Is there a way to find the maximum voltage and or amperage that an electric motor can handle?

[G+_Ben Reese]

Is there a way to find the maximum voltage and/or amperage that an electric motor can handle? We've got a Kid Trax quad that has always been a bit underpowered and I'd like to swap out the single 6v for two 6v batteries in series (12v total). Any risk of burning up the motor or is the only risk bucking the kid off? Do you think an 18v Dewalt battery would be too overkill?

[G+_Fr. Robert Ballecer, SJ]

Slowly increase voltage until it stops moving.

 

Then buy a new motor. :)

[G+_Ben Reese]

Hehe there's always that... I've got a broken cordless drill. I guess if the gears could hold up I could throw that in there. Would it be unreasonable to think the motor could handle higher voltage?

[G+_610GARAGE]

Maximum motor amperage can be a bit of complicated. Motors can handler large amperages for shorter amounts of time. Think of a car starter, it can handle turning the engine over for a couple of minutes. But if it runs too long, the motor burns up. However, if you were to decrease the load, the motor would run a lot longer with no ill effects.

 

My best guess is that the motor will be fine since you are not increase the load on the motor. But the best way to find out would be to test it. Keep an eye on the motor and make sure it doesn't get too hot. If it does get hot, you could try to add cooling. Like a fan (if there isn't a fan on the motor already). You may also find that it runs fine for 15 minutes, then needs a 5min cooldown period.

[G+_Ben Reese]

Thanks. That's kinda what I figured. Right now it doesn't run much longer than 15 minutes anyhow, so I'll probably be getting an extra battery regardless. We just got a power wheels police car at a garage store, so I'm thinking it will need a Raspberry Pi and bigger speaker hooked up for the siren ?

[G+_Eddie Foy]

You don't control the amps.  (yes there are constant current circuits, but not used in many places) The motor takes what it needs.  Voltage is what you control (and with 3 phase motors the frequency fed to the 3 phases).  The voltage the motor can take is based on the windings.  The gauge of the wire and the insulation of the winding wire.  You should be able to safely increase the voltage 10-15% as 610bob mentions controlling the heat allows higher voltage to be used.

[G+_Ben Reese]

That's right. Correct me if I'm wrong... So the motor actually defines how many amps it requires from the battery depending on the load it's under.

Heat is the enemy of any electronic and more power (primarily wattage based I presume?) that is put/allowed through the wire the more heat the wire produces. Since the motor is most likely using mag wire with polyurethane (or something similar) as the insulator, the wire itself can likely handle several times the current voltage. So, it really just depends on how many windings there are which would define the overall resistance of the motor and the amount of amperage it requires. And I presume the highest amperage requirement is when the motor is stalled or held in one position.

 

Am I completely off on any of that?

[G+_610GARAGE]

Ben Reese Yea. This is the way that I understand permanent magnet motors to work. Higher voltage means that the coils inside the motor can produce a larger, stronger magnetic field. Force on the motor decreases the magnetic field. The reduction in the magnetic field reduces the resistance across the coil which cause more electrons to flow into the coil. This inflow of electrons increase the magnetic field. This increased flow of electrons is what we measure as amps. 

 

Basically, the motor tries to sustain a magnetic field, drawing more amps to compensate.

 

This is why an increase in voltage may not harm the motor. If you don't over torque the motor, the windings won't need to draw very much current to sustain the magnetic field. Technically, if the amount of load stays the same, high voltage may lower amp draw a little.

 

I could be completely wrong on what I just said, but that is just how I think of it in my head.

 

Stall current, or rotor lock is the maximum amps that a motor can draw. But most motor aren't designed to handle this amount of current for more than a couple of seconds.

[G+_Ben Reese]

610bob? hehe. I know just enough about electrical theory to be dangerous.

 

I should have prefaced by saying that I built power transformers for a couple years, but never got into the design much. We built several different products varying from 3-phase transformers with copper bands instead of wire to generator transformers with ~14awg to some that put out thousands of volts for printers. It was a fun job, but I wish I learned more about the actual workings of them.

[G+_Jason Marsh]

Take the two toy cars and use both motors to provide the driving torque, build an overdrive geartrain or use taller drive wheels to add speed, and use a 12v marine deep cycle battery to replace the 2 puny 6 volt batts.

 

Then you can add a head unit and outdoor speakers for some tunes, and some real warning lights. Five-O got a bangin new ride!

[G+_Ben Reese]

Jason Marsh? - that's been done. Check out the forums at modifiedpowerwheels.com ?

[G+_Jason Marsh]

PowerWheels moddin', Like A Boss!

[G+_Ben Reese]

I'm jealous of some of the time those guys have!