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Not able to recognise this motor type

Les Jones

Well-Known Member
Most Helpful Member
Replace D1 with the same part number. (Or use a device with the same or higher current rating.)

Les.
 
I removed D1 and tested. But only LEDs are working not Fan. Do I need to add New D1 ?

IMG_4328.JPG
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
Assuming it's just a protection diode?, then it does absolutely nothing until you connect the battery the wrong way. Stick a diode in and try it - you could hang a through-hole one across the board for testing (1N4001 etc.)
 

Les Jones

Well-Known Member
Most Helpful Member
I agree with Nigel that it should work without the diode.
Can you elaborate when you say that the LEDs are working. I would expect them to light up in different patterns to indicate some state of operation. For example on/off timing functions, fan speed etc. We don't have a manual for your fan so we can only guess what the LEDs indicate. Does turning the potentiometer do anything ? Is there any voltage (And what is it) between the GND and VDD pins of the fan connector ? You are making it difficult for us to help you by not answering questions and providing VERY limited information.

Les.
 
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tonigau

Member
Just a bit of info on the fan...
I got 3 of these fans (another badge/brand) on big special quite happy with the performance.
1 failed after a few months (LED's ok but no run) & I got a store replacement.
The board & wires are really jam packed in there. Hoping the fans keep working long enough that I can get around to making a PIC PWM controller battery charger.
When I first looked at it I didn't think it was a BLDC motor, couldn't feel any cogging, but realized it is specially designed for fan so the poles will be low cog/noise designed after seeing the 3 motor connections.
The LED's are battery charge indicators, about 20% each LED. When running & low LED flashing motor speed reduces in steps. .
While charging the top LED flashes, this is CC, when all LED's on & no flashing it is CV mode. I usually stop charge once the flashing stops(about 90%) for longer battery life.
The speed pot gives about 20 steps, (so its technically not 'step-less' as advertised)
I did a charge test to gauge how accurate the advertised battery rating is & it looks ok.
On the graph, Blu is Volt, Black is Amp, Orange is calculated Power.(Red is shunt mV)
The plug-pack power supply is a Constant Current type with about 27V open circuit, so don't connect the fan to a 24V power supply to charge unless it has adjustable current regulation.
The fan also is a 'power bank' with USB socket for charging devices.
The plug-pack runs 30deg.C above ambient so I expect early fail.
 

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tonigau

Member
I think the "Capacitor, no details" is actually an inductor, so the circuit T1, L?, D1 C? is a buck converter for battery charging.
Looking at the graph in previous post we can see the current is controlled.
Replace the same SS34 schottky diode, check replace the MOSFET & capacitors.
It looks like the + solder join of battery connector is cracked.

Toni

1651964345227.png
 

Les Jones

Well-Known Member
Most Helpful Member
I agree with Toni that the item that marked as "capacitor no details" is an inductor. (It looks like an inductor AND is marked L1 on the PCB.) I did not bother mentioning this as I assumed it was just for power supply filtering but I think Toni is correct that it is part of a switching regulator. (And I was wrong about D1 being for reverse polarity protection.) When you eventually get round to answering the question about the semiconductor part numbers (Particularly T1 and T2 so that we know if these are P channel or N channel devices.) we will get a better idea of how the circuit works.

Les.
 
I agree with Nigel that it should work without the diode.
Can you elaborate when you say that the LEDs are working. I would expect them to light up in different patterns to indicate some state of operation. For example on/off timing functions, fan speed etc. We don't have a manual for your fan so we can only guess what the LEDs indicate. Does turning the potentiometer do anything ? Is there any voltage (And what is it) between the GND and VDD pins of the fan connector ? You are making it difficult for us to help you by not answering questions and providing VERY limited information.

Les.
LEDs are battery indicators to show 1st LED =10%, 2nd LED 20% and so on. The Potentiometer is for turning on and off as well as speed control. GND and VDD pins have 25.9V DC. I'm trying my best to Answer all the questions from end and you guys Helped me a lot. I don’t have any knowledge about electronics, so this might be a problem to understanding your questions. But I'm trying hard and do research to understand everything :)

And I'm sure with help of you this fan will start working again ;)
Thank you so much for your Time and Effort.
 
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Just a bit of info on the fan...
I got 3 of these fans (another badge/brand) on big special quite happy with the performance.
1 failed after a few months (LED's ok but no run) & I got a store replacement.
The board & wires are really jam packed in there. Hoping the fans keep working long enough that I can get around to making a PIC PWM controller battery charger.
When I first looked at it I didn't think it was a BLDC motor, couldn't feel any cogging, but realized it is specially designed for fan so the poles will be low cog/noise designed after seeing the 3 motor connections.
The LED's are battery charge indicators, about 20% each LED. When running & low LED flashing motor speed reduces in steps. .
While charging the top LED flashes, this is CC, when all LED's on & no flashing it is CV mode. I usually stop charge once the flashing stops(about 90%) for longer battery life.
The speed pot gives about 20 steps, (so its technically not 'step-less' as advertised)
I did a charge test to gauge how accurate the advertised battery rating is & it looks ok.
On the graph, Blu is Volt, Black is Amp, Orange is calculated Power.(Red is shunt mV)
The plug-pack power supply is a Constant Current type with about 27V open circuit, so don't connect the fan to a 24V power supply to charge unless it has adjustable current regulation.
The fan also is a 'power bank' with USB socket for charging devices.
The plug-pack runs 30deg.C above ambient so I expect early fail.
Thank you for making it simple to understand :)
 

tonigau

Member
They would be P-ch HI side switches as the gate is switched between +V & -V by gate drive T4 & T5 <-- PWM from uC.
There is a blocking diode D2 that prevents +Vbat backfeed to DC in connector.
I found a photo from last year of mine, can see the MOSFET numbers (BA6H13) but I cant find any data.

Schottky diode D1 would likely have cracked due to excess reverse current if its breakdown was compromised, possibly due to intermittent battery connection? or maybe just a bad part.
Testing... (bare board, connectors removed)
If you set your meter to Diode test, check D2 for about 0.5V one way & much higher the other.
Do the same with the 2 MOSFET's T1 & T2 Drain & Source (pins soldered together in my picture). They should test similar to the diode. If it shows about 0.1V then likely dead diode/MOSFET.
If T1 or T2 dead then will need to check driver transistor pairs T4 T5 & T3 T6. These are likely small signal BJT.

If D1 is removed & is the only component fault, fix solder join to battery & battery has charge the fan should run, this is a good test.
Looking at the PCB copper, Battery V+ comes via L1 -> T1 -> T2 to Fan VDD pin.

You will need to learn de-soldering/solder techniques, leadfree solder is harder to melt than good ole 60/40. I find diluting the leadfree with leaded solder helps.


1652071634292.png
 
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They would be P-ch HI side switches as the gate is switched between +V & -V by gate drive T4 & T5 <-- PWM from uC.
There is a blocking diode D2 that prevents +Vbat backfeed to DC in connector.
I found a photo from last year of mine, can see the MOSFET numbers (BA6H13) but I cant find any data.

Schottky diode D1 would likely have cracked due to excess reverse current if its breakdown was compromised, possibly due to intermittent battery connection? or maybe just a bad part.
Testing... (bare board, connectors removed)
If you set your meter to Diode test, check D2 for about 0.5V one way & much higher the other.
Do the same with the 2 MOSFET's T1 & T2 Drain & Source (pins soldered together in my picture). They should test similar to the diode. If it shows about 0.1V then likely dead diode/MOSFET.
If T1 or T2 dead then will need to check driver transistor pairs T4 T5 & T3 T6. These are likely small signal BJT.

If D1 is removed & is the only component fault, fix solder join to battery & battery has charge the fan should run, this is a good test.
Looking at the PCB copper, Battery V+ comes via L1 -> T1 -> T2 to Fan VDD pin.

You will need to learn de-soldering/solder techniques, leadfree solder is harder to melt than good ole 60/40. I find diluting the leadfree with leaded solder helps.


View attachment 137007
Can I get any ready-made new circuit like this or similar to this to start FAN? anything will do. I just wanna start fan. I'm ok with no speed control and without battery
 
Last edited:

Les Jones

Well-Known Member
Most Helpful Member
Hi Tony, I have found a datasheet for the 4407A mosfet.
http://aosmd.com/pdfs/datasheet/AO4407A.pdf
With the limited part of the schematic I have traced out I cant understand why the drain of the P channel mosfet is connected to positive.
I have just noticed that the TS has just posted again. It sounds like he is not prepared to put any effort into repairing the original board. He just seems to want a replacement board. I think the chance of getting one is close to zero.

Les.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
The fan motor itself appears to use a very common connection type, using the same style of control as many PC and small industrial fans.

If the motor is still working, it should run simply with positive and negative power connected, then the PWM input either left open - try that to start with - or connected to a 5V source (relative to the motor 0V/ground).

Note that anything more than about 5.5V on the PWM pin will probably wreck the motor.

Connecting the PWM input to 0V should stop the motor.

The motor control electronics are built in to the fan motor casing, the only external electronics required are for speed control if you want that instead of on/off.

For speed control, you probably need a PWM frequency around 25KHz and the speed should then be proportional to duty cycle, 0-100%
 

tonigau

Member
With the limited part of the schematic I have traced out I cant understand why the drain of the P channel mosfet is connected to positive.
The Drain of T1 is to battery positive, is this what u mean?
Source (3 pins) of T1 & T2 are connected to +DC in via Diode D2.
.
This is how I see it working...
T1 is PWM'd via buck circuit to the battery & T2 would be just switch on while PWM goes to the integrated BLDC controller inside the motor.
To run off battery T1 & T2 are switched on (T1 body diode conducts initially.)

If the DC in is on & the fan is switched on, i assume the MCU via R7 22k senses Vin & stops T1 PWM (buck), maybe motor load is enough to control charge current if T1 on.
 
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tonigau

Member
If I get time I will check the motor PWM characteristics.
I have been trying(not too hard) to find a supply of these motors to make some ceiling fans as I won't have mains power in the new house build. They run very quiet, unlike many single phase BLDC fans.
 
Hi Tony, I have found a datasheet for the 4407A mosfet.
http://aosmd.com/pdfs/datasheet/AO4407A.pdf
With the limited part of the schematic I have traced out I cant understand why the drain of the P channel mosfet is connected to positive.
I have just noticed that the TS has just posted again. It sounds like he is not prepared to put any effort into repairing the original board. He just seems to want a replacement board. I think the chance of getting one is close to zero.

Les.
If chances are close to zero, then I will have to put effort into preparing original board :)
 
The fan motor itself appears to use a very common connection type, using the same style of control as many PC and small industrial fans.

If the motor is still working, it should run simply with positive and negative power connected, then the PWM input either left open - try that to start with - or connected to a 5V source (relative to the motor 0V/ground).

Note that anything more than about 5.5V on the PWM pin will probably wreck the motor.

Connecting the PWM input to 0V should stop the motor.

The motor control electronics are built in to the fan motor casing, the only external electronics required are for speed control if you want that instead of on/off.

For speed control, you probably need a PWM frequency around 25KHz and the speed should then be proportional to duty cycle, 0-100%
Motor is not working using 5v DV power.
 

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