Need help with gearhead

[u18b]

Hi guys.
I'm new to gearheads and some of you work with them a lot.

I'm rebuilding a brass DD40 for a guy.  The original motors were tossed and the former person who worked on this did a moderately poor job of installing Faulhaber 1016  M  012  G motors in it  with  1406 gearhead.



The problem is that the gear reduction is actually TOO low for this loco.    So the plan is to remove the gearhead.

Question-  how does the gearhead come off?

I see no screws.

When I gently (well, slightly --with some firmness) twist it, it does not unscrew.  Of course I don't want to damage it, so I'm not trying terribly hard.

How do I get it off?

Next question-    I see written on the gearhead   10/1   4:1

What do those numbers mean?   I sort of assume the  4:1 is the gear reduction.

Thanks
Ron

[victor miranda]

ll the photos I have seen show the gearhead itself
is threaded and so it screws off.

I guess it could be loc-tited....
warm it up in boiling water?

I'd try that first because all the parts and plastic should be
able to stand up to the temp. 
most glues get soft over 180-200 degrees.

it works for jars...

victor

[Chris333]

Yep un-screw:

[Chris333]

The numbers mean it is 10mm dia and a 4:1 ratio. That is like a $75 dollar motor if you get a "deal". Probably $150 new.

[u18b]

Thanks guys.  I'll get tough with it.

I feel better now knowing what to expect.

[u18b]

I got it off.  I had to use two pair of pliers.

I did not have to damage the motors or hold them too tight and risk bending them.

They came off easily with pliers.  Turned out it was just past what I could do with my fingers.

[victor miranda]

oh yeah! pliers!
that might work....

 
I bet somewhere in the world there are pliers with rubber covered tips
and curved just right to hold that motor and gearbox.

that way it can be assembled with just the right amount of gronk.

victor

[mmagliaro]

Everything you've read here, I agree with.

The problem is that the motor there is a 1016 M 012 G
meaning it is 10mm x 16mm  and it is a 12 volt motor.

If it were a 1016 M 006 G (6 volt), you could still drive it at 12 volts, and get at least double the speed
out of it.   The 6 volt motors, by themselves, are available from motorman and they are not too expensive (about $29 these days for the ones he sells on eBay).  You should contact him directly, however, and make sure you get
the right one.

Your gearhead will screw right on to the 6 volt motor.  The 10/1 is significant.  It means 10mm, but the 1 indicates the style of pinion that the motor must have to fit the gearhead.  Eldon will want to know that.  But 10/1 is
really common, so I'm sure he'd have 6 volt motors that would screw right on there.

I (and others) have discussed this before, but the reason you can drive the "6 volt" motor to 12 volts is that the voltage ratings are just nominal.  The only limiting thing is the current (and therefore, the heat), and the
rpms that the motor can do before the bearings fail or the internal armature basket physically flies to pieces.
In my experience, neither of those things happens with these motors, even if you drive the 6v up to 12.
To be extra save, I often toss a resistor or a diode or two in there to limit it to 10 volts.  My PRR I1 has one of these exact combinations in it, and running full-out at 12 volts, with 90 cars on it, it still only draws about 120mA,
for a motor with a current limit of 170, so it does just fine.

This is just something to consider.   If your engine is "somewhat" too slow, and would be fine if it
had about double the speed, you might consider keeping that gearhead and going with a 6v motor,
instead of running the motor without the gearhead.  You give up a lot of juicy torque and low-end performance
when you remove that gearhead.

[mmagliaro]

oh yeah! pliers!
that might work....

 
I bet somewhere in the world there are pliers with rubber covered tips
and curved just right to hold that motor and gearbox.

that way it can be assembled with just the right amount of gronk.

victor

I've actually been known to use two sets of vise grips ( )   
Seriously, they have curved jaws, and you can keep turning the screw adjuster in the hangle and then regripping
until you get just enough bite to screw the gearhead off.

Luckily, these are the Faulhaber stainless cases, so they are very tough.   Don't try it with the plastic-bodied
Maxons (some Maxons are also metal and those are strong).

[u18b]

oh yeah! pliers!
that might work....

 
I bet somewhere in the world there are pliers with rubber covered tips
and curved just right to hold that motor and gearbox.

that way it can be assembled with just the right amount of gronk.

victor

Hahaha.

I knew that would get a rise out of somebody.

I was very gentle.  I promise!

 

[djconway]

I get very very afraid when I see the wizards get stumped!

[peteski]

I get very very afraid when I see the wizards get stumped!

Even the wizards started off knowing nothing in all subjects and even now, nobody knows everything. 

[u18b]

Even the wizards started off knowing nothing in all subjects and even now, nobody knows everything. 

That's why I love forums.

Modeling has so many more options for learning with the internet.

[randgust]

If it already has a 4:1 that's a 'good one', its the higher reductions that really get problematic.

I've done both gearheads and direct-drive off of Faulhabers and have had limited success with direct drives and dropping resistors.   The current draw is so low off of the motors that you can do a passable job with a resistor, sorta, but the 4:1 with a higher rpm would be better.  The only reason I've done direct drive is if I simply can't fit in the gearhead.

[mmagliaro]

If it already has a 4:1 that's a 'good one', its the higher reductions that really get problematic.

I've done both gearheads and direct-drive off of Faulhabers and have had limited success with direct drives and dropping resistors.   The current draw is so low off of the motors that you can do a passable job with a resistor, sorta, but the 4:1 with a higher rpm would be better.  The only reason I've done direct drive is if I simply can't fit in the gearhead.

Randy speaketh the truth.   If you do not use a gearhead, do not use a resistor to regulate the voltage.
The problem is that without the gearhead, the motor will work harder and will draw more current.
The motor will be fine, but it will not only draw more current, it will draw current that varies a lot more with
load than when you use a gearhead.  So as you add on cars or climb a hill, the motor will draw more current,
and a series resistor will annoyingly drop a lot more voltage.  So if you choose, say, a 20 ohm resistor,
then when the engine is loafing and only drawing 50 mA, the resistor will only drop  1.0 volt.  But under load,
if the motor draws 150 mA, the resistor will drop 3 volts.  Thus, your top speed will be limited
to whatever the motor can do at 11 or 9 volts.  That's a lot of difference and it can be very annoying.

With the gearhead, the motor draws only a fraction of that current, and more importantly, it doesn't vary
much with load.  So if it draws 50 mA with no cars, it might draw 75 mA with a full train on a hill.  The resistor,
therefore, will drop about the same whether the engine is idle or heavily loaded.

The short answer is... if you don't use a gearhead, and you use a 6v motor,
 use a few diodes in there to drop a fixed voltage,
or, if you aren't going to use a gearhead, just use a 12 volt motor and forget all the dropping stuff.
(much easier... strings of diodes aren't always easy to fit in there).