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Samsung VAC issue

starLED

Member
I have Samsung Vacuum Cleaner VCDC20AH.
Recently I have replaced original motor with non-OEM motor.
VAC works fine but it turns off by itself after 5 min. of vacuuming.
Can the problem be the thermal fuse?
 

ramondo

Member
I would suspect a thermal cutout in the motor assembly, IF it restarts after cooling down.
 

ramondo

Member
Was the replacement motor designed as a replacement of the original motor?

1. thermal cutout faulty
2.thermal cutout not rated as original
3.insufficient airflow for cooling
4.blocked intake
5.improper reassembly (I have put the impeller on backwards before) air must blow through the motor.

last option (Not recommended) is to locate and bypass thermal fuse,, highly unlikely to have it overheat and not be noticed by operator.
 

starLED

Member
Was the replacement motor designed as a replacement of the original motor?

1. thermal cutout faulty
2.thermal cutout not rated as original
3.insufficient airflow for cooling
4.blocked intake
5.improper reassembly (I have put the impeller on backwards before) air must blow through the motor.

last option (Not recommended) is to locate and bypass thermal fuse,, highly unlikely to have it overheat and not be noticed by operator.
Replacement motor is exactly the same as original motor.
Where is thermal cutout located usually?
 

ramondo

Member
Normally wound into the field windings of motor,sometimes visable on close inspection and sometimes buried under a lot of tape.

see the following


Look for youtube vids on same

also look for "thermal reset in vacuum motor" on youtube
 

starLED

Member
Normally wound into the field windings of motor,sometimes visable on close inspection and sometimes buried under a lot of tape.

see the following


Look for youtube vids on same

also look for "thermal reset in vacuum motor" on youtube
I watched video you posted.
I don't remember seeing anything resembling thermal cutout like in the video when I replaced the motor.
There was some part that is hooked on the side of motor, that I have put from old to new motor, but I don't know what was it, two wires from the motor goes into it.
I will disassemble VAC and post a image of it.
 

starLED

Member
I found picture of motor on web.
Is the thermal cutout this part that black and brown wire goes into?
 

Les Jones

Well-Known Member
Most Helpful Member
Have you checked that there are no filters or dust collection bags that clogged up with dirt which would reduce the air flow. With less air flow the motor will get hotter.

Les.
 

starLED

Member
I want to test motor and thermal cutout.
I have a multimeter that can measure temp.
Motor is Class F, if I am right, max temp of this motor is 155 C degrees.
So, I want to test if motor reaches that temp before it's shut down by thermal cutout.
Any suggestion how to test this?
This is the picture of PCB of VC (sorry, it's a little bit blur).
IMG_20201109.jpg
 

ramondo

Member
After seeing photo on last post I lean to a software or solid state fault. I would suggest measuring the yellow plug for voltage. Voltage may be AC or DC . If voltage is present when vacuum stops the motor or cutout is likely bad. If voltage is not present the PCB or some other connection could be at fault.
A High Res photo of the circuit board would help, a schematic would help, F***ing engineers. Its a Vacuum.
 

starLED

Member
OK, I have disassembled VAC, and tested a bit.
Motor reaches 130-150C before it shuts down after running for about 1-2 min. with full vacuum (I covered motor intake) which is I think too little.
AC voltage is present at yellow (motor) plug at PCB when motor is shut down, it's 33 V.
If I am correct, motor is getting too hot too soon, and considering it's a brand new non-OEM motor, I guess it's a crap motor.
Am I right, or can something else be a problem?

I found on web PCB pictures and schematics, look at https://forum.cxem.net/index.php?/topic/140828-пылесос-samsung-sc4760/

 
Last edited:

ramondo

Member
Motor reaches 130-150C before it shuts down after running for about 1-2 min. with full vacuum (I covered motor intake)


THIS may be normal operation. Motor needs airflow.

? 33v ? I believe that TR1 should be switching line voltage on or off.
What is the input voltage on plug P1 ? I have been assuming 220v or 110v
Is this vacuum speed adjustable by ir remote control?
What is switch SW1 used for?

If you are comfortable working on a live circuit I would suggest using coolant spray on selected PCB components (should delay cutoff or May restart when correct part is chilled); Or using a hot air device on same components when vacuum is cool ( should cause early shutdown). Alternatively putting PCB in freezer to lower it to around 20 deg f then seeing if motor runs longer after reinstalling PCB (verify motor or PCB fault).
 

starLED

Member
Input voltage on P1 is 220V.
On handle there are remote control buttons for vacuum speed (Max, Mid, Min) and On/Off.
SW1 is a switch button on VAC.

PCB in freezer is an interesting idea, I could try that, but I am 99% positive that motor is faulty.
And besides that, why cooling PCB when cutoff is (I think) on the side of the motor (look at picture #8)?
 
Last edited:

ramondo

Member
At this point I would measure ac voltage at plug P2 for max speed when cold start. If 220v I would wire plug P2 to 220v supply verify that the motor runs properly or still cuts out. Problem will be on either motor/cutout or PCB.
 

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