[Sutripta]

Originally Posted by A350XWB

3-phase AC induction motors are used for traction in modern locomotives.

How similar/ dissimilar (apart from size ofcourse) are these motors compared to our very common industrial 3 phase induction motors. Esp with regard to their torque characteristics.

Regards
Sutripta

[VaidhiR]

WOW. This loco is amazing. Is there a website from where I can order a scale model of this loco?

[A350XWB]

Originally Posted by Sutripta

How similar/ dissimilar (apart from size ofcourse) are these motors compared to our very common industrial 3 phase induction motors. Esp with regard to their torque characteristics.

The traction motors used are similar to the industrial 3-phase induction motors with modification in winding to meet the torque requirements. Principle wise, it's the same. Some trains like the TGV also uses synchronous motors. Some good reads below:
https://www.ee.co.za/article/tractio...comotives.html
http://www.republiclocomotive.com/ac...-traction.html

[Sutripta]

^^^
Am sorry, but the two links have essentially no information on what changes are necessary to make a traction motor out of a 3 phase induction motor. You had mentioned about a change in winding. (Do you mean slip ring induction motors? Those are not really traction motors.) Could you elaborate on that please.

Reason for asking is that the characteristics of an induction motor are well known. And low starting torque is one of them. Depending on application if one does not want specialised motors, it means oversizing the induction motor. With other associated problems of cost, weight, starting etc. So if a winding change can take care of some of these problems, would like to know about it.

Regards
Sutripta

[A350XWB]

Originally Posted by Sutripta

Am sorry, but the two links have essentially no information on what changes are necessary to make a traction motor out of a 3 phase induction motor.

I think I misunderstood your initial question
The speed/torque characteristics are controlled by the Variable Voltage Variable Frequency Drive (VVVFD) that I mentioned earlier (LCC+TCC). You can go through the below articles on Direct Torque Control (DTC) and Variable Frequency Drives (VFD). I think this is what you are looking for.
https://en.wikipedia.org/wiki/Direct_torque_control
http://www.gozuk.com/blog/vfd-basics-864930.html
https://www.ecmweb.com/power-quality...equency-drives

[Sutripta]

^^^
So no special windings for induction motors to turn them into traction motors!

VFDs can be the basic V/F drives or the far more complex vector controllers, both sensor less and with sensor. Nowadays the cost of the sensorless vector controller had plummeted (decreasing cost processing power, faster power switching devices etc) so much that it does not make sense to use a V/F drive for most purposes.

The torque produced is a function of the magnetic flux, which is a function of currents rather than voltages. Which a high quality drive can control. Some drives even boast of greater than 100 % starting torque! (However this has a large number of qualifiers which are not mentioned in the publicity pamphlets!)

Saying all this, controlling a locomotive requires a different level of control. Industrial systems I do know off. Was wanting details of locomotive systems, both from the drive and motor point of view. Esp when there are multiple motors.

Once again the links provided are not really useful. But thanks for the effort nonetheless.

Regards
Sutripta

[A350XWB]

Originally Posted by Sutripta

Was wanting details of locomotive systems, both from the drive and motor point of view. Esp when there are multiple motors.

Once again the links provided are not really useful. But thanks for the effort nonetheless.

I used to work for WDx-4x locomotive control (for one of the two providers who supply the LCC+TCC+Traction motors) some time back, but I can share only the details which are published in the public domain

[Sutripta]

^^^
Alstom I guess.

Regards
Sutripta

[RM Motorsports]

Indian Railways’ Chittaranjan Locomotive Works sets new world record amidst nationwide Coronavirus lockdown! Despite COVID-19 restrictions coming in force on 21 March 2020 across the country, the Chittaranjan Locomotive Works (CLW) has created another record in making the highest number of locomotives. In the financial year 2019-20, the CLW produced a total of 431 locomotives. The locomotive factory, located in Asansol, West Bengal, surpassed its own record of manufacturing a number of 402 locomotives in the financial year 2018-19, which has been recognized by Limca Book of Records as World Record. The production of locomotives by CLW has witnessed a jump of 75 per cent over the last six years from 250 locomotives in 2014-15 to 431 locomotives in 2019-20, under the ‘Make in India’ initiative, states Indian Railways.

https://in.yahoo.com/finance/news/de...081521047.html

[Rahul Rao]

Originally Posted by Sutripta

Saying all this, controlling a locomotive requires a different level of control. Industrial systems I do know off. Was wanting details of locomotive systems, both from the drive and motor point of view. Esp when there are multiple motors.

Locomotives like WDP-4B and WDG-4 have a 8 notch system, to control speed. Each notch tops of at a certain prime mover power level and motors gradually gain maximum possible they can with the power available.
The power and frequency available to each motor is controlled by the microprocessor using speed inputs from seven individual speedometers.
First is a doppler radar based speedometer and other 6 are each individual axle. Motor applies barely enough power to remain at the verge of slip, on a graded start you can here metal on metal scrape, and the train barely starting to move, as it gains traction, frequency and current are both gradually increased to keep wheel slip at 2% till it attains maximum power applied to wheels that the particular notch permits.


Rahul

[Sutripta]

^^^
Thanks. But was essentially wanting more technical details than what is seen by the operator.

Regards
Sutripta

[fhdowntheline]

A little OTT my (maternal) grandfather would have been proud to see this if he were around ! He was amongst the first batch of Railway loco pilots from Central Railway to be selected for the ALCO WDM2 engine conversion program (from steam) back in early 60s. He made copious notes of the training, so much so that his notes were sought after in his division as a veritable manual- at that time, he had an equivalent of a QRH (aviation jargon). I have seen it when I was in my teens.

[tharian]

Came across this video of a perfect crossing of a WDG6g (4 stroke) and a WDG4d (2 stroke) Locos hauling freight trains.

The difference in engine note can be heard clearly.

https://youtu.be/OvI6NFBsVPM