Good morning all
I have a question. On AC locomotives are the traction motors DC?
Thanks
Lee
They're AC.
Here's a bit of discussion:
http://www.republiclocomotive.com/ac_traction_vs_dc_traction.html
Ed
An AC locomotive has AC traction motors - similar to those on large fixed power tools. Control of speed is done using the equivalent of a 1:1 scale DCC system, which provides very precisely tailored AC to those motors.
A DC loco uses wound-armature motors, commutators and brushes - an overgrown version of the motors in our model locomotives.
Interestingly, both start with AC - from the alternator driven by the prime mover.
Chuck (Modeling Central Japan in September, 1964 - with diesel-hydraulics)
And just to confuse the issue, the GP38AC actually has DC traction motors. That results from the brief transition period in which they were built. In this case the "AC" refers to the main alternator, since the standard version still had a main generator, and traction motors remained DC. By the time EMD's -2 series came out, main alternators were universal in new construction, at least for road locomotives. AC traction motors were still years away.
John
cx500 And just to confuse the issue, the GP38AC actually has DC traction motors. That results from the brief transition period in which they were built. In this case the "AC" refers to the main alternator, since the standard version still had a main generator, and traction motors remained DC. By the time EMD's -2 series came out, main alternators were universal in new construction, at least for road locomotives. AC traction motors were still years away. John
True for mass-market diesels. GG1s were 'pure' AC from the time Old Rivets first raised pantograph to (AC) catenary. There were probably other AC straight electrics as well.
Chuck (Modeling Central Japan in September, 1964)
I did not know the G's were pure AC. Interesting. Here's an interesting chat on the matter:
http://members.localnet.com/~docsteve/railroad/gg1.htm
I believe the motors in the G's couldn't do the "clever tricks" of current AC locomotives.
Mainly because of such low frequency. 25Hz might as well be DC, but they also didn't have the sophisticated control systems thaty do today for controlling AC motors.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Anecdote: I kid my father (retired electrical engineer) all the time that AC is nothing more than alternating DC at 60 cycles per second (wall outlet power). In truth, power is power, electrons are electrons, etc etc.
The best rebuttle he came up with was "DC has no negative side (when seen visually on a scope), so it cant be". I told him if he wanted to see the negative side of DC.... all he had to do was switch the leads on his voltmeter!
Good morning all.
I just noticed that this discussion was brought up to date, and that I hadn't thanked everyone for their input. My bad.
I do thank you all, I find the information very interesting. Even as a kid I always wanted to know how things worked. Which did get me in trouble, time to time.
Have a good day