What Does "Bi-Polar" Mean?

What Does "Bi-Polar" Mean? (HM2G4Z)

Buy flags at Flagstore.com!

N 38° 34.263', W 90° 27.792'

  • 0 check ins
  • 0 favorites
This electric locomotive uses a drive system that eliminates the gearing normally used between the motor and axle. It does this by making the axle part of the motor itself. The armature of the motor is mounted on the axle, and the motor's poles and magnetic fields are mounted on the frames next to them. As there were two of these field magnets per motor the term "bi-polar" came to be used. The geared electric drives of the period were limited by the large size of the motors needed for mainline locomotives. They were difficult to fit into the space available between the frames and next to the wheels. The "bi-polar" avoided this problem although it had a considerable amount of weight not cushioned by its springs. They operated for long and successful careers, but the development of lighter and more compact motors made geared designs universal after WW II. The Milwaukee Road's "bi-polar" was a passenger locomotive. It could haul a 1000-ton train of a dozen steel cars up a 2.2% grade ( arise of 2. feet for every 100 feet of distance) at 25 mph wihtout a helper locomotive, or speed it along at 60 mph on level track. Its maximum safe speed was 65 mph. It ran on 3,000 volts of direct current power. It has 12 motors to drive its 44" wheels, and only the end axles with 36" wheels are not powered. It produced 3,517 HP for short periods. It is 76'

long and weighs 521,000 lbs. New York Central #113, on exhibit nearby, also uses the same "bi-polar" drive, but uses 660-volt D.C. power.
HM NumberHM2G4Z
Year Placed2012
Placed ByMuseum of Transportation
Marker ConditionNo reports yet
Date Added Sunday, April 28th, 2019 at 8:02am PDT -07:00
Sorry, but we don't have a picture of this historical marker yet. If you have a picture, please share it with us. It's simple to do. 1) Become a member. 2) Adopt this historical marker listing. 3) Upload the picture.
Locationbig map
UTM (WGS84 Datum)15S E 721002 N 4272228
Decimal Degrees38.57105000, -90.46320000
Degrees and Decimal MinutesN 38° 34.263', W 90° 27.792'
Degrees, Minutes and Seconds38° 34' 15.78" N, 90° 27' 47.52" W
Driving DirectionsGoogle Maps
Which side of the road?Marker is on the right when traveling East
Closest Postal AddressAt or near , ,
Alternative Maps Google Maps, MapQuest, Bing Maps, Yahoo Maps, MSR Maps, OpenCycleMap, MyTopo Maps, OpenStreetMap

Is this marker missing? Are the coordinates wrong? Do you have additional information that you would like to share with us? If so, check in.

Nearby Markersshow on map
0 miles
0 miles
0.01 miles
0.01 miles
0.01 miles
0.01 miles
0.01 miles
0.01 miles
0.01 miles
MCHX #117
0.01 miles
Check Ins  check in   |    all

Have you seen this marker? If so, check in and tell us about it.

Comments 0 comments

Maintenance Issues
  1. What country is the marker located in?
  2. Is this marker part of a series?
  3. What historical period does the marker represent?
  4. What historical place does the marker represent?
  5. What type of marker is it?
  6. What class is the marker?
  7. What style is the marker?
  8. Does the marker have a number?
  9. This marker needs at least one picture.
  10. Can this marker be seen from the road?
  11. Is the marker in the median?