Monitor speed of TWG3246-TEC2430 DC motor.

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Monitor speed of TWG3246-TEC2430 DC motor.

Does anyone have experience in monitoring the motor speed of a DC brushless motor via the FG (Frequency Output - 6 pulses per revolution).

I understand it emits 6 high pulses per revolution and the motor runs at 4500RPM.

I am thinking an array to capture the number of pulses per second, then if the number reduces below a threshold I can turn the motor off. Basically an overload cut out.

Haven’t started any coding as yet.

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Do you have any specifications for the FG output?

I have used this circuit to monitor the pulses from a DC motor that has a feedback coil.

tachometer_schematic
tachometer_schematic901×401 2.56 KB

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image
image1065×472 154 KB

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Hi Jeff, need to use an Arduino Nano for the job

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That’s not a simple feedback coil sensor. The reference to CW and CCW suggests it has some form of controller built in. The pulse output is labelled OC so all you would need to do is to pull it up to 5V (@3ma) and feed it direct to the Nano interrupt input. I would also guess 9 ppr, not 6. Google translate will be a big help.

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Thanks Jeff.
I’ve managed to use the CW and CCW wires to run in fwd and rev by grounding them.
You are right there is a controller in the motor and the specs on that sheet say 9.
I will have a go at what you recommend and get back to you next week.
Thanks again for your patience, I have to start learning and this is it.

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Hi @James281657, Welcome to the forums!!!

DC Brushless suggests @Jeff105671 is right and that it does have an onboard Electronic Speed Controller (ESC)

If you have a link to the Datasheet documents that would be helpful.
I haven’t been able to find some similar to the image you posted but I’d be keen to have a look at it.

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Hi Aaron,
I really appreciate any help I can get before I start trying to code my Arduino.
This is the link to TT Motors who make them.
If you don’t trust links, just search TT Motors and look for the model number above.

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Hey @James281657,

Links are totally fine, but we’re struggling to find the location of the table you sent previously. The website has a 1-page datasheet with some basic motor input. I expect we’re just missing something, but if you could provide a source for that table that’d be awesome.

Thanks!

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TT Motors emailed me that one page.
That and the following detail is all I have.
I think Core sell these motors as well.
Features:
1.Small size dc gear motor with low speed and big torque
2.32*46mm gear motor provide 1.0Nm torque and more reliable
3.Suitable to small diameter, low noise and big torque application
4.Dc Gear motors can match encoder,12ppr-1000ppr
5.Reduction Ratio: 70、146 、188、300、438、463、700、900、1020、1313、1688、2700;

Application:
BOAT, Industrial equipment.

Electrical Specification
Part Number: TWG4058-555PM
Power:2.2-6.7W
Rated Voltage:12 -24V
Continuous Current(A):500-800mA
Rated Torque:8kg. cm
Rated Speed:4500RPM
Type:DC Worm Gear Motor
Efficiency: 80%-90%
Construction:Permanent Magnet
Direction of Rotation:CW/CCW
Noise:30cm.<40db
Average Backlash no load:<3°

Physical Specification:
Motor Size:24.430.8mm
Motor Diameter:24mm
Gearbox Size: 3246mm
Shaft Length: 15mm
D-cut Length: 12mm
Shaft diameter:6mm
Weight:150g

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Do you have some pictures of the motor that you can take yourself? It looks like it has 4 wires out but I can’t be sure from the pictures on their page. Unfortunately, we still don’t know a great deal about these but we can still begin to start exploring some other options

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Thanks Jack,
5 wires.
Red is permanently attached to positive.
Black is permanently attached to earth.
To make the motor run.
Attach white to earth (low) and the motor starts. (high makes it stop)
Attach white and orange to earth for reverse.
The yellow wire sends the pulses as an output.

5 WIRE MOTOR
5 WIRE MOTOR1920×1440 167 KB

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Before connecting it to an Arduino Nano can you test that the max output from the pins is 5V? If so this could be as simple as time what it takes to hit 6 pulses.

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I will get back to you on that

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The yellow wire is marked as Open Collector (NPN), so you can’t just measure the voltage. You could try measuring the resistance to ground, but the better option would be to provide a pullup to 5V via a 20K resistor. That guarantees that the voltage is suitable for a 5V MCU (which is the point of making it OC).

The reference to a phase shift suggests that the pulse rate might be the PWM rate and the phase shift indicates the rotation speed.

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