Hi all... I need to make a circuit that needs to spin on the shaft of a small dc brushless motor. I thought I could use a permanent magnet mounted on the base of the shaft of the motor (not moving) and some coils that will be spinning on the pcb. I don't know if this will work or provide enough power (need 5mA) to the spinning pcb . Any better ways ? BTW I can't seem to find a dc brushless motor manufacturer. Can you suggest any ? Thanks
How to provide power to a spinning circuit ?
Started by ●July 21, 2004
Reply by ●July 21, 20042004-07-21
Hi all... I need to make a circuit that needs to spin on the shaft of a small dc brushless motor. I thought I could use a permanent magnet mounted on the base of the shaft of the motor (not moving) and some coils that will be spinning on the pcb. I don't know if this will work or provide enough power (need 5mA) to the spinning pcb . Any better ways ? BTW I can't seem to find a dc brushless motor manufacturer. Can you suggest any ? Thanks
Reply by ●July 21, 20042004-07-21
On Wed, 21 Jul 2004 20:37:10 GMT, Rodo wrote:> Hi all... > > I need to make a circuit that needs to spin on the shaft of a small dc > brushless motor. I thought I could use a permanent magnet mounted on the > base of the shaft of the motor (not moving) and some coils that will be > spinning on the pcb. I don't know if this will work or provide enough power > (need 5mA) to the spinning pcb . Any better ways ? > > BTW I can't seem to find a dc brushless motor manufacturer. Can you suggest > any ? > > ThanksSlip rings? -- "Just machines that make big decisions programmed by fellas with compassion and vision." -D. Fagen (remove yomama)
Reply by ●July 21, 20042004-07-21
Rodo <dsp1024@yahoo.com> wrote:> Hi all...> I need to make a circuit that needs to spin on the shaft of a small dc > brushless motor. I thought I could use a permanent magnet mounted on the > base of the shaft of the motor (not moving) and some coils that will be > spinning on the pcb. I don't know if this will work or provide enough power > (need 5mA) to the spinning pcb . Any better ways ?One simple approach is to use a small motor with the body attached to your PCB and the shaft fixed. Attach a pulley to the body of the motor and spin it with another motor. Take power from the leads of the motor attached to your PCB. -- Burn the land and boil the sea, You can't take the sky from me.
Reply by ●July 21, 20042004-07-21
"Jim Stewart" <jstewart@jkmicro.com> wrote in message news:Ee2dncePPugmfGPdRVn-ig@omsoft.com...> Rodo wrote: > > Hi all... > > > > I need to make a circuit that needs to spin on the shaft of a small dc > > brushless motor. I thought I could use a permanent magnet mounted on the > > base of the shaft of the motor (not moving) and some coils that will be > > spinning on the pcb. I don't know if this will work or provide enoughpower> > (need 5mA) to the spinning pcb . Any better ways ? > > You left out too many details. > > 1. How fast?100 rpm or more> 2. How many are you going to build?more than one> 3. How much money do you have?enough> 4. How long does it have to last?5 yrs> > > BTW I can't seem to find a dc brushless motor manufacturer. Can yousuggest> > any ? > > Google is your friend.So is yahoo. Everything I hit seems to be large dc motors. Thanks
Reply by ●July 21, 20042004-07-21
Rodo wrote:> "Jim Stewart" <jstewart@jkmicro.com> wrote in message > news:Ee2dncePPugmfGPdRVn-ig@omsoft.com... > >>Rodo wrote: >> >>>Hi all... >>> >>>I need to make a circuit that needs to spin on the shaft of a small dc >>>brushless motor. I thought I could use a permanent magnet mounted on the >>>base of the shaft of the motor (not moving) and some coils that will be >>>spinning on the pcb. I don't know if this will work or provide enough > > power > >>>(need 5mA) to the spinning pcb . Any better ways ? >> >>You left out too many details. >> >>1. How fast? > > > 100 rpm or more > > >>2. How many are you going to build? > > > more than oneOk, let me ask the question since you seem somewhat reluctant. Are you going to have assemblers build these in large quantities will you build a few in your garage or somewhere in between. I seriously doubt anyone here is going to steal your design based on what you've told/not told us.> >>3. How much money do you have? > > > enoughOk, how much do you expect to spend per unit?> >>4. How long does it have to last? > > > 5 yrsRules out slip rings. I'd use an inductive coupling. Sony and others have used them to power the preamp and/or deliver erase current on the spinning helical head assembly for videotape> >>>BTW I can't seem to find a dc brushless motor manufacturer. Can you > > suggest > >>>any ? >> >>Google is your friend. > > > So is yahoo. Everything I hit seems to be large dc motors.Then add "fractional horsepower" to your search term.> Thanks > >
Reply by ●July 21, 20042004-07-21
> I need to make a circuit that needs to spin on the shaft of a small dc > brushless motor. I thought I could use a permanent magnet mounted on theAs a point of reference for you: Dremel makes a lamp for their tools, which takes off power using magnetic coupling: It consists of a permanent magnet (this goes on the shaft of the tool) and a coil assy that wraps around it, and the coil is connected to two LEDs. Probably around 60mA.
Reply by ●July 21, 20042004-07-21
>> 1. How fast? > >100 rpm or more > >> 2. How many are you going to build? > >more than one > >> 3. How much money do you have? > >enough > >> 4. How long does it have to last? > >5 yrsUse a rotating transformer.
Reply by ●July 22, 20042004-07-22
On Wed, 21 Jul 2004 20:37:10 GMT, the renowned "Rodo" <dsp1024@yahoo.com> wrote:>Hi all... > >I need to make a circuit that needs to spin on the shaft of a small dc >brushless motor. I thought I could use a permanent magnet mounted on the >base of the shaft of the motor (not moving) and some coils that will be >spinning on the pcb. I don't know if this will work or provide enough power >(need 5mA) to the spinning pcb . Any better ways ?One way might be to modify the motor so you can draw power from the rotor windings. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by ●July 22, 20042004-07-22
Rodo wrote:> "Jim Stewart" <jstewart@jkmicro.com> wrote in message > news:Ee2dncePPugmfGPdRVn-ig@omsoft.com... > >>Rodo wrote: >> >>>Hi all... >>> >>>I need to make a circuit that needs to spin on the shaft of a small dc >>>brushless motor. I thought I could use a permanent magnet mounted on the >>>base of the shaft of the motor (not moving) and some coils that will be >>>spinning on the pcb. I don't know if this will work or provide enough power >>>(need 5mA) to the spinning pcb . Any better ways ?A bright lamp, and a solar cell... ? :)>> >>You left out too many details. >> >>1. How fast? > > > 100 rpm or moreYou are going to need a generator of some sort. At such low speeds, the simple magnet/coil is going to struggle, so you probably need higher frequency resonant coupling ( see electric toothbrush chargers ) - these use ferrite coils, with a frequency chosen for maximum power transfer, somewhere in 15Khz-150Khz regions. -jg
