Motor speed detect sensor

Hi,

I am using a motor that spins at 6000 rpm.

I would like to connect a sensor to the shaft of the motor to test the speed of the motor .

The output of the sensor can be analog or digital.

Low cost sensors that I have seen is capable of measuring only upto 5000rpm.

Can any one please suggest me a sensor module that can perform my requirement.

The working voltage of the sensor. can be upto 24V.

I know i can measure the rpm by using the back emf but I need to measure using the sensor and compare the value with the back emf value.

Thanks.

https://www.walmart.com/ip/Digital-...online&wl12=351242665&wl13=&veh=sem#read-more

Range: 2.5 to 99,999 RPM

Hi

I am looking for something like this

https://www.electroschematics.com/12275/motor-speed-sensor-module-circuit/.

What I am not sure is , upto what rpm can this measure ?

Hi,

from the RC it should be able to measure RPM up to 30,000. or sth in this range.

Klaus

vikash23 said:

Hi

I am looking for something like this

https://www.electroschematics.com/12275/motor-speed-sensor-module-circuit/.

What I am not sure is , upto what rpm can this measure ?

Click to expand...

The circuit has a couple of mistakes;
for starters, the comparator IS NOT set up as a Schmitt trigger, as it lacks positive feedback, and thus is sensitive to noise.
Whoever designed this circuit noticed this noise sensitivity, and added a 100n capacitor (which would make the risetime slower) and limit the maximum frequency.

Lastly, it offers the following statement: The last 10K resistor (R7) is an optional pull-up resistor.
No, it is not optional. It is true that R6 and LED2 do pull up the signal, but because of the LED's forward voltage drop, it won't pull it all the way to 5 volt.

Hi

how about the below module?

**broken link removed**

Can I able to achieve 6000rpm ?

Regards,
Vikash

These cheap modules do not provide any meaningful specifications.
I mean, who cares if the module weighs 3 or 4 grams?

But actual design specs, like the maximum count frequency, are sorely lacking. Most likely because the poor performance.

6000RPM equals 200 Hz, with a two slot wheel (bare minimum). It is a relatively slow frequency. It may work.

Eventually, you will have to make a decision, purchase one and test it yourself. There is no other way to answer your question.

Hi,

is there any technical description? If not - how do you think one of us can answer your question?

Klaus

You might be able to use a frequency counter and
a bit of arithmetic, picking off the armature voltage
spikes from commutation via a blocking cap (if the
spikes are large enough for the frequency counter
to "see").

How many spikes per revolution, you'd have to
measure or deduce.

KlausST said:

Hi,

is there any technical description? If not - how do you think one of us can answer your question?

Klaus

Click to expand...

I am trying to implement a test rig to test my pump.

The pump runs with CAN bus where it spits out the speed of the pump.

but externally i need to connect the speed sensor to measure the speed and compare the value with the CAN bus values and prove both are same. There might be a 10% deviation int he speed.

The max speed of the pump is 6000rpm.

The pump voltage is 32V max.

I would like to in interface the sensor output with Labview and see the speed values in the labview software.

https://uk.farnell.com/honeywell/sng-qpmb-000/quadrature-speed-direction-sensor/dp/2773612

The above model looks it will satisfy my requirement and and it had a wide frequency range of 3Hz to 20KHz. 24V max input voltage.

What you are showing is a reluctance sensor.
It only works if you have a toothed wheel with the dimensions shown on table 2.

- - - Updated - - -

I'm going to show you a project which I finished last month, and works very nice.

I have a Wilesco Steam Engine kit with an attached generator (which powers some lights) and a power take off to drive accessories. See the image.

I wanted to read the generator voltage and the the RPM, to add a nice touch. I wanted to keep the vintage look, so the voltmeter is analog.

The voltmeter was simple, just add one in parallel with the generator output.
For the tachometer, I added 10 white stripes to the black flywheel. Close to it I placed a photo-reflective sensor.

The attached schematic are the electronics. Since I wanted to keep the look vintage with an analog meter, I used a frequency to current converter with a LM331. But the part that interests to you is how I clamp the phototransistor's output to one Vbe via the 2N3904.
This is the crucial part....phototransistors have lots of base capacitance which limit the maximum pulse frequency. With this arrangement, I could go as high as 1000 Hz (close to 6000 RPM with 10 slots) with a nice squarewave at the collector.

Just omit the whole LM331 circuit and thake the output from the 2n3904 collector.