Need for Speed - Model Train Forum - the complete model train resource
Model Train Forum - the complete model train resource

Go Back   Model Train Forum - the complete model train resource > Scale Specific Model Train Forum > S Scale
Forgotten your password?

S Scale Get in here if you want the lowdown on S scale!


Reply
 
Thread Tools Display Modes
Old 09-11-2019, 02:05 PM   #1
hjstr6
Gang Labourer
 
hjstr6's Avatar
 
Join Date: Jul 2019
Location: Seekonk,MA
Posts: 51
Scales Modeled: S
Need for Speed

I have a question. Why do some of my Locos run faster in reverse? In particular, I have two AF 290's that I rebuilt in accordance with Dave's AF trains Videos. I followed every step. Cleaning, polishing, lubrication, new fingers, finger tension, new brushes, brush springs, brush spring length at least 1", polished & cleaned commutator and grooves, Checked continuity, Isolated E Unit, and one 290 runs perfect in both directions and the other runs faster in reverse. I have noticed this with other locos I have as well. Do some motors run faster in different directions. I've dismantled this loco so many times I can do it blindfolded.
hjstr6 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 09-11-2019, 02:18 PM   #2
cramden
Dispatcher
 
Join Date: Oct 2015
Location: South Jersey
Posts: 1,270
Scales Modeled: S
It's not an uncommon problem for some engines. PortLines has a clinic on their website that addresses the most common issues that may be the cause. You can eliminate some of the tips if you've already done those and zero in on the other tips you may not have done. Here's a link. Hope this helps. http://www.portlines.com/portlinesclinic20.htm
cramden is offline   Reply With Quote
Old 09-11-2019, 02:54 PM   #3
AmFlyer
Dispatcher
 
AmFlyer's Avatar
 
Join Date: Mar 2012
Location: Laguna Niguel
Posts: 1,785
Scales Modeled: S gauge
The idea here is to implement carefully all the cleaning, adjustments and repairs in the clinic. That does not always mean the engine will run at the same speed in both directions. Gilbert made many running changes to the design of their armatures. These changes included among other things the winding direction around the poles (clockwise v counterclockwise) and the position of the commutator slots with respect to the poles. These features affect torque and speed in each direction differently. With the advent of PulMor Gilbert needed greater starting torque and increased armature heat buildup resistance since the motor could stall rather than have wheels slip as w/o PulMor. Changing the position relationship of the commutator slots to increase forward starting torque would reduce forward top speed; it does the opposite when the motor rotation direction is reversed. The large motor was also developed for these reasons.
__________________
Tom
AmFlyer is online now   Reply With Quote
 
Old 09-12-2019, 05:33 AM   #4
flyernut
Yard Master
 
flyernut's Avatar
 
Join Date: Oct 2010
Location: Williamson NY
Posts: 5,445
Quote:
Originally Posted by hjstr6 View Post
I have a question. Why do some of my Locos run faster in reverse? In particular, I have two AF 290's that I rebuilt in accordance with Dave's AF trains Videos. I followed every step. Cleaning, polishing, lubrication, new fingers, finger tension, new brushes, brush springs, brush spring length at least 1", polished & cleaned commutator and grooves, Checked continuity, Isolated E Unit, and one 290 runs perfect in both directions and the other runs faster in reverse. I have noticed this with other locos I have as well. Do some motors run faster in different directions. I've dismantled this loco so many times I can do it blindfolded.
Re-face the armature..Cleaning and polishing alone won't cure the problem.. By re-facing the armature, you remove any small microscopic grooves on the face of the armature, truing the surface.
flyernut is offline   Reply With Quote
Old 09-12-2019, 09:39 AM   #5
mopac
Station Master
 
mopac's Avatar
 
Join Date: Feb 2011
Location: Missouri
Posts: 4,722
Scales Modeled: HO mainly, N, S, O, G
When I first got my 336 it ran same speed forward or reverse. Now forward is faster than reverse. I suspect one of the wires to the plug. They are stranded wires and if some of the strands are broken you will not get full power from that wire.
mopac is offline   Reply With Quote
Old 09-12-2019, 11:11 AM   #6
hjstr6
Gang Labourer
 
hjstr6's Avatar
 
Join Date: Jul 2019
Location: Seekonk,MA
Posts: 51
Scales Modeled: S
Thank you all for your advise. I am going to follow the Portline Repair clinic outline. I have aligned the smoke rod stud aft and the side rod studs forward. No change. Next I checked to see if the axle gear was centered properly. It was. Next I checked the smoke piston gear. Not sure what firmly mounted means. The gear has play in it. I'm sure it has to have some play and I don't like the idea of driving that stud into the smoke gear. Do you drive from the stud side or gear side? I have also noticed some play in the chassis and brush bracket bearings. Maybe that's the problem? The commutator appears to be pretty smooth, but that will be my last resort.
hjstr6 is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


» Visit These Sites:
LGB World

Or Our European Train Website ModelRailForum




All times are GMT -5. The time now is 10:05 PM.


Powered by vBulletin®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.