I am looking to install an hour meter to my new compressor. The meter is 120v-240v, has terminals for + and -. The compressor has a pressure switch, not a mag starter. Can I just connect the + terminal to one of the hot terminals on the motor side of the pressure switch and the - to ground? this seems the best and easiest way to connect.
hour meter on compressor
- Thread starter Doc1976
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American Locomotive
Well-known member
Are you sure it's an AC hour meter? +/- would be a little unusual for a device designed for AC power.
+ would go to the hot leg, - would go to neutral, assuming it's an AC meter
matt_i
Well-known member
Hour meter would wire in parallel with the motor. The + and - should not matter if AC powered as several mentioned above.
sberry
Banned
Now there is current flow on a wire designed to have none but for a fault. Secondly have likely added a device with wire way too small for the circuit it has been added to.
The 3 rd to some extent is "why" and that's not to be smart but it's not all that useful in this app. Just more stuff.
The 3 rd to some extent is "why" and that's not to be smart but it's not all that useful in this app. Just more stuff.
engineer2
Well-known member
Simply connect the hour meter wires to the wires inside the motor. see the red terminal connectors
I put a J-box behind the hour meter to avoid exposed wires.
Butchered the meter opening paint a bit because I was hand holding the jig saw.
I put a J-box behind the hour meter to avoid exposed wires.
Butchered the meter opening paint a bit because I was hand holding the jig saw.
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Many air compressor manufacturers set their maintenance schedule by hours run, hence adding the hour meter. Secondly, I will use the appropriate size wire for the load of the meter. Third, the compressor is pre-wired to the pressure switch with 2 hot leads and a ground, there is nothing to attach a neutral to.
American Locomotive
Well-known member
To be fully kosher, the wires feeding the meter should be on a small-value fuse, since if the meter shorts internally, the wires could overheat.
engineer2
Well-known member
True, to follow electrical safety rules. Chinese hour meter could short out, but hopefully internal parts will sacrifice themselves first.
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sberry
Banned
Yes, I believe that's what I meant, if one connects the meter to ground now we have a current conductor on it. The reason I am curious here is I always wonder what/how much people think it will be used and what the maintenance might be?
For all practical purposes this can be simply guessed at,,,, hence no meter comes on the machine.
Personally would fill them with synth comp oil and change it out if it broke or the oil became milky for some reason.
Maybe you will run yours hundreds of hours in a year, maybe not. Many can run decades before they need service with modern oil.
American Locomotive
Well-known member
It can be useful if you want to establish regular tank draining internals, filter cleanings, draining of the water/air separators, etc...
sberry
Banned
I kick the train valve open on occasion, usually when I see a thread about a buggered auto drain, ha.
I change my oil every 10 years, got a filter I never changed, got 2 other comps I never serviced, have them 20 yrs. Never will in my lifetime.
My bud was auto mechanic, bought a nice used Sears 2 stage 80 gal for 400. I fixed the motor starter 4 or 5 years in, he changed oil once in the 30 years he ran it every,,,, every day. Tightened the belt a time or 2.
I change my oil every 10 years, got a filter I never changed, got 2 other comps I never serviced, have them 20 yrs. Never will in my lifetime.
My bud was auto mechanic, bought a nice used Sears 2 stage 80 gal for 400. I fixed the motor starter 4 or 5 years in, he changed oil once in the 30 years he ran it every,,,, every day. Tightened the belt a time or 2.
sberry
Banned
With modern oil and anywhere not a dusty body shop oil can be good for the life of the unit. I think needing a belt tight motivated my last change. Had it out to repair the motor 3 yrs ago, didnt change.
My neighbor is a comp mechanic for Shell, got stainless pipe, the best you can get, free oil, doesn't bother doing it on routine basis.
Reason I say this isn't to get people tonight it but to understand actual demand. It's one of those things you could fuss over every day and it might last 5 minutes longer over a career.
Different matter if it's getting water, something wrong, outside seasonally needs more. Warm dry shop not so much. Mine runs a fair amount but never too hot or cold, almost no real dust.
My neighbor is a comp mechanic for Shell, got stainless pipe, the best you can get, free oil, doesn't bother doing it on routine basis.
Reason I say this isn't to get people tonight it but to understand actual demand. It's one of those things you could fuss over every day and it might last 5 minutes longer over a career.
Different matter if it's getting water, something wrong, outside seasonally needs more. Warm dry shop not so much. Mine runs a fair amount but never too hot or cold, almost no real dust.
Okay, I see what you mean about not using the ground. So if this meter is rated for 240 can I just connect each lead of the meter to each hot lead of the pressure switch?
I wired mine
110v to each terminal
(220v line in)
Motor side of switch.
Reason WHY I installed it?
Because I felt like it.
Sent from my iPhone using Tapatalk Pro
thank you for this, sounds like you have offered me a solution. avoids energizing the ground and gets the meter monitoring hours. this is the meter I got, I'm sure its a cheap one, hopefully it will last for me.
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Yep
Looks pretty much the same as mine.
I got the wiring information on this forum.
I wanted the hour meter just for my own curiosity
Because my last compressor was almost 20 years old and I really had no idea how many hours were on the thing.
Sent from my iPhone using Tapatalk Pro
Looks pretty much the same as mine.
I got the wiring information on this forum.
I wanted the hour meter just for my own curiosity
Because my last compressor was almost 20 years old and I really had no idea how many hours were on the thing.
Sent from my iPhone using Tapatalk Pro
Did you fuse either of the wires? I'm thinking without a ground fuses may be smart
Since it has spade connectors, use wires sized for the breaker, likely 12awg and yellow connectors.
I ran no fuses.
Just out of curiosity why would I want to run 12g wire on a meter that pulls less than 1 amp?
If for some reason there was an electrical fault in the meter, the circuit breaker would open before the wires could overheat. Running wires sized to handle the current eliminates any need for a fuse, and you have less parts. I'm assuming you aren't putting the meter across the room so the cost is probably less than any fuse holder you were thinking of getting.
that makes sense. Although, I'm not sure I have enough room in the pressure switch for two more 12g wires and I don't want to wire directly to the motor.
I don't know all the details of what you have to work with, or where you are mounting the meter. At the motor seems like you'd have the most room to work with on most compressors for both wiring and mounting, as the other posters did. But you can make it work any way that is electrically equivalent, with varying degrees of safety.
sberry
Banned
I agree you should do this if you want to, absolutely. But the reason I lobby my position is that its something I thought would be a good idea when I was 25, might even have thought I needed it and they obviously should have known better and put on the machine when it was built.
On expensive machines it may be easy and tracking maintenance, depreciation, like a car odometer is a factor.
On expensive machines it may be easy and tracking maintenance, depreciation, like a car odometer is a factor.
redmondjp
Well-known member
Here's another option - a battery-powered hourmeter that senses vibration. The built-in lithium battery will last for years. Here's one:
http://www.enmco.com/new/t56-vibration-activated.php
No wiring required! And it won't short out or burn down your shop either.
http://www.enmco.com/new/t56-vibration-activated.php
No wiring required! And it won't short out or burn down your shop either.
pcmeiners
Well-known member
$61.00, no thanks, I stick with my Chinese $5 meter. More important then an hour meter is a voltage/amperage meter. Just a glance can tell a lot about a running motor.
Okay, so how many people have installed an hour meter and had it burn their shop down? Or even catch fire, or damage their machine? I guess this meter is a bad idea, and should be avoided at all costs. And to all if you who go YEARS without changing compressor oil, I wonder how your trucks run?
redmondjp
Well-known member
Dude, try self-medicating with a nice infused brownie or something!
I design wiring for a living. You could easily have a 16 gauge control wire glowing red hot on a 30A compressor circuit w/o tripping the circuit breaker. Properly installed, the risk is minimal. But after the stuff I've seen out in the wild, I'll assume the worst.
For those who don't want to open up the electrical box and modify factory-installed, UL-approved wiring, the vibration-sensing hourmeter is one option.
And I have a 25-year-old air compressor that I bought new in 1990. How many times have I changed the oil in it? Once, about 15 years ago. It's still running just fine. No hourmeter either.
American Locomotive
Well-known member
Where in the world are you getting this from?
People are just suggesting that if you use an hour meter, it's a good idea to fuse the wires unless you plan on running whatever gauge wires feed the compressor itself, to the hour meter. You'll probably be fine without it, but extra safety never hurts.I personally like hour meters for keeping tracking maintenance, but at the same time I understand where sberry is coming from. I've seen Quincy piston compressors with over 1,000 hour oil change intervals. For the average garage tinkerer who's compressor might run an hour a week - that's over 19 years of service before the machine needs its first oil change. If your compressor lives an an unconditioned space where it can get really cold/humid/wet - then it'd probably make sense to change the oil regularly.
I am just amazed that people would go so long between oil changes. even on compressors that are not used much, there is still condensation that will accumulate in the crankcase throughout the year. Oil change regularity should be taken seriously. I have just replaced a 30 year old Campbell Hausfeld compressor that I used the **** out of for most of those 30 years. Still ran great, due to regular oil changes. Now, Oil change intervals really were not the topic of my post, Proper wiring of an hour meter was. My comments were in reaction to those offering that it was unnecessary or possibly a fire hazard if not wired correctly, hence the start of the post. So my last comment, with the obvious lack of concern for proper care and maintenance of some from my internet searches, was about how many people have had their meters cause a fire or other damage. If these things are not possible to wire without danger, then I wont be installing it. If it as simple as using heavy gauge wire and fusing the leads, to be safe then that's good to. I do appreciate everyone's help and input, but the "you don't need no meter, and forget about changing that oil for a couple decades" responses really aren't helpful or even correct. Try filing a warranty claim after 2-1/2 years or without an oil change and see how well that works. I also certainly would not want to be the recipient of that used compressor that was not maintained throughout its life. I take pride in keeping my equipment in the best condition I can so it lasts, and so the next guy will be able to get a long life out of it too.
sberry
Banned
I will agree the risk of fire from it is rare, part of what makes it so is correct wiring. We are not ignoring maintenance, it is our strong suit. We are simply realists about when it's required for different kinds of equipment. Stuff that gets water in it I am fussy and often try to correct. I had to reman a gearbox from something i bought, we actually added a drain, its was a problem and would have had to do it again had we not been able to change the oil which I do after I am finished with it.
sberry
Banned
Yes, you can do this. Ideally you would use heavy enough wire for short circuit interuption for the size ciircuit it is on. It should be as big as any other control wire on the machine. But, 14 for 30A, 12 for up to 50, 10 for 60, 8 for 100.
You could fuse this too, 2 of them, large wire to them and small after. Air comps are a bit funny as they don't all come cord and plug the way many other machines do, machines that may not have additional internal protection for all components and rely on the circuit breaker being correct. This may be dictated by plug and recept size.
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sberry
Banned
We did some engine oil samples to get some baseline. Modern oil is a thing of beauty, some we simply changed 3x a year and found out we can really change every 3 years as part of it is that the oil is multiple times better than when they designed the machine. I almost never shut something down for oil but do it when it's in for other work if it needs it.
We got people never change small engine oil. I do,,, some. I don't have a real shedule but if we run the snot out of it or has been a while I got no problem with dumping some fresh in.
We got people never change small engine oil. I do,,, some. I don't have a real shedule but if we run the snot out of it or has been a while I got no problem with dumping some fresh in.
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So with the fuses, I would imagine something fairly small? the meter can't pull much of anything as far as current, so maybe 5amp? I really would like to use the meter just to add a little reassurance to know exactly how much run time I've got on it but I need to be sure I've got it installed right.
sberry
Banned
Amp fuse, the meter draws a watt or 2 I think. You don't really need to fuse but simply use large enough wire. I am not really sure how factory does this, I can't recall as it's been a while since I run across a machine of this nature with a meter. Someone here probably knows, the internals of the meter would either short or blow open? What size breaker goes to this?
American Locomotive
Well-known member
Your car engine needs regular oil changes because it has combustion byproducts in the oil. The oil fills up with soot/carbon, compounds created from combustion create acids and other chemicals that break the oil down, and the high forces involved shear the oil rapidly. A normal piston compressor doesn't have any of that. In a heated garage, a compressor that sees an hour or two of use per week can literally go decades without needing an oil change.
engineer2
Well-known member
If you regularly use your compressor for high-consumption tasks such as sandblasting or an RO air sander, you can push the duty cycle limits and will need to keep an eye on oil level, cleanliness, and watch for carbon build-up in the head from normal blowby.