Wiring hour meter into new air compressor

[Jay_Hanig]

I just got a new North Star 60 gallon compressor which is listed as using 230V single phase power. I wanted to add a Hobbs meter to it for keeping up with time between oil changes, etc. I acquired a Searon guage towards that end. The gauge has two contacts on its back; neither is marked for polarity (which shouldn't be a factor anyway).

Yesterday I got the compressor running. It's hooked up to a 20 amp circuit with 10 gauge stranded wire. I broke it in and then tried some sandblasting. Sweet. Today I tried to hook up the gauge by tying in at the same place where I ran the compressor's power supply, in the pressure switch box.

I did my due dilligence and looked around the internet for wiring examples. I have to say I'm jealous of the wide open spaces in all the examples I saw because mine is tight.

From the back of the meter, I ran one lead to one leg of the motor side of the compressor and the other lead to the ground. It didn't work. Testing with a VOM, I had 3.5 volts AC across the two contacts on the back of the meter. The compressor ran fine; just no Hobbs.

So I looked a little further and decided to hook it directly to the motor. I removed the cover plate at the bottom of the motor where the wiring from the pressure switch comes into the motor and once again hooked up to one leg and the ground. When the compressor is running, I still get only 3.5 volts AC.

I would try to take pictures but it's so tight I don't think you'd see anything.

Does anybody have a clue what's happening? The compressor runs fine, no wires get hot; neither the power nor just the little ones going to the meter. No smoke or odor at all. And no Hobbs.

 

[Dingleburry]

Is the hour meter a 230 volt model, itll need both hots if thats the case.. and no polarity dosent matter

 

[Jay_Hanig]

Is the hour meter a 230 volt model, itll need both hots if thats the case.. and no polarity dosent matter

Here's the hype on the gauge from Amazon: "SEARON Quartz Hour Meter AC 110V 120V 220V 230V".

I would think since it supposedly works on 110/120 it ought to work for me. Are you saying I should hook one meter terminal to one hot leg and the other terminal to the second hot? Don't use the ground?

You have to be precise with me. I was dropped on my head multiple times as a child and I'm a little slow! I absolutely don't want to fail the smoke test.

 

[sberry]

Operating parts of circuits are not connected to ground. Second, if it is for 230v why would you try to wire it to 120? 3rd. Ask why they dont come with them?

 

[Jay_Hanig]

I want to thank you guys for putting on the right path. Putting the gauge leads to each hot leg gave me 245 volts AC across the gauge. The Hobbs has come to life! No smoke, thrown breakers, or visits from the Fire Department! Life is good.

As for why didn't the compressor come with a Hobbs meter installed? I assume it was simple economics. I got this 3 HP 60 gallon compressor for right at $550 delivered.

 

[sberry]

If it was installed inside in a decent environment would run it a few minutes with dino oil to flush the crank from manufacturing and then put Amsoil in the thing for the life of the unit or until it needed work for some reason. Measure the belts and touch the tension after this break in maybe.

 

[Jay_Hanig]

I've got it in my attached garage. It came with a synthetic oil already in it. How much time should I run it on that until I change it to Amsoil? Go ahead and swap it out now?

 

[sberry]

If it came synthetic run it a couple of years if you want. The main reason to change it out is simply to rinse out any shavings from the manufacturing. The new oils are now good for the life of the unit. It's not the same as a gas engine. While the manufacturer does list change it's really long and for their protection.
There are others besides Amsoil, it happens to be on the shelf here. Mine is used daily, I changed at 10 years last time, it's been in well over 5 again and didnt even bother last time i had it out for a repair.