# DC12V 12A car window motor - what spec for a 220V PSU?

The current measurement obtained on the 8A charger range with 1 kg load appears to be a mis-read (shown in red).
View attachment 207046
Thank you very much for checking my figures.
My guess is that I have inadvertently swapped the figures between the 2kg and 1Kg loads.
If this is so, the table should read:

4A delivers 12V free of load
8A delivers 13.55V free of load

4A delivers 10.3V motor load - no weight - 88 rpm - 1.5 A
8A delivers 12V motor load - no weight - 104 rpm - 1.6 A

4A delivers 9V motor load - 1 kg - 60 rpm - 2.1 A
8A delivers 10.9V motor load - 1 kg - 80 rpm - 2.4 A *

4A delivers 8.7V motor load - 2 kg - 54 rpm - 2.3 A
8A delivers 10.3V motor load - 2 kg - 68 rpm - 2.8 A *

* bold results swapped.

I'll run the tests again, after cleaning up the gearbox.
My next post will show the gearbox dismantled.

Motor Gearbox Examination
Lots of interesting discoveries made here.
I made a video, as it's easier to discuss each issue:

So the motor units were swapped.
This time, the shaft seal was included in the assembly.

Note the spring
The seal is from a water pump, has two seal faces, and apparently compresses the shaft seal, as the spring is compressed.

The result is that the motor rpm has substantially slowed.

Clockwise = 34 rpm
anticlockwise = 68 rpm​

Is this just coincidence?

Very nice though, because by good fortune... so far, I have a two speed motor, and both speeds are where I want them to be.
Ahhhh!
Let's allow ourselves a brief glimpse of superstition, and suggest that this is karma

Last edited:
Testing The Motor @ Supply 13.5v No load (stated 8 Amps)

These tests seem to be inconsistent.
This may be due to my gauging of the median between high and low.
Also, the motor is getting hot.
But even RPM results jump a bit.

Perhaps the unit is bedding in... as also the seals.

Anyway... having done the testing, I include the results below.
We at least have the ballpark figures.
It may be better if I re-test the unit after giving it some work.
---------------------------------------------------

Clockwise = 34 rpm - 8.36 V - 3.95 A
anticlockwise = 68 rpm - 9.85 V - 2.84 A

Engine Barrel 1.7 Kg
Clockwise = 30 rpm - 8.25 V - 3.90 A
anticlockwise = 56 rpm - 9.45 V - 3 A

Weight 1 Kg
Clockwise = 32 rpm - 8.30 V - 3.95 A
anticlockwise = 64 rpm - 9.70 V - 2.98 A

Weight 2 Kg
Clockwise = 35 rpm - 8.38 V - 4 A
anticlockwise = 66 rpm - 9.58 V - 3.20 A

The development project has gone very well.
I removed a seal that I believed to be too tight... but the motor still remains protected by two seals.

After putting the turntable to work... it is clear that the motor is not under excess load... it sounds fine.

The 1.5 sq mm cable runs for approximately 10m.
This conveniently allowed my battery charger to remain in it's original position.

I didn't have a 'latching' reversible polarity switch - the window winder switch is 'hold to make contact', therefore:
The control panel was created using 3 x '3 pole' (light) switches, mounted on two 'cork backed dinner placement mats' (to provide screw depth).

2 switches were mounted side by side, with the inner and outer poles connected.
The third switch breaks the live feed.

The 2 switches controlling polarity reversal, require bridging (a bar, top and bottom, across the the switch interface).

The advantage of the large switch interface, is that they can be 'foot operable'.
It doesn't get better than that, as both hands are ensconced within 'operator gloves'.
The left foot controls the turntable... the right foot controls the ejection of the 'material surface modification media'

Results

Engine Barrel 1.7 Kg
Clockwise = 35 rpm - 6 V
Anticlockwise = 68 rpm - 7.80 V

These speeds tested well for the removal of the first few surface molecules (using very sharp micro particles).
I have yet to attempt any densification.
However, successfully completing the first phase, leaves me confident of final surface modification.

Adding a fuse into the circuit.
The original fuse, provided with the motor is a straight 15 Amps (30mm x 6.3mm).

The presumption is that the original electrical engineers got it right.
... but such presumptions are always open to peer review.

From a theoretical perspective... is there an ideal position for the fuse?
Placing it close to the PSU seems logical, though that is 10m away from the motor.

Joining The switches
The switch actuator is rigid enough, but thin.
Rather than hot gluing two bars... I will add material on the underside of each actuator.
In this way, I can screw the bars in place.

This will enable easy dismantling, at some future moment.

So far so good... zero time wasted in sourcing components

In the video the gearmotor is noisier In one direction than the other. If you have it apart again, disengage the worm from the gear, and see if noise comes from the motor itself, or if it is (my guess) due to gearing.

Can't tell for sure if it is a fast or slow blow fuse (looks like a fast blow) but a 15A rated fuse at 12V will allow 180 watts of motor power for a considerable time.
During testing you had observed the motor beginning to run hot somewhere in the 35 watt ballpark, so 15A provides only wire protection, and not for motor overload. I'd try a 5A fuse. Installed at the power supply it will protect against a wiring short circuit as well as motor failure/overload.

Looking good!

marcophys
jim hardy
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During testing you had observed the motor beginning to run hot
window motors aren't expected to see continuous duty....

Asymptotic
I will check the motor without worm drive.

I was wondering what is making it a two speed motor, depending on polarity.
I attempted to remove the motor outer casing from the spare motor, but even after heating the screws they weren't budging.
I'll come back to that operation.

Re the fuse
I found a BS1362 5A fuse.
I then opened the charger.
It's a West German Absaar Type 108 NE/D2 with a push button fuse.
However, the fuse has no data on it whatsoever, but T 25 F appears on the underside data sheet.

The Fuse is top left
Wired from the Ammeter to Output.

The fuse button is out and is on a spring.
I presume it must trip on heat.

Any thoughts?
Should I still install the BS1362 5A fuse?

Re motor duty
This is to be seen.
The motor isn't running continuously.
By necessity it is fully enclosed in plastic (as per the earlier photo).
It's a roomy enclosure, but heat will dissipate slowly through the plastic.

I could have it wired to the standard foot switch - but It would mean more stopping and starting.

In Use
It seems to be running freely without signs of protest.
I'm going to complete all the planned operations, and then run some more tests.

jim hardy
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I was wondering what is making it a two speed motor, depending on polarity.
That's interesting, and when you think about it they might have done it on purpose.
One way it's lifting the window which is a several pound load plus friction.
Other way it's lowering the window so runs unloaded.

To get same up and down speeds for aesthetics one would do something to slow unloaded "Down" speed to match loaded "Up" speed.
I've no idea what they did.
Perhaps some clever mechanical trick with friction in the worm drive; ME's are brilliant at such things
perhaps a third brush; a mundane EE trick
perhaps a few turns around the permanent field magnets to slightly aid or oppose them ?

Now you've got me curious - next one i find i'll take apart...

I think that it must be electrical... it is almost perfectly twice or half speed.
Minor difference will probably come from increased friction one way:

Engine Barrel 1.7 Kg
Clockwise = 35 rpm - 6 V
Anticlockwise = 68 rpm - 7.80 V

This voltage was measured only a few inches from the motor at the end of approximately 10m of 1.5 sq mm cable

I've had another look at the screws holding the motor casing.
The problem is that I can't get a T bar in play due to the screw proximity to the casing.
That leaves the screw driver.
Also the screw heads are not hard.

Having already tried with heat, I can see that this would come down to 'drilling out'.
With so much to do, the motor must remain a mystery for the time being.

Re the fuse
I found a BS1362 5A fuse.
I then opened the charger.
It's a West German Absaar Type 108 NE/D2 with a push button fuse.
However, the fuse has no data on it whatsoever, but T 25 F appears on the underside data sheet.
Absaar may be calling the red buttoned device a fuse, but it actually is a push-to-reset circuit breaker wired in series with the charger DC output. Can't say what the "T 25 F" marking means. 25A seems a high current rating for this purpose; Absaar type 108 charging output is 11 amps, and a 15A breaker sounds about right. If the charger is operational with the button out then either it comes out farther when in the tripped state, or it is tripped, but the breaker contacts are welded together.

I presume it must trip on heat.
Many circuit breakers are thermal-magnetic in nature. Long-duration, marginal overloads cause trips due to thermal effects while magnetic principles are used to quickly clear severe overloads and short circuits.

Should I still install the BS1362 5A fuse?
Is the BS1362, 5A fuse in the line cord plug? Or are you asking whether one of these are appropriately rated to provide motor protection?

marcophys
RE T 25 F
I found this catalogue:

On page 4 it shows all the breakers with very similar red buttons.
On page 6 & 7 there are the specs showing temperature rating at 25 deg C

Perhaps therefore: T (temp) 25 F (fuse)

Re potentially welded together
I note that the Klixon buttons are a similar distance out.
This isn't hard data, but....

Certainly my fuse button seems to be out a good distance (6mm).

I have spoken to Absaar, but the charger is pre the experience of the technician.
So I've sent him an email with the photos etc.

BS1362, 5A fuse in the line cord plug?
Yes it fits in the sprung in-line fuse holder.
It's a touch shorter than the original, but the spring handles it.

jim hardy
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BS1362, 5A fuse in the line cord plug?
Yes it fits in the sprung in-line fuse holder.
It's a touch shorter than the original, but the spring handles it.
hmmm

The original fuse, provided with the motor is a straight 15 Amps (30mm x 6.3mm).
Automotive fuses will be rated just 32 volts
Check , it should be written on one end.
Don't rely on an automotive fuse to interrupt line voltage for it might or might not do it. Get a proper 250 volt rated fuse. Any good hardware store should have them , or look in junk electronics (dead PC power supply?) .

hmmm

Automotive fuses will be rated just 32 volts
Check , it should be written on one end.
Don't rely on an automotive fuse to interrupt line voltage for it might or might not do it. Get a proper 250 volt rated fuse. Any good hardware store should have them , or look in junk electronics (dead PC power supply?) .
It is suggested that the auto fuse be replaced by the BS1362, 5A fuse in the line cord plug.
The spring tension is fine.

The original auto fuse was rated at 15A.

jim hardy
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It is suggested that the auto fuse be replaced by the BS1362, 5A fuse in the line cord plug.

Ahhh, thanks for clarification.

I see BSC1362 (a new term to me) is a British standard for line fuses !
http://www.cooperindustries.com/con...oduct-datasheets-a/Bus_Ele_DS_2042_TDC180.pdf

Wikipedia:
https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets:_British_and_related_types
BS 1363, 13 A plugs socket-outlets adaptors and connection units is a British Standard which specifies the most common type of single-phase AC power plugs and sockets that are used in the United Kingdom.
Learn something every day.... Thanks !

old jim

Ha!
Nice data sheet find... good share.

When I searched, the BS site wanted £65 to view the data sheet.
So annoying, particularly as it's a common or garden 'gold standard' that was created in 1947, and modded to include the 5A into the standard in 1973.

As an aside... I see that you've successfully avoided the global debate about BS1363, as to whether this is the ultimate 'plug & socket' connector system (it's best avoided)..

I note that 'fuse users' (everybody) are now advised to weigh the fuses before use to confirm authenticity.
Anything less than 2.2g should be discarded.
Mine is 2.4g
http://www.bs1363.org.uk/DTI_warning_on_Counterfeit_Fuses_web.pdf

Here's a link to a counterfeit BS1362 fuse test page, with a nice video at the bottom, showing a fake fuse exploding on short circuit.
http://www.pat-testing-training.net/articles/fake-fuses.php

Or if you really want to go anal, and see how prime time TV educates the public on fuses... here is the first 10 minutes of a program devoted purely to the the subject of fuses.

I love it!.... it's all down to the sand.
Hence why I proclaimed that I'd found a BS1362 5A fuse.
I thought oooh... that's a good one

jim hardy
jim hardy
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I love it!.... it's all down to the sand.
I'm a believer in sand . It's the arc-quenching medium in fast acting semiconductor fuses like Shawmut 101's.
I've dissected many a fuse for post-mortem forensics on electrical failures ....

Counterfeit fuses ? OMG thanks for the head-up.

Counterfeit fuses ? OMG thanks for the head-up.
I know... it's horrifying.
... and you can no longer rely on print quality as the flag.

Previously everything about them (counterfeits) were crap.
... but now they have the printing to perfection, and they are flooding the market.

It's not the cost of the sand... it's the fact that this entire element of the production line isn't included.
Take away 'sand management & implementation' and everything becomes as easy as a wire , two caps, and a printed enclosure.
... and within that remaining structure... anything goes.

... and apart from electrical failure scenarios...it impacts on quality producers and jobs....
So it's good that TV producers are kicking out these warnings at prime viewing hours.

........ Anyway... I've completed surface densification today.

jim hardy
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... and apart from electrical failure scenarios..
Heaven forbid one of those fuses winds up in somebody's multimeter.

This is video of the explosion that might result (don't worry it's a demonstration filmed with a dummy)
whiteout from fireball lasts 'til 22 seconds

Densification left a polished finish.
Static densification doesn't.

1st phase surface removal media is extremely sharp.
Therefore, on impact a cut occurs, even when the iron surface is passing at the speeds discussed.
Round ceramic dust media must be delivering a glancing blow.
In fact, this is as predicted, though I didn't consider that a polished surface would be the result.

I can get the speed down to 29 rpm @ 5.3V 4.7A (using the slow charge switch on the charger).
35 rpm @ 6V 5.1A (using fast charge switch)

(It looks like that 5A fuse is too light)

If I drop the voltage again, by say by increasing the supply cable length, the Amps will increase again.
Is this problematic to the motor?

26 RPM 4.4V 4.5A

So the volts dropped and the amps dropped.
I expected the amps to rise.

I have to presume that the extension crocodile leads shouldn't be used.
This last measurement was taken with the meter probes screwed into connector blocks.

What I'll do is add another 8m of cable - it's a 4 wire cable - I can simply solder the ends).
I'll measure again using the same system.
This way we should get a genuine difference between the two.

A further 8m cable... so approximately 26m in total.

21 rpm 3.8V 4.35A.

The motor seems to be rotating fine.
The volts are up and down... so the reading is best median.

I've started, so I'll continue.
The goal is to get it to 10 RPM.

This is better.
We have 45m of 1.5 sq mm cable.

With the barrel mounted on the turntable:
11.5 RPM 2.8 V 4 A​

The motor seems to turn okayish... but there is a tight spot, so it slows and speeds up within one revolution.
... but this is to be expected.

The only question is whether the motor can function at this setting, on an ongoing basis.
I will remove the enclosure cover, and simply touch the motor to judge whether it is getting hot.

Ha ha!
The big news that we've been waiting for....

I ran the motor continuously for 10 minutes, and was able to hold my hand on the motor.
It was getting hotter constantly, but thinking of shower temperatures, my guess is that after 10 minutes it reached around 45 - 50 deg C.
To 5 minutes it had barely warmed.

I don't know what the fail point will be, nor the cool down period, but it definitely seems workable.
When I think of typical motors that run for say an hour... you can't even touch them because they are so hot.

Does anybody have any thoughts on this area?

I need to test densification at the new speed, but knowing the speed that one's hand moves over clean iron, I am very confident of success.
11.5 RPM is a crawling pace.
I'll confirm this.

Other exciting news
The enclosure contained ceramic media (what????)

I once saw a doc on the development of a new torpedo.
The camera crew were there for the first trial in the test pool.
It sank!
(I scoffed)
The journalist, in horror, said "but it sank".
The prototype engineer was totally unphased... he said "they all do, the first time".

I take back my scoffing.

The enclosure was unpacked from its polythene wrap - a new stock item.

Yet only one place - and with no outlet... why would the ceramic media be looking to ingress?
The answer is of course positive air pressure.

While the filter is the cost of a small bungalow... it struggles to cope at the 'micro particle level'... so extraction is advised to be restricted
... otherwise the media (the cost of the car in the garage) will be extracted through the filter... and we don't want that.
Hence, there is a slight positive pressure build up, sufficient to find any failings in the enclosure system.

Thankfully, due to the weight of the dust, and the lack of air movement in the enclosure... it looks like the particles have entered the enclosure and for the most part dropped (there was no dusting on the motor itself).
However, this is a cautionary tale for electrical engineers.

The moral of the story is to check the gasket, even when dealing with a new enclosure.
Just the daily differing air pressures might cause an enclosure to breathe.
Then imagine the motor getting warm, heating and expanding the air... forcing some out through the shaft seal?

I'm not sure... the seals are tight.
... but it does raise the question of 'to breathe or not to breathe'?

The ideal must be a diaphragm - say between the lid and box.
Then you could have a hole in the lid (facing down).

The air pressure would be equalised by the diaphragm, ensuring that there would be no external or internal pressure on the shaft seals.

Eliminating the cable

Prior to moving to a PWM system... can the cable be simply replaced with a resistance?
If so... what sort of values should be in the ballpark?

Note: just seen a typo in the previous post.... it should read 35m of 1.5 sq mm cable.

Found a dimmer switch rated 250V AC 40 - 250W
Can this be used?

Diaphragm made, exactly as first suggested.

I put a 3.5mm breather in the furthest corner from the gear box.
I then blew in.
... nothing at first (and I was thinking what?)... and then that was it; the cavity was filled and pressurised.

So the enclosure can breath, while the motor remains sealed.
Warm air or cold air, the diaphragm will absorb the pressure differential.
This should prevent any ingress of media between the seals and drive shaft.