Seat Time vs. Clock Time

   / Seat Time vs. Clock Time #1  

REDD

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Apr 12, 2004
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In another thread someone stated running the PTO at rated speed is the condition where one hour of seat time equals one hour of clock time.

I believe this goes back to something I read months ago on another forum where readers talked about the hourmeter on their tractor, and if that device really represented actual hours logged. Some readers thought its display changed proportionately based on engine speed, the thought being a tractor idling versus a tractor pulling a plow full bore through a clay field are two completely different wear patterns on a tractor, and the hourmeter should failrly represent the duty a tractor has seen. Other people thought an hour display was an actual hour passed, and that was that.

I contacted the Kubota website and asked the question if the hourmeter display relied on engine speed, or was it simply like a wall clock. The answer was it's simply a clock which runs the instant the key is turned, engine running or not.

Any comments? Are other brands different?
 
   / Seat Time vs. Clock Time #2  
If it measured what the tractor was doing it wouldn't be a "hour meter". It's just a clock that turns on everytime power is applied to it when the tractor is on. It's nothing fancy like the OLM (oil life monitor) you might find on a computerized car or truck. It would need a rather advanced computer system to calculate real work time and conditions. Temp, load, fuel used, rpm, rpm ramp rates to load, etc... It took GM almost 5 years to get their OLM system up and running.
 
   / Seat Time vs. Clock Time #3  
REDD said:
I contacted the Kubota website and asked the question if the hourmeter display relied on engine speed, or was it simply like a wall clock. The answer was it's simply a clock which runs the instant the key is turned, engine running or not.

Any comments? Are other brands different?
Kubota's answer is interesting. This has been debated on here before. It appears they are saying that an hour on the meter is equal to an hour on a clock. With my 2800, it doesn't seem to record true hour to hour unless I'm running PTO speed. I'm pretty sure that if I let it idle at 1200rpms, for 60 minutes, the time recorded on the hour meter will be much less.
 
   / Seat Time vs. Clock Time #4  
Most hr meters start running when the key is turned on AND the engine is producing oil pressure.
If not and you accidently left the key on........ouch!
If you look at the engine compartment you will see the wire running to the sensor on the motor.
Tractors used to use a cable running from the engine to the hr meter, that is when the "pto" speed comes into play most were set to click off one hr if the engine was running at PTO speed.
Some still use this method.
Idling it would take a long time to run up an hrs worth of time.

BTI
 
   / Seat Time vs. Clock Time #5  
On some tractors it's easy to tell. If the "hour meter" is part of the tach you have one that depends on the engine speed, with 1 hr at PTO speed being 1 actual running hour. If it is not part of the tach it is very likely a form of electric clock. I'll have to check but I don't think my BX has the "no oil pressure cutoff" on the hour meter.
 
   / Seat Time vs. Clock Time #6  
I don't know who you talked with at ktc, BUT, I have personally tested this on tractors with an "hourmeter"and aTractormeter. The differance is that the hourmeter is not inside the tachometer. It is an electric device that when the key is turn on, or left on after stopping, it operates as a clock recording the hours. On some smaller tractors, B7100 ect. , it will record hours even if the engine is not running. The tractormeter records at pto speed. On some of the older tractors, it states next to the hour indicator "at 540 pto". I have tested this and I hope this will answer your questions.
 
   / Seat Time vs. Clock Time #7  
I believe most of the Kubotas have hour meters that are actualy RPM counters, the faster the RPM the faster the hour meter runs.

Next time you are on the tractor take note of the time you started and finished, unless you run the entire time PTO rated speed you can tell the difference between the dash time and clock time.

Running at 2000 rpms my tractor counts one hour as .8 (8/10) of an hour. When I mow at the PTO rated speed one hour is counted as one hour.
 
   / Seat Time vs. Clock Time #8  
I concur with Mr. Big John, and disagree with Mr. Marcussen for the BX...and probably the B series. I can confirm that my BX hourmeter turns when the key is turned on whether the engine is on or not. It measures "true" hours. I learned this when I left my ignition on so I could keep the headlights on my workspace and POOF, there went an hour on my machine. I'm 100% certain, an hour in an hour without the engine turning once.

While I have no experience with larger equipment, the overwhelming opinion is that the hourmeter bases itself on a ratio of PTO speed to rated speed...running the tractor at 1100 rpm where the "rated speed" is 2200 rpm would yield 30 minutes on the hourmeter in an hour's time. At least that's my understanding.

B is probably like the BX...have no idea about the L series. Certainly the M would have a "rated" hourmeter.
 
   / Seat Time vs. Clock Time #9  
REDD, there's not too many things that I'm really sure of, but this is one of them. Kubota makes, or has made, both kinds of meters.:D So I'm surprised you got the answer you did from Kubota, unless you told them what model tractor you were inquiring about. I had a 1995 B7100 and its clock was as you described; simply a clock that ran any time the key was turned on, so if you had accidentally left the key on when the engine was not running, it would have run up time on the meter. And of course, you could turn the key off with the engine running and continue working with the tractor without adding any time to the "hour meter". Of course you would not have been charging the battery either. Fortunately, I never made either mistake. That B7100 had no tachometer. But then I traded up to a B2710 in 1999 and it had the other kind of meter, geared to the tachometer. Running the tractor at PTO speed would make it register an hour in an hours time, but running the engine at a lower rpm would make it take much longer than an hour to register an hour on the meter. I'm not sure which type other makes and models have.
 
   / Seat Time vs. Clock Time #10  
I would imagine that the new hour meters simply run of the battery and key switch as kubota stated. However, many of the older tractors, such as my Ford, have a gear driven hour meter that runs off of the the oil pump gear. These types were timed or geared such that they would accurately represent an hour at PTO speed. Ergo, the slower the RPMs of the motor, the slower the hour meter ran, and vice versa. I don't think for a moment that this had anything to do with anything other than Ford believing that PTO speed was a good average point to mark the hour on a machine.
 
 
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