Replacing a small DC motor from a paper collator

[ryancparadiso]

Hi all

I am looking to source a specific mini DC motor for a paper collator tower. I have removed the motor, and attached pictures of it. The motor runs intermittently when in test mode, but sometimes sputters (turns a little, stops, tries to turn a little...), which trips the error system. When testing its wires for continuity, I consistently get a reading of 10-15, so it seems like there is some resistance. And, when I turn the spindle manually, it seems to get 'stuck' / find patches of physical resistance, though I'm not familiar with motors and so am not sure if this is normal or not.

All of the information I have about it, which is also on the picture, is:

DC Motor
Type SP
No. FM-36E
China | Fuji Micro
(and on the other side, a sort of serial(?) number: ID24 JSP)

measurements:
- body: 1.5 in diameter, 2 in. length
- spindle: 5/32 in. diameter, 1 in length

The company no longer supports this machine, and does not have any replacement motors. I have not been able to locate it online, and don't know enough about it to know what sort of new motor might work. Any help would be appreciated! Thank you so much~~

 

[Tony Stewart]

You will need to specify Voltage, RPM, and mechanical interface dimensions.

e,g,

https://catalogue.precisionmicrodrives.com/product/datasheet/110-001-10mm-dc-motor-13mm-type-datasheet.pdf

 

[ryancparadiso]

Tony Stewart that makes sense, and I wish I knew those things! All I have is the maintenance manual for the entire machine, which only tells me that it is 24V and 0.46 A. Do you know how I might test for RPM, etc?

 

[Tony Stewart]

Tony Stewart Do you know how I might test for RPM, etc?

Is it high RPM like 20kRPM ? A mic recording and Audacity FFT can tell you RPM. There are are still a bunch of suppliers of micro DC brush motors such as Panasonic where you need to match mechanical and voltage.

 

[ryancparadiso]

Tony Stewart that's a fun idea! I'll record it and see if I can't pick the RPMs apart via audacity. It's not super fast, though my lack of knowledge in this area might not help even locate a guess at the RPMs—it controls rollers for feeding paper through binding equipment.

 

[Tony Stewart]

So then you would expect lots of harmonics from gear noise and may need to measure time interval per rotation.

 

[ryancparadiso]

Tony Stewart I reattached the motor to the machine, and ran it in test mode to isolate the motor. I put a small piece of tape around the shaft so that it would make a noise with each revolution, then imported to audacity, zoomed in, found the time per single rotation (.013-.014 s), then used that to get 4285-4615 rpm.

I tried this while hooked up to the gears in the machine (though still isolated this motor in test mode), but yes, too much extra noise to clearly define a single revolution

 

[rjenkinsgb]

It looks like a "775" style, 24V 5500 RPM long shaft.

Example for dimensions - I don't have time to search for all the right details at the moment, I have to go to a customers site.

High Speed Motor Gear 775 DC12V/24V 4500/5500/12000RPM Large Torque Ball Bearing | eBay

No-load speed: 12000 rpm, 4500RPM rpm, 5500RPM rpm. -High torque and low noise. Mounting hole pitch: about 29mm. Motor step height: 4.5mm. The step height of the motor tail: about 7mm. The length of the shaft: 16mm (the length of the shaft above the level of the step).

www.ebay.co.uk

And a long shaft example, but wrong speed..

https://www.amazon.co.uk/Motor-Extension-Torque-Office-Automation/dp/B0CBVL7X5B?th=1

 

[Les Jones]

I suggest measuing the voltage at the motor terminals when the motor is running. As you say the machine requires a 24 volt power supply the motor is probably 24 volts but is may be a different voltage so it is worth confirming this before ordering a motor. You can find optical tachometers on ebay for about £11.00. I don't know what a paper collator tower (And you have not told us the model number for us to Google it.) is but I am guessing it feeds sheets of paper. If you work out the gear ratio between the motor and the paper feed you may be able to time the rate of paper feed and thus calculate the motor speed.
Les.

 

[Tony Stewart]

Hi all

I am looking to source a specific mini DC motor for a paper collator tower. I have removed the motor, and attached pictures of it. The motor runs intermittently when in test mode, but sometimes sputters (turns a little, stops, tries to turn a little...), which trips the error system. When testing its wires for continuity, I consistently get a reading of 10-15, so it seems like there is some resistance. And, when I turn the spindle manually, it seems to get 'stuck' / find patches of physical resistance, though I'm not familiar with motors and so am not sure if this is normal or not.

All of the information I have about it, which is also on the picture, is:

DC Motor
Type SP
No. FM-36E
China | Fuji Micro
(and on the other side, a sort of serial(?) number: ID24 JSP)

measurements:
- body: 1.5 in diameter, 2 in. length
- spindle: 5/32 in. diameter, 1 in length

The company no longer supports this machine, and does not have any replacement motors. I have not been able to locate it online, and don't know enough about it to know what sort of new motor might work. Any help would be appreciated! Thank you so much~~

You'll need to use metric measurements to match motors and specify the shaft diameter.
5 mm ? 8, 10 ?

 

[ryancparadiso]

Hi all, just want to revive this thread with some updates.

So, I sourced a few motors, none of which were perfect, but good enough to at least test with. I also cleaned and reassembled the original motor.

I tested the original and new motors via the machine's motor maintenance mode, and all of the motors reacted in the same way: they will run at full speed for 1-2 seconds, then drop down to a fraction of the speed for 1-2 seconds, then cut completely. And after that, I can't get them to start up again.

Does anyone have a theory as to what might cause this sort of motor behavior?

It seems that something upstream of the motor is the issue. The maintenance manual says, at this point, to check the conductance of the wires, and then replace the entire circuit board (which would cost more than I paid for the entire machine in the first place...). I've removed the circuit board and am going to go over it with a magnifying glass to check for any cracked solders etc, and then maybe go through the entire machine and clean every single wire connector I can find and re-seat them. Any other ideas?

Thank you all so much, you've been a huge help~~

 

[Les Jones]

If the motor is connected but NOT driving the cutting blades does it still behave in the same way. I am thinking that there may be something tight in the cutting blade part which is making the motor draw more current than normal and the electronics is cutting off the supply to the motor to protect it. Can you trace out the schematic of the control board so we can see if there is any overcurrent protection circuit.

Les.

 

[ryancparadiso]

If the motor is connected but NOT driving the cutting blades does it still behave in the same way. I am thinking that there may be something tight in the cutting blade part which is making the motor draw more current than normal and the electronics is cutting off the supply to the motor to protect it. Can you trace out the schematic of the control board so we can see if there is any overcurrent protection circuit.

Les.

I should have clarified, these tests were done with the motor not attached to any drive system—so, just the wires into the motor, with a bare spindle. I should note, this is also what was happening as the unit began to fail, while properly connected to the drive belts etc. I've attached some relevant pages from the manual here re: wiring path (See pg. A-21-A-25, specifically 25 and 23, where I've marked the path of the motor wiring), but there isn't a detailed schematic of the circuit board itself. I can take a high res photo of the circuit board, if that'd be helpful.

 

[rjenkinsgb]

hey will run at full speed for 1-2 seconds, then drop down to a fraction of the speed for 1-2 seconds, then cut completely. And after that, I can't get them to start up again.

Could it be a fault in some form of load sensing circuit? eg. it is acting as if it's emptied its source bin?

Is it a stand-alone unit or does it connect to a printer / copier?

If it interfaces to another unit, does it have an electrical connection to that, or only some form of input sensing??

 

[ryancparadiso]

Could it be a fault in some form of load sensing circuit? eg. it is acting as if it's emptied its source bin?

Is it a stand-alone unit or does it connect to a printer / copier?

If it interfaces to another unit, does it have an electrical connection to that, or only some form of input sensing??

Ah, I see what you mean— this behavior is happening in the machine's test mode, in which pressing the start button should make the motor run as long as the button is pressed.

It does connect to a downstream unit, but this behavior happened when set up by itself.