Robot Vacuum - DC Motor Problem

Thread Starter

Aleksandr Gonzales

Joined Jan 15, 2016
27
Good day!

I have a Robot Vacuum which does not turn on. So, I opened it up. I removed the vacuum DC motor and left the wheel direction DC motor and the vacuum powers again. Both DC motors are connected in the same pads (M+ / M-). But the weird thing is that, when I removed the DC motor for vacuum, it powers on. But if I connect it again, it does not. So I tried hooking up the DC motor directly to the 3.7V battery and it works fine. The Diode (SS54) (Labeled D1) goes hot when I connect the vacuum DC motor and try to turn the power on.

Here is the PCB:
188048081_483162732992784_4630044433945524655_n.jpg
 

AlbertHall

Joined Jun 4, 2014
11,318
Maybe the vacuum motor, though working, is drawing a lot more current than it should. The problem here is that we have no way of knowing how much current the should draw. Does it have any markings on it that might lead to finding some data on it?
 

Thread Starter

Aleksandr Gonzales

Joined Jan 15, 2016
27
Maybe the vacuum motor, though working, is drawing a lot more current than it should. The problem here is that we have no way of knowing how much current the should draw. Does it have any markings on it that might lead to finding some data on it?
Unfortunately, no marking on the motor sir. Just with 224 electrolytic capacitor with it. I changed C4, C6, and C7 for based on my multimeter, it shows continuity, thus shorted to ground. The C4 is the culprit, but I changed C6 and C7 first. Goodness. Now, it doesn't have a short.

I connected a 1000 mAH 3.7V battery (low amp / computer mouse battery) parallel with the 18650 3.7V battery (just to give some boost). And it works. I don't know why.
 

KeithWalker

Joined Jul 10, 2017
1,790
The motors in those usually have sleeve bearings. If the bearings dry out and become clogged with fine dust particles the motor will draw more current. Try lubricating the bearings, very sparingly with some thin lubricating oil. Take care not to get any on the brushes or commutator.

I was too slow typing. You got it fixed.:)
 

Thread Starter

Aleksandr Gonzales

Joined Jan 15, 2016
27
The motors in those usually have sleeve bearings. If the bearings dry out and become clogged with fine dust particles the motor will draw more current. Try lubricating the bearings, very sparingly with some thin lubricating oil. Take care not to get any on the brushes or commutator.

I was too slow typing. You got it fixed.:)
Thank you sir! Will lubricate it too. And apply grease on gears. Hehe. I think the short drains much battery operation time. Because it is flawlessly working good now.
 
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