic, folks. There needs to be a white line on the alternator pulley for my digital tacho anyway. :)
I also have a frequency meter, which will look in keeping with the old genset.

Title: Re: Alternator Hz tip
Post by: sirpedrosa on June 25, 2019, 12:53:22 AM
Hi Jordan

It's not a white line, its a refletive stripe, in order to reflect laser beam to reader.

And, yes, that digital it is fairly accurate.

BR
VP
Title: Re: Alternator Hz tip
Post by: old seagull man on June 25, 2019, 09:01:41 AM
Buy yourself one of these and connect in to the generator output.
The 20Amp version has its own internal shunt so the power go's straight through it at all times and you have volts, Freq, watts, Kwh, amps, all for less than the cost of a few beers.
Got 4 of them on things. I know Glort collects them.

https://www.ebay.com.au/itm/AC-110-250V-100A-Digital-LCD-Panel-Meter-Monitor-Power-Energy-Ammeter-Voltmeter/323753388465?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
Title: Re: Alternator Hz tip
Post by: 38ac on June 25, 2019, 11:19:50 AM
There is no doubt that your idea will work but as has been said by the others with all the cheap meters around why bother?  I have two Kill O Watt meters that I bought when they were $12.  They are $30 now but there are cheap alternatives on Ebay.   I keep one near the set and the other one is used at the house and is used to monitor loads.
Title: Re: Alternator Hz tip
Post by: Jordan on June 25, 2019, 01:04:30 PM
Here's my portable meter box, apparently made for servicing small gensets according to the leaflet that came with it.
I found it at a swap meet.
It's plugged into a house power outlet, switched on but with no load attached.
Title: Re: Alternator Hz tip
Post by: guest23837 on June 25, 2019, 10:32:10 PM

I would be measuring the frequency off the generator output.  This will take into account all variances like pulley wear and give you an absolute speed/ frequency.  Having a Multimeter fetish I know there are a load of meters available cheap as chips from China with frequency which are all amazingly accurate. You should be able to get one for $10.

The panel frequency meters aren't expensive either.
Meters are better, simpler and more accurate than anything else I can think of.

Good advice from Glort I took his advice on a multimeter 12 I think it cost and it does as much and more than my local sparks very expensive Fluke multimeter