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Carter05
08-26-2008, 11:41 AM
I recently came across some 130v dc motors. They are small little guys only pulling about .5 amps so I would believe they can be used with regular batteries. Now my question is how to drive them for a robot? Most DC motors are 12v or below, so do you know of any small 130v dc motor driver out there?

fitchett
08-27-2008, 09:42 PM
130V DC motors? That seems a little strange. Do you have a datasheet / part number? It sounds like a motor designed to be run with a constant current chopper drive.

Chester

robot maker
08-28-2008, 01:15 PM
one problem is the power source 130 volts meens you need alot of batteries or dc to dc stepup circuit,then i am thinking stall current will be super high
they make 90 volts dc motors,never heard of 130 volt motors
you can make a h-bridge design at 130 volts with high voltage mosfets

Adrenalynn
08-28-2008, 01:54 PM
Actually, stall current should be lower. Watts law.

ScuD
08-28-2008, 04:04 PM
I have heard of 130vDC motors, even higher than that. They're used in lower-end metalworking tools, such as mills or lathes given the relatively simple way of adjusting speed while keeping quite a nice amount of torque (pwm).

The biggest problem lies indeed in getting a high voltage from batteries. You'll need to build a boost circuit which will increase the voltage, and as Lynn said following Watt's law, decrease current. (btw that's why the electric network uses high voltage, to keep currents 'low' so they don't need to put up tons of cable)

Personally I don't think it's feasible to use high voltage motors in robots, unless their efficiency is so massive that they overcome the pricetag / difficulties you'd have to obtain the same amount of torque / battery life with lower voltage motors.

Adrenalynn
08-28-2008, 06:31 PM
Nod. I tend to think the cut-off probably lies somewhere in the 48v neighborhood realistically. And that for pretty specialized applications (combat bots, for example) where the larger range of control is helpful

Carter05
08-28-2008, 07:53 PM
Yes price may be an issue for some but I got these for free and I have about 3 big UPS batteries FULL of 12v lead acids that I also got for free :D So I just want to see if I can use them for anything.

Adrenalynn
08-28-2008, 07:56 PM
Any printing on the motors at all? Anything that would help identify them?

Most likely you're going to end-up designing and building your own motor controller at the minimum...

robot maker
08-28-2008, 10:00 PM
yes you are right i was thinking of 12 volt motors
wont be too hard to make a stepup converter ,maxim make alot of chips for that
i made some of 3000 volts for testing and calibrating meters and some 200 +/- supply for ac ultrapure sinewave source for ac testing,will need high voltage mosfets,then the same for h-bridge design,if you need a circuit leave a message for me,if you follow that route
but really why not use a 12 volt motor ,lot easy to use and not waste any power and other problems,emf might be higher,i never tested it but?
comparing 12 volt to 24 volt motor it was a little higher,so with 10 times the amount it should be higher too

Actually, stall current should be lower. Watts law.