Get the "Buzz" out? - Pullmor E-Units

[toolmandan]

Hello!  I was wondering if anyone knows a trick for quieting the "buzz" given off from the pullmor e-units?

 

[lionelsoni]

A small bridge rectifier just upstream of the e-unit coil may do the trick:  http://www.radioshack.com/product/index.jsp?productId=2062581&filterName=Type&filterValue=Rectifiers.  If it doesn't quiet it completely, you can put a little capacitance across the coil.

[Lionelking313]

There was an article in the September issue of CTT I beleive for this service.

 

 

[nickaix]

Bob,

I had been thinking about doing something like this, but wouldn't feeding DC to the coil eventually lead to residual magnetism?

[toolmandan]

Thanks for the information!  I have to admit, I'm really a novice at this.  I've seen pictures of capasitors installed across the brushes, but then I read an article about polarized and non polarized capasitors.  You mention a bridge rectifier but there are four leads on the one shown but I have no idea where they go.  I'm really corn-fused!    

Thanks!  

[lionelsoni]

My locomotives run on DC, both the motors and the e-units; and I have not noticed any particular problem.  E-units do stick sometimes, whether run on AC or DC; but I am convinced that this problem is mechanical, not magnetic, and can usually be cured by smoothing out the notches that the pawl creates at the root of the drum teeth.

Wiring the bridge rectifier is easier than finding a good way to mount it.  Disconnect the coil wires from their present attachments and reconnect them to the + and - terminals of the rectifier.  (Polarity doesn't matter.)  Then connect the two ~ terminals to the points that you removed the coil wires from.

[toolmandan]

Thank you Bob!  I'll give that a try.

Dan

[SantaFe158]

Shut it off when not in use? ;-)

[TRAINCAT]

.Bob Nelson knows more than I ever will, but I have a train repair buddy who has figured out a way to quiet the E unit significantly, but not stone quiet, without going to DC operation. Seems to have to do with how well you press the sides back together after repairing it. Mine are nicely quiet now.

Roger