Choosing a good motor

[mbrownn]

I am looking for a series wound or permanent magnet, High inductance, very low resistance DC motor or generator to use for my experiments. I have found a suitable motor but it is only rated at 200 watts and this does not give me much power to play with. I was wondering about the electric motors used in fork lift trucks or permanent magnet DC generators used for welding. Can anyone point me in the right direction to find information on these motor/generators?

[Bizzy]

Motors

hi mbrownn
I found both grainger.com and mcmaster.com to be very reliable with a large variety. They also have a detailed explination of each motor and its general purpose. the down side is that they are pricey. Also they only sell to compnaies not private individuals, BUT you could do what my wife I did. We made up a company and registered under our "companies' name
I hope that helps
Bizzy

[radiantstream]

motor/generator

Hi MBrownn, Have you considered an offical Bedini motor/generator kit from r-charge.com? They draw very little amperage, have great voltage output, and might be useful in conjunction with the type of experiments you're looking at conducting. Here's a LIVE STREAMING video peek inside partdaddy.com, the manufacturer of these kits. ~Steve~

[wrtner]

I am looking for a series wound or permanent magnet, High inductance, very low resistance DC motor or generator to use for my experiments. I have found a suitable motor but it is only rated at 200 watts and this does not give me much power to play with. I was wondering about the electric motors used in fork lift trucks or permanent magnet DC generators used for welding. Can anyone point me in the right direction to find information on these motor/generators?

Try motor car starter motors

[mbrownn]

Thanks guys for the links etc but I need more info, namely the motor inductance and resistance. Car starters have too low inductance for what I need although the resistance is perfect. I suspect the ideal motor will in fact be a high power low voltage DC generator wound something like a universal motor or possibly a dc arc welding generator but its difficult to find the info on them.

[eternalightwithin]

McMaster.com will sell to individuals. Buy there all the time

[mbrownn]

Update

I have spent a good deal of time now researching motors that would be suitable candidates for a Lockridge device. I have been looking for motors with a high inductance/resistance ratio and an efficiency of 70% or better. This has proven to be difficult.

Most brushed DC motors have a relatively low inductance which is not Ideal even though the ratio between inductance and resistance may be acceptable. The next problem is the efficiency, many manufacturers of servo motors quote efficiencies well above 70% but this is under Pulse Width Modulation (PWM).
PWM will under ideal circumstances double the efficiency of a motor so when efficiencies of 85% are quoted then in reality it is closer to 42.5%. If we use the same spec motor for our generator we have now got an efficiency of 18%. To get these motors into overunity we need a COP in excess of 5.5, not an easy task with such low inductance motors.

Hopefully I will find a better candidate in the near future.

[WeThePeople_USA]

Car starters have too low inductance for what I need
although the resistance is perfect.

To bad low resistance with high inductance is the need here,
a homopolar motor would have been perfect for this.

[mbrownn]

To bad low resistance with high inductance is the need here,
a homopolar motor would have been perfect for this.

I can use low inductance but compensating for it means I have to lower the COP and use higher voltage and frequency to bring it back. I want to use normal voltages that are available to everyone so that the system can be built with off the shelf parts as much as possible. With High voltage and frequency any commutative DC motor can be taken into overunity (I believe). Motors built before WWII were bigger per unit power with higher inductance making the job a lot easier.