Digital RPM Reader

BonnySlope

New member

Equipment
Kubota B5100DT B211 Loader, Mitchell RC40 Rotary mower, Titan 48" Box scraper
Apr 11, 2021
28
4
3
NW Oregon
Installed Runleader Rotating shaft hour meter Tachometer (Runleader RL-HM019C) it's reading RPM's and that's all I need it for. The problem I'm having it's displaying to high rpm excess, full throttle 7500 and start up 2800. Trying to go through Amazon to chat with sell Runleader for troubleshooting. Before the instruction sheet got washed :rolleyes:Oops I read most of, Max distance setting 5mm (.19)I'm was set at .12 when I got high readings. ,turning unit off (hold) and how it will automatic sense and display RPM or you can toggle threw and get max reading (rpm 2) along with svc(service time), hours and a few others you just have to toggle through and like mention true RPM will display auto.
I just don't recall a trouble shooting session and on Runleader website they have a downloadable instruction sheet BUT it doesn't work:cry:. The reason I post this is because a couple reviewer said they have used and working fine one was Kubota tractor and the other was just Kubota engine driving chipper. Have a bracket attached to generator with magnet epoxied to housing Wondering if that may cause interference? but it's reading steady just high. Only other place would be crank pully face and pick up not long enough.
I moved the pickup to about .09 but Haven't had a chance to see if improves reading.
 

Dave_eng

Well-known member
Lifetime Member

Equipment
M7040, Nuffield 465
Oct 6, 2012
4,075
391
83
Williamstown Ontario Canada
Installed Runleader Rotating shaft hour meter Tachometer (Runleader RL-HM019C) it's reading RPM's and that's all I need it for. The problem I'm having it's displaying to high rpm excess, full throttle 7500 and start up 2800. Trying to go through Amazon to chat with sell Runleader for troubleshooting. Before the instruction sheet got washed :rolleyes:Oops I read most of, Max distance setting 5mm (.19)I'm was set at .12 when I got high readings. ,turning unit off (hold) and how it will automatic sense and display RPM or you can toggle threw and get max reading (rpm 2) along with svc(service time), hours and a few others you just have to toggle through and like mention true RPM will display auto.
I just don't recall a trouble shooting session and on Runleader website they have a downloadable instruction sheet BUT it doesn't work:cry:. The reason I post this is because a couple reviewer said they have used and working fine one was Kubota tractor and the other was just Kubota engine driving chipper. Have a bracket attached to generator with magnet epoxied to housing Wondering if that may cause interference? but it's reading steady just high. Only other place would be crank pully face and pick up not long enough.
I moved the pickup to about .09 but Haven't had a chance to see if improves reading.
I find your story a little confusing.

Are you talking about a B5100 farm tractor and its generator having a magnet fastened to the generator to provide pulses?

That tractor would have a dynamo, a crude form of AC power generation. the dynamo will be turning much faster that the crankshaft speed which is what I think you are interested in. Compare the size of the V belt pulley on the end of the engine crankshaft to the pulley on the dynamo. I would guess a ratio of three to one. i.e. Engine at 2,000 rpm, your meter shows 3 x 2,000 or 6,000 rpm

Dave
 

BonnySlope

New member

Equipment
Kubota B5100DT B211 Loader, Mitchell RC40 Rotary mower, Titan 48" Box scraper
Apr 11, 2021
28
4
3
NW Oregon
I find your story a little confusing.

Are you talking about a B5100 farm tractor and its generator having a magnet fastened to the generator to provide pulses?

That tractor would have a dynamo, a crude form of AC power generation. the dynamo will be turning much faster that the crankshaft speed which is what I think you are interested in. Compare the size of the V belt pulley on the end of the engine crankshaft to the pulley on the dynamo. I would guess a ratio of three to one. i.e. Engine at 2,000 rpm, your meter shows 3 x 2,000 or 6,000 rpm

Dave
Yes I am referring to the dynamo, I understand a hybrid gen that convert to AC. The magnet is attached to rotating Dynamo housing about a .25 away from dynamo mounting point. So fairly close in diameter and rotating same speed.
Yes crank would be ideal and I may have to go there because that is the true engine RPM . The other thing I was thinking of what happens when the Dynamo need service.
 
Last edited:

BonnySlope

New member

Equipment
Kubota B5100DT B211 Loader, Mitchell RC40 Rotary mower, Titan 48" Box scraper
Apr 11, 2021
28
4
3
NW Oregon
Dave_eng, I've ran across and mounted other instrument's that read off a interrupted signal or magnet with a calibration to them but in this case you get what you pay for...simple and no adjusting. this is only a 23 dollar unit which I got half off because of credits
Thanks for your input.
 

Dave_eng

Well-known member
Lifetime Member

Equipment
M7040, Nuffield 465
Oct 6, 2012
4,075
391
83
Williamstown Ontario Canada
Dave_eng, I've ran across and mounted other instrument's that read off a interrupted signal or magnet with a calibration to them but in this case you get what you pay for...simple and no adjusting. this is only a 23 dollar unit which I got half off because of credits
Thanks for your input.
To reassure you, dynamos are about the most reliable part of your tractor. Failure almost never.

Dave
 

BonnySlope

New member

Equipment
Kubota B5100DT B211 Loader, Mitchell RC40 Rotary mower, Titan 48" Box scraper
Apr 11, 2021
28
4
3
NW Oregon
so in your experience they rarely fail? good to know.
 

Dave_eng

Well-known member
Lifetime Member

Equipment
M7040, Nuffield 465
Oct 6, 2012
4,075
391
83
Williamstown Ontario Canada
so in your experience they rarely fail? good to know.
Lots of stories of owners changing them because they do not know how to test them They look for a direct current output voltage. The dynamo produces AC voltage and then the conversion to DC takes place in the regulator/rectifier.

Dave