DC Motors for EVs?

Going with a brushed DC motor with separate wires for stator and rotor windings gives you a few advantages. By being able to switch between stator and rotor windings being wired in series or parallel you can virtually have a two speed motor with different top speeds and initial starting torques. Also by reversing the wiring of only one of these two motor windings one can get the motor to move in reverse.

As far as an electric fork lift motor, I would expect that most electric fork lifts use this type of a motor. Now will the electric fork lift you find be this type of motor and be suitable for you? Well that's a question I cannot answer.

Actually, most fork truck motors are series wound. Separately excited motors are fairly rare in EV's and fork trucks, even though they have the advantage that regen braking can be easily implemented. The newest fork trucks are increasing equipped with AC motors (and inverter drives).

For a relatively sophisticated, well thought-out system, Azure Dynamics is a good choice. The motor is AC, which has the advantage of being brushless, and this particular one is also a little more efficient than the typical series wound DC motor.

However...

By far, the cheapest way to go is with DC series wound, and you can find loads of controllers, and all the bits and pieces. In the US, Warp Drive, ADC (Advanced DC), are thought reliable, but there are loads of vendors.

I always recommend that people peruse EVAlbum for inspiration, and that once inspired that they search the archives for info on builder experiences. The album can be sorted by motor type, motor brand etc.

I'd guess that series wound motors are used in 90% percent of conversions. They are not and will not be used in any real production electric cars, however, where AC motors are the norm, even at the low end of the field (with the Reva, from India having made the change a couple years ago.) (In neighborhood vehicles, series DC and lead acids are the norm.) In hybrids, motors have been either AC or brushless DC.

There are some brushless DC motors of a size that can be used in an EV, but they are hideously expensive, and essentially just one step beyond prototype status. (It's not that they are exotic... its just that there has not been a market for them. Suitably optimized, they can be perhaps 95% efficient, instead of 92% for AC and 88% for DC series.) (In use, DC series looks worse, because regen is not realistically possible.) When you do the cost benefit analysis, it is very, very hard to justify anything but DC series -- but don't rule DC separetly excited, if you can find a suitable controller.

Most lift trucks that I have worked on are neither. The armature and the fields are terminated on the outside of the motor case. The can be externally wired to function as series or shunt. I have seen them wire the same size motor in different equipment depending on the battery pack voltage either way but it was rare and on small equipment.

Motor will have 4 terminal bolts on the motor case. Series wound will give you more torque at slow speeds. Which why most lift trucks are wired that way. Don't need them to go fast just move a heavy load. Shunt wound will give better speed control.

If you can find one they all so use a compound motor. Which maybe your reference to series and shunt wound motor. Some had 6 external terminal and some had the shunt field internally wire to the armature. This combines the motors torque at low speed and speed control.

Motor terminal marks for series motor S1,S2,A1,A2

for Shunt motor F1,F2,A1,A2

Compound with 6 terminal will have S1,S2,F1,F2,A1,A2

Another thought, prompted by the other posts and your mention of used fork truck motors. You will probably want a modern controller (some variation on pulse width control, so you are not wasting energy in resistors). If you can find a fork lift motor with matching controller, that would be the cheapest bet by far. Before you commit to a motor, make sure you can find a controller to run it. In general, a controller that runs a sep x motor does not run a series motor.

Here's a link to a US supplier of such stuff -- I'm sure there are similar ones in Ireland and the UK.

I would recommend purchasing a used complete electric golf cart to scavenge the running gear and controller. The golf cart industry has well developed the DC motor + lead acid battery technology, and good running but cosmetically challenged carts can be purchased cheap.

Golf carts have short tires, and with a simple wheel change you can easily tailor the final gearing to meet your intended road speed.

A universal motor is usually the best motor to use if Ur working on a truck since it has the characteristic of the shunt and series DC motors. The DC motors commonly used in cars are the DC shunt motors because of its smooth characteristic in speed and torque. More so it is readily available and affordable when compared to the universal motors.

Dickson

the newer fork lift trucks use ac motors and use ac to power them this way you get better control.

look up fork lift truck and look for ac motors, you can also use these motors for regen braking, thats how they stop fork lift trucks, when you take your foot of the accelorator pedal the motor turns into a generator, and its suprising how good the system is

ps i used to work for atlet fork lift trucks

Could we get any of these kind of motors out of electric forklifts.

That's exactly what I'm using. Including the controller.

Keeping the gearbox and clutch too. Look for a motor which will produce the same ( or perhaps a little better) torque as the OEM.

Fiat Bambino.

Cheers,

Stu