Can a mechanical E-unit be used with a DC motor with bridge rectifier?

probably, but be careful as the frame on the E unit is common.

Get out the OHM meeter and see if you can isolate the contacts.

( but you probably already know that. )

I'm using one to control a switch on my layout but it's AC.

I'm pretty sure the answer is yes, but you have to be careful with the sequence of components.  I've heard it's possible to magnetize the E-unit coil by passing DC through it, after which the solenoid (plunger) will no longer work reliably.

You might check out a few posts by someone named Lionelsoni on the web forum of 'that other 3-rail magazine.'  

Absolutely.  I have probably 6 or so Williams engines wired just like this. The E-unit IS a DPDT sequencing switch, so it works out perfectly. I'll try to upload my wiring diagram unless someone else beats me to it.

This is not the case. I have a few that have been running on DC for over 20 years w/o fail. If it does become an issue, you can do something very simple to degauss them...

Run it on AC!

However, the circuit I use does not involve the E-unit coil with any DC, only the contacts.

You can also run the coil on AC but put DC on the fingers. 

Pete

Over on another forum the solution was with an AC circuit; to use a bridge rectifier and then use a 'double pole double throw switch with center off'( center off provides a neutral) to change the polarity of the wires going to the motor after the rectifier. Do not put the switch before the rectifier as it won't do anything to change the polarity in an AC circuit.

Lee Fritz

I think that was my post - and the Lionel E-Unit IS a double pole double throw switch with center off sequencing switch.

All this to avoid a modern, reliable $39.00 Dallee reversing unit? Let me take the FI off

my car and install a carburetor instead. Yeah, that's the ticket.

Sorry. But, really.

No, I think it was because he already had E-units and rectifiers on hand. Sometimes it's just more fun to experiment with stuff on hand.

I've done it a number of times. You still have all of the fussiness of the original E-unit, but the loco runs better with a can motor.

Years ago this was common. Williams provided these diagrams:

quote:

All this to avoid a modern, reliable $39.00 Dallee reversing unit? Let me take the FI off

my car and install a carburetor instead. Yeah, that's the ticket.

 

Sorry. But, really.

I didn't know e-units were so unreliable. They seem to work fairly well for me.

Late to the party but yes Brian as some have said in this thread along with picture that

Reading Fan posted of Williams Engines wired in such that fashion.

Have 4  of the FM Williams Trainmasters made in 1980 some with some without the e-unit and they are brutes with their large pittman motors and magnets seen under each power truck for great pulling power.

If yours ever run erratic chances are the bridge rectifier is bad or on last leg as this happened

on 2 of mine that i replaced and back up and running normal.

Pure simple fun.

Glad to help. Williams Reproductions began about 10 years before electronic reverse units were introduced. Lionel E-units were the preferred option.

Early QSI instructions explained how to cut a connection on the bottom of the board of an ACRU (AC Reverse Unit) and use a bridge rectifier to supply DC to can motor(s).

I vaguely recall that Williams wanted to install his own reverse unit inside the silver GG-1 for the TCA 25th Anniversary [Madison] Set in 1979 but it didn't work. E-units were purchased from MPC instead.

Back then, lots of people tinkered with what they had on hand - just like Brian Olson's original message.

I bought an MTH Miami Dolphins steam locomotive at York a couple years ago that that someone had wired up an E unit to a bridge rectifier in it so I know it can be done.

Jerry

Again, thanks for all the information. Really looking forward to getting back home and tinkering. 

Charly could really use a diagram to speed a deal along. So if some could pull one from their bag of tricks, that would be nice.

  I'm anticipating her need, and know she's busy today, so thought I'd post the request on my own.

  EDIT: I made up a little DC on AC E-unit diagram myself, and posted it in her thread here