Mth smoke problem

Clem,

 

You need to remove the engine shell to gain access to the smoke unit motor. You need to put a drop of oil on each end of the motor shaft.

Good morning Joe

 

I have it apart, but there is no way to get at either end of the motor shaft. Do I pull the fan off? the other end is sealed, a removable plastic cap maybe?

 

Clem

Clem,

You'll need to take the top of the smoke unit off and remove the impeller with a pair of needle nose pliers. That'll give you access to the bronze bushing in the motor. You don't need to oil the other end. If you try to take that end off the whole motor will fall apart. Also when you put the impeller back in make sure it's down far enough on the shaft so that it doesn't hit the top when you put it back together.

Also make sure you put the gasket back in between the two halves or you'll have smoke fluid all over the place.

Ralph

MTH smoke motors have a small hole near the shaft at the bottom of the motor, so if you feel the need to oil it, you can.

 

Good afternoon

 

It doesn't squeal anymore, I pulled off the impeller and put on one drop of oil. Thank you for the information. John I never did see a little hole to put the oil in. 

 

clem k

Not to worry Clem, if it doesn't squeal any more, problem solved.

 

For future reference, this is the terminal end of a new MTH smoke motor, see the hole?

 

 

Thank you John   Mine doesn't have that

 

Clem

I checked my stock of new motors and sure enough they have that hole. I do have older ones that don't. I haven't changed a smoke unit motor in a while so I guess I never noticed that.

You'll be fine where you oiled it.

Ralph

I would be careful with that hole since it is near the brushes.  The one that seems to cause issues is the impeller side.  Some smoke unit have access to that bearing with out disassemble.  I think the never stuff doesn't.  G

Oil isn't the kiss of death on the brushes, I know a few people that actually oil the commutator of their Pulmore motors to minimize friction, it doesn't affect the operation at all.

An AC Large pulmore motor and a DC small motor are 2 different beast.  Also for MTH the power is the same power used to power the IC on the PS-2 board.  I would be careful.  The ones I have seen wet, don't work.  G

Smoke fluid and light oil are two different things. Smoke fluid in the bearings of that motor cause the problem, oil fixes the problem, apples and oranges.

 

I dropped 5w-20w oil into a small DC motor brushes I have here on the bench and it had no effect on operation.  It's actually a motor from a car remote mirror, about twice the size of the smoke motor.

Okay, but I am not comparing apples and oranges.  If you want to oil inside the brushes of DC motors go for it.  It certainly is not part of the maintenance requirement for motors.  It will increase dirt pick up, electrical noise and wear if not foul commutaters.  The squeal is a metal to metal friction on the shaft and bearing from a dry or out of round bearing.  G

Well, I don't "want" the oil in there, but a small drop of oil on the commutator end isn't necessarily going to migrate to the commutator.  I was just point out that if oil does get on the commutator, it's not the end of the world.

 

Truthfully, it's always mystified me why mineral oil (smoke fluid) screws up the bearings.  Here's a clip from Handbook of Electric Motors which seems to indicate mineral is a good thing.  I can only imagine what is added for scent is really bad for bearings.

 

That section is quoted out of the sleeve bearing section.  So it requires a load carrying property also.  Normally with seals in place to keep any oil from getting onto the commutator, windings or stator.

 

Theoretically, the bearings in our DC train motors are oilite bushings that should not require lubrication.  The bearing is impregnated and the oil is suppose to move out and into the bearing via capillary action.   G

They seem to require oil, sometimes very early in their life.

 

However, since oil frequently quiets them, I still don't get why the smoke fluid causes the problem.

 

That's a new one for me. In racing slotcars for a long time that's one thing you want to keep off the com and brushes. I've seen people oil that end a lot and it killed the arm. It got all gummed up and over heated the arm. And for slotcars we use a lite oil.

Either way if oiling the top bushing stops the noise then don't worry about the other end. Just my thoughts.

Ralph

All mineral oil isn't the same, "Lubricating" Mineral oils have different additive then lets say Baby Oil Mineral oil.   G