Series motors - pros and cons

Britrailer-

 

Later K-Line MP15's had a series/parallel switch mounted on the underside of the chassis - did your model have this option? If so you could connect the ERR motor leads to the center posts on this switch, giving you the flexibility to run in both series or parallel.

 

Looking over the ERR's Cruise Commander manual there are a few options that might help too. Did you try the "small motor" setting, in addition to the 100 speed steps? Also, is the cruise set to "on"?

 

-John

 

 

Try setting the max speed to something less sonic. You may need to program 32 steps to get this feature.  But you will get more steps in a narrower speed range.

I've rewired several two motor diesels to series, including a MP-15 and two Lionel Rs-3s.  No problems so far and they can run really slow.  I've heard that if you overload them they can stall, but not an issue for me.

The series circuit works great on the K-Line diesels with their 4 traction tires.

 

The only drawback(aside from a top speed reduction from ~160 MPH to ~75 MPH) would be the "open differential" effect if one truck looses traction. That truck would spin free and the engine would stall on the tracks. The 4 traction tires keeps this to a minimum, adding weight helps if it becomes an issue.

Series wiring the motors reduces the voltage in half (with 2 motors) at each throttle setting.   I had most of my 2 motor diesels wired that way when I ran straight DC.   I have wired a few back parallel with DCC.   So if you put 12 volts on the track, each motor would get 6 volts. 

 

Yes when they stall, one truck will spin while the other is stopped.    I never loaded them to the point this was a problem.

 

The slow speed running and starting and stopping was great.   However, if you have a dirty motor, it may still jerk some.

 

 

What about lowering track voltage supply? If using bricks  forget this one. I used to wire my early Williams TrainMasters in series. They ran much better.

This forumand it's members is amazing -thanks for all your helpful input.

I'll be in the trainroom for most of today trying out the advice and let you know how it works.

Job done!

 

I tried the 32 step tip but that just made low speed performance even more sensitive to slight throttle increments.

 

Checked the impedance of both motors and they read identical numbers on my digital multimeter so I connected the motors in series.

 

Took a deep breath, hit the "start" button and opened the throttle to step 1 and the engine sound increased with no discernible movement. At step 2 the MP-15 moved off at a slow, majestic pace with gentle acceleration and no wheel slip as I advanced the throttle. I tried a 15 car freight consist and this too worked well.

 

My thanks to you all for the help and information.

 

The 32 step tip will only work if you set the stall voktage and the maximum voltage. That effectively compresses the 32 steps within that voltage range.
If you can do that with 100 steps it is even better.
If you do not set the maximum voltage than you will actually increase the issue by a factor of three. I know this works with the Cab-1 because I have a Mp15 converted to TMCC with an ERR board and a conventional one. Retiring to Series improves the running but even then I can still launch this speedster.

Setting maximum voltage whether in relative or absolute steps is the key.