On a F7A The 3 M. U. need scrap at the lead put in M. U. 27

Owen S. Paulsen · **Posted:** Sat Sep 14, 2013 10:32 pm

The is so you can standard AAR which is to 27 M. U. so all GE and EMD , And the F7 did not a limit 4 the train.
This rewire in engineer space at take Brake Control and Selecter Switch.
This Load Resistor need a wire To/From it.
The leads for 3 M. U. that label FB and FC a gone alone relay an method for 3 M. U. connect.
Has a way get a Standard AAR from with alone 27 M. U. a can to GE and EMD I will be grateful.

Owen S. Paulsen
o.paulsen@sbcglobal.net

filmteknik · **Posted:** Sun Sep 15, 2013 1:32 am

I don't suppose this diagram (split in two files) would be of any help.

http://gelwood.railfan.net/manual/f7chart6a.gif
http://gelwood.railfan.net/manual/f7chart6b.gif

Steve

NH0401 · **Posted:** Sun Sep 15, 2013 1:13 pm

AAR MU cable wire assignments

1.. Power Reduction

2.. Alarm Bell

3.. "D" Governor Solenoid

4.. Negative Voltage Common

5.. Emergency Sand

6.. Generator (Main Alternator) Field

7.. "C" Governor Solenoid

8.. Reverse

9.. Forward

10. Wheel Slip Indicator

11. Spare

12. "B" Governor Solenoid

13. Control Circuits and Fuel Pump

14. Spare

15. "A" Governor Solenoid

16. Engine Run

17. Dynamic Brake Control

18. Spare

19. Spare

20. Dynamic Brake Warning

21. Dynamic Brake Interlock

22. Air Compressor Control

23. Manual Sand

24. Dynamic Brake Excitation

25. Headlight

26. Ground Relay Reset

27. Spare

Owen S. Paulsen · **Posted:** Sun Sep 15, 2013 7:24 pm

The http://gelwood.railfan.net/manual/f7chart6a.gif and f7chart6b.gif DONT SO ANY The unit can do want I need.
In the Engineer Stand in a do it the right hardward for and next to is a 1 to 4 Switch to Select 1 the 4 on FB an FC on EMD type for trail unit of 3 EMD the has same 3 M. U.
like a early GP-9 ,GP-7 which be tie the F7A.
The problem that 3 M. U. was EMD design only at cover first 4 unit.
The AAR Standard put wiring in 27 M. U.
This allow the rail to have 6-8 loco a EMD an GE mix.
The problem in that old (before AAR) would not go a GP-9 that has an 27 M. U.

The GP-9 as 8 level for run 1-8 an amount is determine by 27 M. U.
The F7 in a new for Engineer Stand.

Owen Paulsen

Jdelhaye · **Posted:** Mon Sep 16, 2013 10:10 am

As far as I can decipher, he is trying to get an older EMD which is still equipped with the obsolete field loop dynamic brake control ("3 EMD" probably referring to the # of conductors in the field loop cable) to MU with newer style "P-Wire" dynamic braking (which he refers to as "AAR" or "27 wire") units.

Jeff