Hallo Leute, wird hier Englisch gesprochen? Ich lese Deutsch aber sie kaum schreiben kann!
Your advice & suggestions please. I have a problem with my son's Fleischmann BR 360 159 shunter with a pancake motor, it looks about new. Model number 4223. I'd just lubricated the motor and gearwheel bearings and was testing by applying power to the brush caps. It was running nice and smoothly until one probe slipped! Theerafter, the motor just doesn't turn. I've removed the motor, it turns freely by finger, with discernable "cogging". When power is applied, it turns just a fraction and stops. I can feel a strong magnetic field if I try to turn the armature. Current drain is high but not a dead short, though I can't immediately measure it. My meter shows about 12-15 ohms between each commutator segment.
What have I broken?
Helpful suggestions please.

Vielen Dank im Voraus,

Nigel

Hi


Well if brushes - checked? - are fine, you possibly face a problem with the armature winding.
Happens sometimes - get a new pancake is the cheapest.

Or open the Motorbox, find the bust soldering point, fix it and put the motorbox together again.

Alternatively the cummutator got cluttered up with used brush coal. Can be cleaned if You are skilled, altough just a vague hope ....


hth
Markus

Hallo Markus,
Thanks for the reply.

The brushes and springs are OK - they look new. The commutator is clean, is there any way to test the armature with a simple multimeter?

Nigel

Hello,


you should have identical resistance between al tree poles. Can even be mesured if you take brushes out and mesurment things in, then turn the motor by little stepps - 1/3 of a turn each time.

greetings

Ronaldchen

Zitat von NigeB

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Hallo Markus,
Thanks for the reply.

The brushes and springs are OK - they look new. The commutator is clean, is there any way to test the armature with a simple multimeter?

Nigel

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Nigel

Sorry .... should have been more precise.
The insulation gap between the - even very clean and neatly looking blocks of the commutator - could be filled up with used up coal, which causes a malfunction of the motor.

Measuring - since this motor's commuter has a.f.a.I.k three sections - in the three steps as mentioned in the other exchange.


hth
Markus

Hallo Markus,

The gaps between commutator segmments are all clear. The resistance between each one is 15-20 Ohms, but this is a very approximate value.

Many thanks for your input so far.

Nigel

It should not be 15-20 ohms.

They should all be alike. When you measure one motor winding, you actually measure all 3. The one between the 2 commutatator plates in parallel with the other two in series.

If your measurements shows that 2 measurements reads 10 ohms and the last showing 20 ohms, the last coil/winding is disconnected.

Klaus

Hallo Klaus, Markus.

The resistance between all commutator segments is the same, ca 15 Ohms. For example between segments 1&2 = 2&3 = 1&3 = ca 15 Ohms. I compared this with a very similar Fleischmann motor from the 1960's (that loco just about runs!) - the same!

Thanks for you input, I am really keen to get this loco running again.


Nigel

Nigel

Sometimes very strange things happen - lacking contact only under special conditions, although the moter seems to check out fine it malfunctions.
Evidently electric current isn't getting there. I don't think that the magnetic field is breaking down

Well this turns out to be an enigma now - solve it ... or get a new pancake.

good luck
Markus

Just to complete the tale, a new armature was bought for ~€40 - it worked first time ! I compared the new and old armatures - no measurable difference but the old one still doesn't work

Thanks for your contributions,
Nigel