Underhung motors - Do shorting rings matter?

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Robh3606

Robh3606

Member
Joined 2002
Can't say for sure but JBL used a SRG magnet structure on the E-145 which uses an underhung coil. The SFG motors have shorting rings. They also used a shorting ring SFG in the 9800 woofer the 1500 AL. This woofer is also underhung.

Rob :)
 
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T

Tenson

Member
Joined 2006
audiosmile.co.uk
Thanks, I did find that 'narod.ru' article too.

So far all the implementations I have seen use shorting rings above and below the air gap. I think they are purely to short the eddy currents generated by the VC that is outside the air gap. I always thought that would be only for overhung designs, but I suppose even the VC of an underhung design can move outside the air-gap at higher excursions such as in LF drivers. So perhaps that is why we see them in underhung woofers.

I have not seen any IRL implementations of shorting rings / sleeves inside the air gap. For example any midrange drivers where the excursion is always minimal that use shorting rings?

EDIT: Zaphs site says the Adire Extremis 6.8 uses a shorting sleeve right through the motor. Ooh pictures here! https://aranmaracoustics.com.au/extremis.html

X_68_Motor_Assy_Xplod[1].jpg

X_68_Motor_Assy_Cut1[1].jpg
 
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hurrication

Member
Joined 2012
Inductance management via shorting rings is the same in both overhung and underhung motors. There are plenty of overhung motors that have shorting rings through the gap, not just above and below the gap. An overhung motor that has a full pole sleeve has a shorting ring in the gap.
It is very beneficial even in an underhung design. For some data on this, take a peek at my underhung neo radial subwoofer project that employs a full aluminum shorting ring throughout the entire motor: https://www.diymobileaudio.com/threads/aurasound-ns15-ns18.455165/page-4#post-6100900
 
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B

benb

Member
Joined 2010
hurrication said:
Inductance management via shorting rings is the same in both overhung and underhung motors. There are plenty of overhung motors that have shorting rings through the gap, not just above and below the gap. An overhung motor that has a full pole sleeve has a shorting ring in the gap.
It is very beneficial even in an underhung design. For some data on this, take a peek at my underhung neo radial subwoofer project that employs a full aluminum shorting ring throughout the entire motor: https://www.diymobileaudio.com/threads/aurasound-ns15-ns18.455165/page-4#post-6100900
Click to expand...
Great work, I've been wondering if there were any DIY driver peeps posting somewhere.
 
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