Author Topic: Frequency/Voltage Meter for ST gensets  (Read 7408 times)

BruceM

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Frequency/Voltage Meter for ST gensets
« on: April 14, 2016, 04:12:39 PM »
I've been disappointed with the analog panel meters for AC frequency and voltage from China.  The frequency meters in particular are junk- when voltage goes down (with increased load and thus lower frequency), the frequency meters show an increase in frequency! Laughably bad design.

Many digital frequency meters have problems with the ragged waveform of the ST generator heads.  They will not display the proper value, or even close.

I did find one cheap ($10) digital meter that is quite good:

http://www.ebay.com/itm/131683950915?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Both frequency and voltage are displayed properly and accurately on an  ST-3 head on harmonic.  Voltage is RMS, tracks a Siemens ($) display within a volt.






Tom

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Re: Frequency/Voltage Meter for ST gensets
« Reply #1 on: April 14, 2016, 06:31:46 PM »
Using a similar one, only with a discrete display and it does work quite well, but according to the clock on my oven (which is frequency timed and keeps perfect time on inverter power) the meter reads a bit high. One time I did get some real random Hz numbers out of the meter, but after a restart it worked perfect.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

BruceM

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Re: Frequency/Voltage Meter for ST gensets
« Reply #2 on: April 14, 2016, 06:49:06 PM »
Thanks for the tip, Tom.  I'll double check the frequency measurement on this model via optical tach on the ST-3 pulley.

veggie

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Re: Frequency/Voltage Meter for ST gensets
« Reply #3 on: May 04, 2016, 02:58:34 PM »

I have an interest in that meter that you pointed out, but I don't understand how it calculates AMPS/WATTS without using an inductance ring?
Here is a similar listing which shows the wiring diagram.

http://www.ebay.ca/itm/Digital-Blue-LED-Power-Panel-Meter-Monitor-Power-Energy-Voltmeter-Ammeter-20A-AC-/262409140534?hash=item3d18cdb936:g:aZ0AAOSwMVFXIYT1

Does the full system current have to pass through the meter via the two terminals labeled "LOAD" ?
For example:
Would the meter be wired in series with the L1 (hot) wire of a 120 volt circuit ?
If so, I see a problem when trying to measure the output of a  230v split phase generator when only one leg of the circuit can pass through the meter.

Thoughts?

Cheers,
Veggie
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
- Changfa S195 (Waiting for a project)

carlb23

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Re: Frequency/Voltage Meter for ST gensets
« Reply #4 on: May 04, 2016, 05:24:51 PM »
I use two of these with my generator setup and they work fine.  I monitor each leg. they come with current transducers.

http://www.ebay.com/itm/LCD-AC-80-260V-0-100A-Digital-LCD-Combo-Panel-Meter-Volt-Amp-Power-module-Watt-m-/111916158145?hash=item1a0eb90cc1:g:1AMAAOSwll1WzryN

Tom

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Re: Frequency/Voltage Meter for ST gensets
« Reply #5 on: May 04, 2016, 06:36:41 PM »
Based on this photo I would say that the power does indeed pass through the unit.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

Horsepoor

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Re: Frequency/Voltage Meter for ST gensets
« Reply #6 on: May 04, 2016, 07:48:27 PM »
I have purchased most of the meters seen on the next page for various applications related to Listeroid, power cables with built in meters, ATVs, motorcycles, etc. All have worked very well. The bonus for me is the store is local so I just online order and arrange for front desk pickup.

http://www.mpja.com/Digital-Panel-Meters/products/52/

The other mail order site I use has better prices and a MUCH greater selection but a week or so wait due to shipping

http://stores.ebay.com/Asia-Engineer/Meters-/_i.html?_fsub=1043767018&_sid=149380788&_trksid=p4634.c0.m322

Bruce
GTC 20/2 down rated to 850 rpm - ST 15
Metro 6/1 800 rpm on cart - ST 7.5

BruceM

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Re: Frequency/Voltage Meter for ST gensets
« Reply #7 on: May 05, 2016, 02:46:00 AM »
Must be nice to have MPJA close by!  Good outfit.  Thanks for the meter tips!

Horsepoor

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Re: Frequency/Voltage Meter for ST gensets
« Reply #8 on: June 06, 2016, 05:46:27 PM »
MPJA (online mail order company in Florida) just placed this multi function meter on sale for $18.70. I post this for review because if I had it to do over again, I would not use the large analog gages to monitor each function and then install a switch to flip between line Line 1 and Line 2. I would just buy two of these meters, one for each line, and be done.

http://www.mpja.com/06-06-16.asp?r=303222&s=1
GTC 20/2 down rated to 850 rpm - ST 15
Metro 6/1 800 rpm on cart - ST 7.5

buickanddeere

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Re: Frequency/Voltage Meter for ST gensets
« Reply #9 on: June 07, 2016, 02:44:28 PM »
Based on this photo I would say that the power does indeed pass through the unit.


How is it we have an energized male plug ?