Ni-Cads & Brushless motors ????
 

I have a few brushless motors, but i have never used them, but I want to build something a little different, But need to know if I can use the brushless motors with a Ni-Cad without having to use a ESC, I just want to use an on off switch, but the motor has 3 wires, batteries have 2 & I don't have a clue if it can be done, & I don't want to damage the new motors I have, can anyone help me or have any ideas ??
Thanx

RE: Ni-Cads & Brushless motors ????
 

Have to use the esc, and the ni-Cads are going to drain FASTTT

RE: Ni-Cads & Brushless motors ????
 

I wouldn't suggest using Ni-Cd batteries. They cannot supply enough volts/amperage to power most brushless motor. Usually NiMh batteries are a minimum, but they drain sort of quickly too. and i think if you don't use an esc, you might be burning up the motors fast. the esc is what controls the power going to the motor. so the motor would either be at full speed or off. i wouldnt suggest using one without an esc. someone else chime in if im wrong or forgetting something.

RE: Ni-Cads & Brushless motors ????
 

A brushless motor is an 3 phase motor. Without the use of an esc you might as well connect a piece of wire from your + to the - leads on your battery for the same results.[X(]
[link=http://wiki.answers.com/Q/What_is_mean_of_Dead_Short_in_Electrical_Term]Dead Short[/link]

RE: Ni-Cads & Brushless motors ????
 

Just run a sensorless esc/motor combo, close enough to an on/off switch.


Seriously though, my first question would be "why"?

RE: Ni-Cads & Brushless motors ????
 

yup
Even a NiCd on a BL ESC will prolly die a fast death just look at how hot some NiMh's get that can't keep up with the current pull. NiMh's have a way higher discharge rate than NiCd's too.

RE: Ni-Cads & Brushless motors ????
 

as mentioned before you MUST have a BL ESC to run a DC motor, all the "magic" happens in the ESC, a non-sensored BL motor is just a bunch of magnets and bundled wire, the esc has to pulse the coils to attract and repulse the magnets, a houshold fan motor is almost wired the same as a RC motor, only the AC 60Hz pulse from the powerlines acts as a esc, you run a fan on 120V DC, expect a fire! (with acception of a few really old AC/DC fans (band pun) that operate like a starter motor (without the solinoid)

RE: Ni-Cads & Brushless motors ????
 

What are you wanting to do withit??

RE: Ni-Cads & Brushless motors ????
 

Thanx to everybody for the input, I am a total Dumb Ass with elec-Trickery, & brushless motors :( (give me a combustion engine & I'm happy)
I just need to know how to wire up the motor, directly just using a battery & switch for on & off, that is if it can it be done ?
Could I just connect the red + & Black - like a normal brushed motor ? (whats the 3rd yellow or white wire for) The motor will be used in short bursts from 5 to 15 seconds. Would I need a capacitor/resistor to stop the motors burning out with instant full load when the switch is turned on ???? I know you are all thinking ***, but I will tell & explain all, when or if I get it sorted, I hope I can as these motors RPM are a lot higher than brushed motors.

RE: Ni-Cads & Brushless motors ????
 

You cannot wire the motor that way unless you want to smoke it instantly. The brush less motor has no brushes as the name indicates. The controller send the current to the right wire at the right time, and the thing turns.

If you want to connect directly you have to use a brushed motor.

Remember: NEVER EVER IN YOUR LIFE will you try to use a brushless motor w/o a controller. Start re-thinking your idea, but this time include a controller. OR, sell the brush less motor and get one that has brushes, and need no controller.

Gerry

RE: Ni-Cads & Brushless motors ????
 

Think of a BL motor as a combustion engine. The Bl motor has 3 phases, the combustion engine has timing. Each one needs to "fire" in the right order for the motor to spin/turn.

In order for you to get the BL motor to spin you would need to attach the battery to 2 of the wires to activate one phase , then connect it to another two wires to activate 2nd phase then connect to another two wires to activate the 3rd phase. This would have to be done alot faster than you could switch wires around since one phase would not turn the motor shaft a complete rotation, it takes all 3 phases to spin the shaft. This is essentially what the esc does without all the manual switching of the wires (its more technical than this but that pretty much the basic of it)

Keeping a battery connected to just one phase for an extended time(its basically just a long loop of wire) will short your battery/motor since the energy from that battery has no where to go creating lots of heat.

This is what a short or also known as a dead short, does to a lipo
[youtube]http://www.youtube.com/watch?v=o5bYITU6KA0&feature=related[/youtube]

And this is what would happen with your nicads
[youtube]http://www.youtube.com/watch?v=Ix9hQNCmV0E[/youtube]

As suggested from above you if your looking for just connecting your battery to the motor with a switch you'll have to use a brushed motor.

RE: Ni-Cads & Brushless motors ????
 

ok, i think we all know he knows not to direct power a brushless motor.

depending on what you need it to do, and the size of the motor required brushed motors can get up and going pretty fast, small motors can easily hit 40K rpm, and low turn 540 sized v-brushed (think 8 turn) can really crank out the RPM's. IF you dont need high torque and IF you dont need long running times, i would go brushed.