The eternal question, once again! Getting rid of E-Unit noise !

Do you want to keep the Geep original in the sense that you want to repair the original E-unit, or do you mean that you don't want to change to an electronic E-unit?

You can add a diode in series with the E-unit coil, which would be a very difficult to see addition.

You can find another E-unit from the same era that doesn't make quite as much noise.

No digital E units, if at all possible.  No way to know how noisy an E unit is 'til it's in place, so getting someone else's disaster is pretty risky at best.  Want to de-tox the one I have now, if possible !

Since keeping originality is important, you can just compromise and bypass the original E-unit by disconnecting the wires & leave it installed in the frame and just use an electronic reversing board.  That way your e-unit buzz noise is gone, don't have to worry about variables like whether or not the buzzing noise would repeating itself if you just replace the original with a similar one, etc. and simply not have to worry about again, and you can easily revert it back to the old E-unit anytime you want to.  I would argue that the result would also be directional control that is more reliable to boot.

Seems reasonable to me; no target practice necessary, which the end result would result in a far more irreversible problem of deviating from originality.

I may have to do this...but in that case, which board would fit in the available space? Keep in mind that I'm using the original horn and relay....which works quite well, and has the original sound, FWIW.  Thanks 

Electro-mechanical E-units buzz because there's AC going through the electromagnet. The shifting phase of the AC -- i.e., the polarity reversal -- causes the buzz.

You can eliminate the buzz by connecting the coil leads to the +/- terminals of a bridge rectifier and connecting one AC lead (~) to the pickup roller and the other to the chassis. Leave the other connections wired as-is; just connect the coil wires to the rectifier. The E-unit will function normally without buzzing. While you have it open, spray some contact cleaner in the E-unit plunger to clean it out as they sometimes get sticky over time. 

Do you have the Radio Shack # for the correct bridge rectifier unit. This sounds like an awesome idea, and not too expensive or complex. Thanks ! !

A problem with using a bridge rectifier on the E-Unit is it'll draw more current running on DC, and it's likely to overheat without some voltage limiting.

It's also more likely to get magnetized and that will increase its tendency to stick when being cycled.

Do what Matt stated.  I have done that for 40 years and it works perfect. 

That happened to me back in the 1950's.  I tried to run an E-Unit on full-wave DC, and the plunger got stuck magnetically inside the solenoid coil.  I had to change it back to AC to demagnetize it.

/Ralph Platz

If you want to buy a rebuilt E unit look on www.choochooauctions.com under Lionel listing, as there is a person who rebuilds the E units and sells them. This way you can keep your older Lionel as close to original as possible.

Lee Fritz

I've heard of the magnetizing issue before, but I've also got the means to spring load the plunger so as to eliminate that problem, if needs be.   

Can you describe what you do in order to spring-load the plunger in the E-Unit?  Does it require dis-assembly and re-assembly?

I once put a small rubber bumper in one to see how it would work, it made it a lot quieter, though not totally silent.  It required disassembly, of course.

I can attest to Ralph's contention that they'll get magnetized, I've seen it.  The good news is running the coil on AC again fixes it.

I've heard that's possible, but my understanding is it takes quite a while and a lot of cycles for the plunger to become magnetized. Pinball machines with DC playfields have run through thousands of bumper/flipper/eject hole/thumper cycles without the solenoids sticking.

What can I say, I did the mod for a couple folks and later they came back with problems.  Took the rectifier out and a laps cured them.

I did notice the coil got pretty warm with the bridge as well, but after sitting for about half an hour on a test track, it didn't appear to get hot enough to damage it.

The buzz is caused by the coil and plunger vibrating because the pawl that pulls the toothed gear is not firmly held in place with the teeth of the gear.  You can minimize or eliminate the buzz by CAREFULLY bending the pawl so it has a different angle at which it hooks and pulls the toothed gear.  Try making it more of a hook shape - bending the part that hooks into the tooth upwards a tiny bit. When you do this, bend it half of what you think might be enough.  If you are successful, you'll have a quiet E-unit - without having to replace the e-unit.  I have several e-units that are difficult to hear in neutral.

Dale

If I understand you correctly, the pawl is mainly responsible for the racket, and that would be the source of the vibration.  Easy enough to find out, Gonna use some grease on the bottom pin to de-animate the pawl a little and see what transpires.  Thanks for the idea !

I wouldn't say its the pawl.

On later e-units the top of e-unit has a cone shaped coil stop, and the plunger has a matching depression.  I suspect the noise is generated when the plunger cannot pull up tightly against the stop.

I'm very reluctant to bend the pawl as that can also cause the E-Unit not to properly index.

The noise comes from some kind of mechanical vibration caused by magnetic pulsations.  The magnetic pulsations are caused by the continuous alternations of the AC power applied to the coil -- rising to maximum voltage in one polarity, then collapsing to zero, then rising to the maximum in the opposite polarity, then collapsing again to zero -- all at the rate of 60 times per second.  The magnetic force generated in the solenoid is consequently pulsating.

The resultant mechanical pulsations could be transmitted into the air (as sound) from multiple locations -- from the pawl, from the plunger, maybe from the the frame to which the E-Unit is attached, ... 

Maybe the vibrations can be reduced by mechanical damping methods, but I would not know where or how to do this.

The vibrations could be reduced by applying full-wave DC to the solenoid coil instead of AC: the change in the pulsating magnetism would be less "dramatic" since it would be unidirectional.  And an electrolytic capacitor could be used to reduce the DC voltage variations.  But, as others have already pointed out, the use of DC will increase heat in the coil, and can result in magnetizing the plunger and making it "stick".
 
/Ralph Platz

So, are you saying the only way to effectively get rid of the noise is to use D.C.?

Why are some E-units noisy, while others are quiet?

1) All E-units (running on AC) have the magnetic pulsations, and (in my experience) they all generate a humming or buzzing noise to some degree.  Whey some are louder than others I cannot explain -- too many mechanical variables here.

2) The only way to eliminate the root-cause of the noise is to eliminate the magnetic pulsations.  To do this fully would require powering the E-Unit with pure, filtered DC -- which would generate a different set of problems.  And doing this only for the E-unit (without affecting the AC supply for the motor and lights) would require insulating the E-Unit frame from the chassis.  Not a really practical solution.

3) Mechanical/acoustic dampening may help to suppress the noise -- if one knows where and how to apply it.

/Ralph Platz

Actually, it's very easy to power the E-Unit on DC, you just lift it's coil wire and generate DC from track voltage.  I've done this several times, piece of cake.  A diode or diode bridge and a decent sized electrolytic cap and the job is done.

All the other issues you point out are still in play, magnetizing the core, and overheating due to the fact that the DC resistance is considerably lower than the AC impedance.

jaygee, I'm sure that I might offend the few, this is ok. Is this your first time as the owner of a problematic E-Unit? I'm just a little puzzled. I'd better be good and go back to my corner. This thread is turning out to be good reading anyway.

quote:

1) All E-units (running on AC) have the magnetic pulsations, and (in my experience) they all generate a humming or buzzing noise to some degree.  Whey some are louder than others I cannot explain -- too many mechanical variables here.

So, excessive noise can be caused by the plunger not making firm contact with the stop.

You could also check to see whether any of the staking has loosened.

Thank for clarifying this.

(In my previous reply I had forgotten that neither wire of the E-unit's coil is "grounded" to the frame.)

/Ralph Platz

Ralph, one wire is at frame ground, but you just use that as DC common for the mod.  You can't use a bridge if you have a grounded pin, but you can use a single diode and a cap.  The bridge needs both isolated, as you correctly observe.

The diagram below shows that both wires of the E-Unit's coil could be unsoldered from their normal connection-points and then connected to the "plus" and "minus" outputs of a full-wave bridge rectifier.

One of these wires normally goes to a connection-point in common with the center-rail pick-ups, the headlight lamp, and the power feed to the rotating DPDT contacts (which the plunger&pawl turn).

The other wire goes to the "E-Unit Switch", which (when "opened") deadens the E-Unit and prevents it from acting.

/Ralph Platz

Good point, and you're correct.  I keep forgetting the switch as I never had occasion to want to run without an E-Unit.  Now I rarely have occasion to want to run without a Legacy or DCS remote in my hands.

For several years I have been enjoyed running trains from the Legacy hand-held controls.  But now I am realizing that if I try to run more than 3 trains simultaneously, my brain and fingers can't respond rapidly enough up with the need to change the "Id" numbers on the hand-held units for controlling the specific trains -- even when I have access to 2 hand-held units.  So now I am inclined to go back more frequently to conventional transformer controls, because it's easier and faster to go from one transformer's handle and buttons to another's than it is to remember Id #s and key them in quickly enough. This problem gives me a renewed interest in what might be accomplished with modifications to traditional E-Unit wiring for conventional control.

/Ralph Platz

You just need remotes that are shaped like transformers.

I installed a 4 amp 50 volt full wave bridge rectifier Radio Shack part #276-1146 in a 2346 B&M Geep a couple of years back. Haven't had a problem yet. I think the part was two bucks.  Rich

I had noticed that some of the older, pre 1950, e units seem to run very quite compared to newer units.  These older, quite, e units appears to have the coils wound with a layer of paper between each wrap of coil wire. It is a lot of work to take a e unit apart, but I always wondered it the coils could be VPI treated to reduce noise. I have VPI treated large reactors in the past to reduce noise and it was very successful. 

Now that is an idea.

I wonder how much effort would be involved in taking the works from a CAB-1L remote, and fitting then into a CW-80 shell, with a keyboard and possibly even a small display to show the ID in use. 

quote:

I had noticed that some of the older, pre 1950, e units seem to run very quite compared to newer units.  These older, quite, e units appears to have the coils wound with a layer of paper between each wrap of coil wire. It is a lot of work to take a e unit apart, but I always wondered it the coils could be VPI treated to reduce noise. I have VPI treated large reactors in the past to reduce noise and it was very successful. 

Those e-units have a brass sleeve in the center, and no coil stop.

Way back in time when I was in college getting my electrical engineering degree and when I thought I was smart, I put a diode in series and a cap across an e-unit. Sure quieted it down, but it got HOT!

I marvel at your ability to hold out. Eventually I capitulated and now enjoy the benefits of a command control, and still at times wonder if I should switch to S gauge with Kadees.

To answer the above question....This is the noisiest E unit I've ever encountered, out of zillions of them, over the years... and even with grease on the pawl spindle contact points, and some LSA on the plunger, she's still making noise at an unacceptable level ...phew !   Question...which component is heating up in the DC rectifier conversion?  The coil or the rectifier/ or both ??? Thanks for all the great ideas, gents !

The coil heats up.