Did a search for this but couldn’t find anything, sorry if there is indeed something and i just didn’t find it.
I would like to know the differences of DC and AC motors.
What are the pros and cons of a DC motor?
What are the pros and cons of an AC motor?
Can a motor in-of-itself be used to use regenerative breaking, or will that require an extra generator/alternator.
Thanks for all of your help and answering my “stupid” noob questions. 
DC motors.
More complex, slightly heavier per power rating and more expensive than AC (by a long shot). Almost all have pesky (well not too pesky!) brushes - carbon pick-ups that pass an exciting voltage to the rotor windings - eventually they spark and require maintenance.
They are however easier (and cheaper) to control than AC. They are slightly more efficient than AC. For regen DC motors require complex regen controllers (expense again).
AC motors. Cheap and plentiful. Will not tolerate as much of a swing of voltage than DC, hence control of same is more complex. They give off more heat than DC (hence may need water cooling or fan-forced cooling independant of the main rotor). They are simpler than DC and as such they rarely need maintenance. In fact about their only maintenance is bearings or when the windings eventually short due to age or humidity - something that equally affects DC windings. AC is cheaper to repair/re-wind.
I think the power curves of AC and DC motors is similar but AC suffers from ‘cogging’ due to the control of this motor which is done by varying the frequency of the supply, unlike DC which is voltage controlled.
Overall AC is more expensive because of the cost of the controller. I’m not sure if this will narrow in time as both use similar electronics components, it’s just that AC control tends to be more capital intensive because there are more parts (and a slightly bulkier controller - I think).
My guess is AC is probably the future. A friend who died a few years back was a world-recognised expert in motor design and he told me 20 years ago he believed ultimately AC would win through.
Long live Edison’s alternating current motors!!
thanks scotchonrocks,
that helps. so basically for a regular car conversion - it really makes sense to go with a DC motor and contoroller.
With regen capabilities, what would be cheaper AC/+controller or DC/+Controller.
How does one differentiate the differnece between a regen and a non-regen controller. Is the Curtis 123C - i think thats the model number - a regen?
[QUOTE=scotchonrocks;3396]
Long live Edison’s alternating current motors!![/QUOTE]
I believe Tesla was AC not Edison.
Noisome
[QUOTE=scotchonrocks;3396]
Long live Edison’s alternating current motors!![/QUOTE]
Edison hated AC, He was so closed minded to it he got left by the way side. Tesla designed the first poly-phase ac motor. Westinghouse was the driving force behind AC.
Hi there guys and gals can anyone help me im tryin to convert a few things that are petrol driven, ive found several parts that i can use but dont no what runs best with what.I want to use 7x12v 33ah sealed lead acid batteries a 72 volt motor geared, but the gearing needs to get a speed of 18,000 rpm, also i want use 3x12v alternaters to charge or use at 36v to prolong the life of the battery pack CAN ANYONE HELP…
[QUOTE=PATZKE;3407]thanks scotchonrocks,
that helps. so basically for a regular car conversion - it really makes sense to go with a DC motor and contoroller.
With regen capabilities, what would be cheaper AC/+controller or DC/+Controller.
How does one differentiate the differnece between a regen and a non-regen controller. Is the Curtis 123C - i think thats the model number - a regen?[/QUOTE]
The Curtis AC controllers are notoriously impossible to cool. Climb a little hill, and they will launch up to about 200 degrees in about one minute and drop to about 10% of their rated output. The DC controllers are easier to cool and far cheaper to operate. The brushes have been improved to last about 5 years under daily driving. I am getting 100+ miles between charges. Regen braking isn’t worth it either. The best use of energy is to keep the vehicle rolling. Pulse driving is the way to get the range, coasting for 40% of the time. No inverter means no onboard cooling required. Budget is about 30% less than AC systems. Use 144VDC systems and you can drop the transformers between the AC source and the batteries, cuting the cost of charging to about 1/3rd that of other voltages. Also, the AC/DC converters are about 1/3rd the cost as well.
when Edison was accused of stealing inventions, he replied “everyone steals, you just have to know how”
I’m not much of a tech sheet guy but I used to have the blue motor in my car with a GE controller and now have an AC motor with a sevcon S6 controller. The difference is night and day. I can hold it to the floor all day, have four adults onboard, going up hill 58mph with the motor turning 9000 RPM and my cooling fans do not even kick on. You can set your hand on the controller and it is not hot. Proof is in the product.
