Can I run a "brushless DC FAN" backwards?
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From: John Ferrell on 3 Aug 2010 11:17 Brushless motors that I am familiar with have three wires connecting them to a controller board. swap any two of those wires and the motor reverses. It should be easy to do with a DPDT relay. Please let us know how it works out. My Email address is in the open... On Mon, 02 Aug 2010 00:35:51 -0700, mike <spamme0(a)go.com> wrote: >I have a project that needs reversible fans. >Can I make a brushless fan go backwards? >Is it as simple as swapping the leads on the coils? >Or is there more to it, like wrong phase for the magnetic pulse >into the hall device? > >And then there's the question whether the blades will >move as much air running backwards. > >The muffin fan is the ideal form factor for this job. > >Only other cost effective thing I can think to do is >put two fans in series and run either one. > >I really don't want to spend the money to buy reversible fans >even if they're available. I gots boxes of muffin fans. > >Ideas? >Thanks, mike John Ferrell W8CCW
From: Jim Thompson on 3 Aug 2010 11:21 On Tue, 03 Aug 2010 11:17:22 -0400, John Ferrell <jferrell13(a)triad.rr.com> wrote: >Brushless motors that I am familiar with have three wires connecting >them to a controller board. swap any two of those wires and the motor >reverses. It should be easy to do with a DPDT relay. >Please let us know how it works out. > >My Email address is in the open... > >On Mon, 02 Aug 2010 00:35:51 -0700, mike <spamme0(a)go.com> wrote: > >>I have a project that needs reversible fans. >>Can I make a brushless fan go backwards? >>Is it as simple as swapping the leads on the coils? >>Or is there more to it, like wrong phase for the magnetic pulse >>into the hall device? >> >>And then there's the question whether the blades will >>move as much air running backwards. >> >>The muffin fan is the ideal form factor for this job. >> >>Only other cost effective thing I can think to do is >>put two fans in series and run either one. >> >>I really don't want to spend the money to buy reversible fans >>even if they're available. I gots boxes of muffin fans. >> >>Ideas? >>Thanks, mike >John Ferrell W8CCW But "muffin" fans generally have the controller built-in. IF they have a third wire it's for speed sensing. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Spice is like a sports car... Performance only as good as the person behind the wheel.
From: mike on 3 Aug 2010 15:33 John Ferrell wrote: > Brushless motors that I am familiar with have three wires connecting > them to a controller board. swap any two of those wires and the motor > reverses. It should be easy to do with a DPDT relay. > Please let us know how it works out. > > My Email address is in the open... > > On Mon, 02 Aug 2010 00:35:51 -0700, mike <spamme0(a)go.com> wrote: > >> I have a project that needs reversible fans. >> Can I make a brushless fan go backwards? >> Is it as simple as swapping the leads on the coils? >> Or is there more to it, like wrong phase for the magnetic pulse >> into the hall device? >> >> And then there's the question whether the blades will >> move as much air running backwards. >> >> The muffin fan is the ideal form factor for this job. >> >> Only other cost effective thing I can think to do is >> put two fans in series and run either one. >> >> I really don't want to spend the money to buy reversible fans >> even if they're available. I gots boxes of muffin fans. >> >> Ideas? >> Thanks, mike > John Ferrell W8CCW Way cool that W8CCW knows how to run fans counter colckwise .... .. ;-) Looks like I'm stuck with two fans back to back.
From: Glenn Gundlach on 3 Aug 2010 23:47 On Aug 3, 8:17 am, John Ferrell <jferrel...(a)triad.rr.com> wrote: > Brushless motors that I am familiar with have three wires connecting > them to a controller board. swap any two of those wires and the motor > reverses. It should be easy to do with a DPDT relay. > Please let us know how it works out. > > My Email address is in the open... > <snip> > > John Ferrell W8CCW A reversible BRUSHLESS fan ? They smoke when reverse powered - and they won't even blow the smoke away. G²
From: John Ferrell on 4 Aug 2010 11:50
http://www.gobrushless.com/kb/index.php?title=FAQ http://www.castlecreations.com/ The intervention must be performed between the actual motor and controller. The above links are the shallow and deep ends of the brushless pool for Radio Control model airplanes. Note the prices on the Castle controllers! I suppose it could be that there are motors called brushless that are not three phase devices. Swap any two MOTOR wires! > >But "muffin" fans generally have the controller built-in. IF they >have a third wire it's for speed sensing. > > ...Jim Thompson John Ferrell W8CCW |