Heater output

Post by **RogerRust** » Fri Nov 20, 2009 12:22 pm

I've posted a reply in a thread about demisting.

LINK HERE.

I would be interested to see if it works - if some one has 10 minutes give it a try!

Post by **bmcecosse** » Fri Nov 20, 2009 6:03 pm

I always assumed these motors would run same direction - no matter the polarity. Most DC motors do - unless they have permanent magnets for the field!

Post by **RogerRust** » Fri Nov 20, 2009 6:14 pm

No, it definitely runs different ways with the polarity change. The MG one has a label that shows the rotation direction dependant on the connections.

I think it may be a major factor in the poor porformance of the blower.

linearaudio · Post by **linearaudio** » Fri Nov 20, 2009 7:33 pm

You may have hit on something there- so obvious that everyone has overlooked it!! I've half a mind to try it now, in the dark, I'm that excited about the prospect of a blower that works! Don't think my situation is helped either by all the leaks- it seems to puff more heat out round the control slider than anywhere else! Just another job on the list...

linearaudio · Post by **linearaudio** » Sun Nov 22, 2009 4:36 pm

Just spent a while with tissue paper and swapping wires around. Sorry to say there is no noticeable difference in puff which ever way round you connect the wires. Also the note of the fan is same, not sounding faster/ noisier either way. A big disappointment to me, as I really wanted it to make a difference!

Post by **billlobban** » Sun Nov 22, 2009 4:46 pm

AC motors run the same way whichever way you connect them (not 3 phase) But many DC motors are polarity concious

Post by **bmcecosse** » Sun Nov 22, 2009 4:51 pm

Only if they have permanent magnets for field excitation! ie Model trains/Scalextric cars that sort of thing. I will be v surprised if the heater motor has magnets inside! DC motors with electro magnetic field will always run same direction, no matter the polarity - the field being reversed at the same time as the rotor current is reversed, thus motor runs same way. Flemings Left Hand Rule!
Single phase AC motors will run either direction - but are not self starting! So - a starting coil is fitted, which ensures they will run in the intended direction.

Post by **Bazzalucas** » Sun Nov 22, 2009 9:58 pm

Tried the wire swap and tissue paper experiment in my '58...absolutely no discernible difference. Sigh.