Need Help for Rpm Measurement System on Threshing Machine

Thread Starter

sgagroelectronics

Joined Sep 10, 2019
4
Hello,i have a customer which has sent me a warning indicator rpm monitor but it hasn't a lcd panel only 10 bulbs with the symbol of axle/sensors.Sensors consist with one 820Ω Resistor and an reed switch in series.
The principle of work is,when the axle achieves its working rpm then the bulb turn off
The problem i have now that one bulb is glow all time. We changed sensor and We test the circuit everything is ok and secondly i don't know how the bulb goes off with the reed switch.So,i need a help from the forum
Thank you
 

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LesJones

Joined Jan 8, 2017
2,359
With the almost total lack of information you have provided about the device I SUSPECT it works by the pulses from the reed switch triggering a retriggerable monostable multivibrator. If the pulses occur more frequently than the timeout value of the multivibrator then it's output remains high. The circuit that follows will put the light on if it sees pulses on the output of the multivibrator. It could also use a frequency to voltage converter IC (Such as an LM2907.) followed by a level detector. There could be other methods used. If you trace out the schematic of the device we can confirm which method is used.

Les.
 

MisterBill2

Joined Jan 23, 2018
4,054
Given that we have NO information on this system package except for 2 pictures of the outside, there is no way we can offer anything better than a guess. It might be a wireless system, or the sensors might be wired. The description tends to point towards a fault in the display section, but we have not one word of description as to what that is. But it is not a failed indicator light bulb.
 

jpanhalt

Joined Jan 18, 2008
8,102
1) For the device numbers, we need to know the implement's manufacturer.
2) There are 8 items monitored by single bulbs, apparently. The method you describe is very common on farm implements to indicate status of conrols such as RPM, PTO, 4WD, etc. On my tractor, the light comes on when the proper RPM is reached.
3) Are you sure how the device works?
4) Are you sure one or more lights are not supposed to be one?
5) Please tell us what each symbol on the panel means.
 

MisterBill2

Joined Jan 23, 2018
4,054
The manufacturer is Jaeger, the product is a monitor system, and that is about all that we know. The symbols are icons for the various sections of a combine/thresher machine. That much is quite clear. But there is no hint about what the rest of the system is, although it is probably not very complex. If the TS can provide a circuit that would help, but I doubt that is possible. A photo of the insides of the display device could provide some indication of how it works, and possibly also reveal a broken or failed component.
 

jpanhalt

Joined Jan 18, 2008
8,102
The manufacturer is Jaeger, the product is a monitor system, and that is about all that we know. The symbols are icons for the various sections of a combine/thresher machine. That much is quite clear. But there is no hint about what the rest of the system is, although it is probably not very complex. If the TS can provide a circuit that would help, but I doubt that is possible. A photo of the insides of the display device could provide some indication of how it works, and possibly also reveal a broken or failed component.
Jaeger is a relative common company name. As for farm implements, I could not find modern ones on Google. Can you provide a link to a modern thresher made by Jaeger?

Among the "problems" raised by the TS are these:
1) "The principle of work is,when the axle achieves its working rpm then the bulb turn off"
That is possible, but is opposite the way similar indicators, such as PTO speed, usually work. Consider the effect of a faulty bulb.

2) "The problem i have now that one bulb is glow all time." That may be normal. It depends on what the bulb indicates. While one can guess at the meaning of those icons, it would seem more helpful if the specific light that stays on were identified.

My equipment is mostly CNH and Case or New Holland badged per se. JD and Mahindra are also common in my area. Jaeger may be branded on some equipment, but it is unclear to me whether Jaeger is just a brand or the physical manufacturer. Shop Service Manuals with schematics are available for most farm equipment, though there is controversy today about the "right to repair." I routinely get them for all of my equipment and consider such availability before purchase. Nevertheless, within a single manufacturer there is a lot of commonality and even across manufacturers there is some commonality. Thus, more detail than what is shown in the pictures might help us find comparable designs to review.
 

MisterBill2

Joined Jan 23, 2018
4,054
My guess is that Jaeger is the maker of that device, not the whole machine. Like "SUN" tachometers used to be. And it may be that the whole thing is in another part of the world. I agree that it makes more sense for the light to indicate that conditions are OK, but I have come across the opposite. One light switching on may get more attention than one of 8 switching off.
 

Thread Starter

sgagroelectronics

Joined Sep 10, 2019
4
The 8 way switch works as isolator for each indicator and what i mean? If an indicator is faulty illuminate you can isolate the indicator until you repair it
The system consists of two wire magnetic sensors
Components of the sensor are one 820Ω Carbon film resistor and one reed switch connected in series
How the system works
The panel has 8 indicators and 8 potentiometers
Each indicator is connected to sensor on various axles of threshing system
When the machine starts to work, rpm rise up and indicator go off.So when a drive belt fails the axle has no rpm then the corresponding indicator illuminate to warn you that this system has a problem
 

MisterBill2

Joined Jan 23, 2018
4,054
OK, now we know a bit more. For the one channel that fails to turn the light out, are the voltages at the sensor correct? Do they match the voltages of a working channel? And what procedure are you using to check it? What pulse rate are you intending to set it for?
 
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