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My little Kohler Substation

Mike Cushway

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What is the proper way to install a vintage analog ammeter on my little 1A21? I have matching Volt and amp meters and want to mount them on the panel holding the NOS hour meter.

The installation and the ammeter in question.
 

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Vanman

Subscriber
Last Subscription Date
07/10/2019
If it doesn't require a current transformer, it would just be wired in series with either of the output lines from the set. What does it say on the back of the meter?
 

Frank DeWitt

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Last Subscription Date
12/17/2019
My guess is that the meter needs a shunt. It should say on the meter or the box or documentation with it. If it needs a shunt then the shunt is wired in series with the generator hot wire. The meter is then connected across the shunt using smaller wire. (In parallel with the shunt.) You will need to know what shunt works with this meter.
 

Vanman

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Last Subscription Date
07/10/2019
Interesting. I have not seen an AC ammeter that uses a shunt, though I don't see why it wouldn't be possible.

In my experience, smaller AC meters like this one are direct reading, and larger ones read full scale at 5 amperes, thus requiring the appropriate current transformer.
 

Zephyr7

Registered
Ive seem up to maybe 20-25 amp direct reading AC ammeters, the same for DC. I’ve only ever seen AC ammeters using current transformers (CTs) though. Every meter I’ve ever seen that uses a shunt is for DC current.

It looks like the lower left part of that meter face might have some writing. If it says something like “50mv FS”, that means 50mv will make the meter read full scale, and that would be for use with a current shunt. A meter needing a CT will say something like “5A FS” Meaning 5A to read full scale.

Bill
 
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Mike Cushway

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I should have the meter today and will inform as to what it says. I appreciate the help in building my little "substation". I am offgrid and will rely completely on this little 1a21 (soon to be 1a22) for my bi-weekly water pump and daily odd power usage. I fill a 65 gallon poly tank in the cabin for my daily water. I have a little over 2 hours on the unit now including a 40 minute run yesterday pumping water. Eventually, If I can ever find a decent old ram pump, I will create an overflow system that means my tank is always full from the spring below the cabin.

Fwiw, the 1A21 starts my 3/4hp lathe like a champ. I did not expect that!
 

Zephyr7

Registered
Looks like an inspection stamp (the circle in the middle), a serial number (longer number near the top), and a date code (maybe February of 1970). No info about ratings. What other text is on the face of the meter? Usually it will say the manufacturer, something about full scale, and sometimes something about the meter movement design.

BTW, the beefy bolts for electrical connections don’t mean anything. Even 1ma meters tend to have beefy bolts.

Bill
 

Zephyr7

Registered
Well, they sure don’t give you much info on that little meter!

You’ll probably need to measure it. The Easiest safe way is with a transformer and small incandescent light bulb. See if you can get a 10 watt 12v Low voltage light bulb (make sure it’s not an LED replacement, you need an old school “real” light bulb).

Get a 12v AC output transformer. At least 1 amp out. You used to be able to get these at rat shack, hopefully you have one handy so you won’t have to order one.

Connect the meter in series with the light bulb and power them from the transformer. 10w at 12v Is about 0.83 amps. If the meter registers a bit under 1A then you don’t need a CT — it’s a direct reading meter. If the meter shows something else, then you can work out the ratio to figure out what CT you need to read correctly.

Bill
 

J.B. Castagnos

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Last Subscription Date
01/01/2006
Just a guess, you will need to test to be sure. From the size of the studs I would say it's direct reading.
 

Mike Cushway

Registered
Is there another way to test short of just putting it inline? I dont have any of the equipment suggested.

I spent all morning cleaning up the parts that came in today. After installing the carb, fuel shutoff valve, gas valve and intake oiler, I plumbed a demand regulator and new LP line with shutoff. I opened the gas valve as described in the manual and then turned the gasoline needle off at the fuel pump. As the engine sputtered to quit, I opened the valve to the demand regulator and just like clockwork she fired right up on LP! I had to adjust the gas valve a bit to the 1200w load and it just sits there an purrs. Its been a fun journey so far. Today was very rewarding.

Does anyone have any factory paper that tells what grade oil goes in the intake oiler and what the drip rate should be? Pretty sure the residual oil in the jar had some Marvel in it. It had that same smell.
 

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Vanman

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Last Subscription Date
07/10/2019
Beautiful. You even have an original stand. I have read on here that some considered the intake oiler to be snake oil. I have no idea if that is true. Maybe they meant to put snake oil in it. :D

For the meter, hook it up in series with one of the output lines from your set and apply a 5 ampere load. If it goes full scale, you need a current transformer. If it reads 5 amperes, you're all done. If it reads something else, or goes beyond full scale, you have a screwy meter. :crazy:
 

Zephyr7

Registered
Is there another way to test short of just putting it inline? I dont have any of the equipment suggested.
You really need to put a known load on the meter and then see what it reads. If it was a DC ammeter there would be other ways to do it, but AC is trickier.

I’d use a 1A load, not 5A like vanman suggested. Most CTs are 5A out, but you have a small meter and it might go full scale with less. You don’t want to burn out your meter during your test. Best to start with a low current.

I wouldn’t be surprised if your meter is direct reading. If you don’t have the transformer and 12v light bulb, a 100 watt bulb on 120v will draw the same 0.83 amps. You could try that, but I’d try to have the meter mounted in a grounded panel just in case (probably not necessary, but being cautious doesn’t hurt).

Bill
 

Radiomike

Registered
The ammeter is probably a moving iron type as the scale looks a bit non-lnear especially at the low end. Moving Iron meters respond to DC as well as AC. So you could test it on 5A DC.

For your voltmeter you will be making connections to 120 or 240 Volt. I would recommend a fuse in the wires to the Voltmeter. A 1A fuse should be enough provided it has sufficient breaking capacity, ie rated at 240Volts AC or higher.

I would also loom the ammeter wires and voltmeter wires away from other wiring and keep the ammeter wiring separate from the voltmeter wiring. I would also use good quality crimps or lugs on the ammeter with locking nuts. Insulating caps for the studs are available but a large wire nut may work as well.

Mike
 

Mike Cushway

Registered
Confirmed as direct reading. 800w load, 125v.....6.4A

I'll readjust using a full load at whatever voltage that it pulls down to. Maybe average the difference of the two loads. My matching 0-150 voltage meter will get mounted tomorrow.
 

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Zephyr7

Registered
For your voltmeter you will be making connections to 120 or 240 Volt. I would recommend a fuse in the wires to the Voltmeter. A 1A fuse should be enough provided it has sufficient breaking capacity, ie rated at 240Volts AC or higher.
A regular 1-1/4x1/4” glass body fuse will work for this purpose since they are rated 250V.

+1 about using crimp lugs for these connections. I highly recommend the AMP PIDG terminals and the Solistrand terminals. Both are FAR superior to the hardware store terminals.

The studs on your meter are probably brass, or maybe silicon bronze (which is a coppery color). Use brass nuts on those studs. The studs are often fine pitch threads too so be sure to get the correct nuts.

Bill
 

Mike Cushway

Registered
Thanx for all the input guys! I very much appreciate the suggestions.

I will install a 4x glass fuse panel inside the breaker box tomorrow for the voltmeter and hobbs. I ran new 8ga leads from the genny to the breaker box thru the amp meter. Yes, I use quality copper crimp-on lugs anywhere possible.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Sweet!

Remember that the voltmeter will essentially read battery voltage when connected to the output of your automatic Kohler when no load is present on the line. Eventually this would discharge the battery. To avoid this, the voltmeter can be connected upstream of the Generator Relay, the center one in the controller.

For that matter, any load that you want to power whenever the set is running, but NOT have control over starting and stopping, can be connected there. :brows:
 

Zephyr7

Registered
Thanx for all the input guys! I very much appreciate the suggestions.

I will install a 4x glass fuse panel inside the breaker box tomorrow for the voltmeter and hobbs. I ran new 8ga leads from the genny to the breaker box thru the amp meter. Yes, I use quality copper crimp-on lugs anywhere possible.
Cut a piece of clear plastic (I recommend polycarbonate for this) maybe 1/16” or so thick, mount it a little bit above the fuse panel on standoffs. This is assuming open fuse holders, no need if they’re the panel-mount round insulated kind. The plastic panel might save your azz someday if something comes loose in the control compartment.

Bill
 
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